MS4 Permit Improvement Guide 

MS4 PERMIT IMPROVEMENT GUIDE

U.S. ENVIRONMENTAL PROTECTION AGENCY

MS4 Permit 

Improvement Guide

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF WATER

OFFICE OF WASTEWATER MANAGEMENT

WATER PERMITS DIVISION

APRIL 2010 

EPA 833-R-10-001 
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UNITED STATES ENVIRONMENTAL PROTECTlON AGENCY 

WASHINGTON 0 C 20480

APR 14 al10 

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W"'I(~ Dear NPDES Stormwater Managers, 

I am pleased to announce thai the Environmental Protection Agency (EPA) has completed the "Municipal 

Separate Storm Sewer System Permit Improvement Guide.- The primary purpose oflhis guidance 

document is to assist National Pollutant Discharge Elimination System (NPDES) pennit writm in 

smngthening municipal separate storm se.....er S)Slem (MS4) permits. 

This Guide contains examples of permit conditions and supporting rationale that cou ld be used in fact 

sheets that accompany NPDES permits. The Guide also inc ludes ~ommendations for pennit writers on 

how to tailor the language depending on the type of permiL For example, permilS covering traditional 

municipalities may contain different permit ptOvi.sion.s than those covering non-tradittonal entities like 

departments oftransponation. universities, and prisons. 

I ask that permit writers review the permit language and corresponding diiCussion presented in this Guide 

and consider how to incorporate this, or similar, language into their MS4 permits. Some modification of 

the language may be necessary to make it suitable for use with specinc MS4 permits. and to better tailor it 

to mectthe needs and goals of the various penninin& authorities. 

The pennit language suggested in this Guide is not intended to override already existing. more stringent 

or differently-worded provisions that are equally as protect ~e in meeting the applicable regulations. EPA 

expects the permitting authority to continue to make sig,nific:ant progreH and ensure that the intent of the 

regu lations or more stringent requirements is captured in the permit. 

In addition, EPA v.ould like to particularly stress the following key principles: 

• 	 Pennit provisions should be clear, specifIC. measurable. and enforceable Pennit:s shou ld inc lude 

specific deadlines for compliance, incorporate clear perfonnance stand3rds, and include 

measurable goals or quantifiable targets for implementation. 

• 	 Permits should contain a performance standard for pos ~nstruction that is based on the objective 

of maintaining or rC"storin& stable hydrology to protect water quality o f receiving waters Of 

another mechanism as effective. 

EPA has begun a rulemaking to strengthen the stormwater program. Using this Guide 10 improve permits 

represents the direction that EPA is taking 10 strengthen the program. This Guide is a li.....ing document 

that will be updated as new information for improving the stonnwater program is obtained. 

I appreciate your continued efforts in strengthening the NPDES municipal storm"'atcr program. (fyou 

have any questions about this Guide or suggestions for further improvements. please contact Rachel 

Herbert of my staff at herbt:r1.rxhcl1i'g-...cov or call her at 202·564·2649. 

Sincerely. 

i:::fl.~ Water Permits Division 

CC: 	 State Stonnwater CoonIinators 

Association of State and Interstate Water Pollution Control Administraton; 

flwntl ~s,UR, • t'ltIJ! 1IIfkW. goo.. 

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MS4 Permit Improvement Guide 

Contents 

Introduction & Getting Started............................................................................................................................1

Purpose......................................................................................................................................................................1

Contents of this Guide ...............................................................................................................................................1

How to Use this Guide ...............................................................................................................................................2

Preparing to Write an MS4 Permit ............................................................................................................................3

MS4 Permit Writing Tips............................................................................................................................................5

The Use of Partnerships in MS4 Permits ...................................................................................................................6

Chapter 1: Establishment of the Stormwater Management Program ...................................................................8

Introduction...............................................................................................................................................................8

1.1 Requirement to Develop a Stormwater Management Program ......................................................................9

1.2 Requirement to Develop Adequate Legal Authority to Implement and Enforce Stormwater 

Management Program ...................................................................................................................................10

1.3 Enforcement Measures and Tracking.............................................................................................................13

1.4 Requirement to Ensure Adequate Resources to Comply with MS4 Permit ...................................................16

Chapter 2: Public Education and Outreach/Public Involvement..........................................................................18

Introduction.............................................................................................................................................................18

2.1 Developing a Comprehensive Stormwater Education/Outreach Program ....................................................18

2.2 Involving the Public in Planning and Implementing the SWMP .....................................................................22

Chapter 3: Illicit Discharge Detection and Elimination........................................................................................24

Introduction.............................................................................................................................................................24

3.1 IDDE Program Development...........................................................................................................................24

3.2 MS4 Mapping .................................................................................................................................................26

3.3 Identification of Priority Areas .......................................................................................................................27

3.4 Field Screening................................................................................................................................................29

3.5 IDDE Source Investigation and Elimination ....................................................................................................32

3.6 Public Reporting of Non-Stormwater Discharges and Spills...........................................................................34

3.7 Illicit Discharge Education & Training .............................................................................................................36

Chapter 4: Construction ....................................................................................................................................37

Introduction.............................................................................................................................................................37

4.1 Construction Requirements and Control Measures .......................................................................................38

4.2 Construction Site Inventory............................................................................................................................40

4.3 Construction Plan Review Procedures............................................................................................................41

4.4 Construction Site Inspections and Enforcement ............................................................................................43

4.5 MS4 Staff Training ..........................................................................................................................................46

4.6 Construction Site Operator Education & Public Involvement ........................................................................47

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures .....................................49

Introduction.............................................................................................................................................................49

5.1 Post-Construction Stormwater Management Program .................................................................................50

5.2 Site Performance Standards ...........................................................................................................................51

5.3 Site Plan Review .............................................................................................................................................57

5.4 Long-Term Maintenance of Post-Construction Stormwater Control Measures.............................................58

5.5 Watershed Protection ....................................................................................................................................59

5.6 Tracking of Post-Construction Stormwater Control Measures.......................................................................62

5.7 Inspections and Enforcement.........................................................................................................................63

5.8 Retrofit Plan....................................................................................................................................................64

ii
MS4 Permit Improvement Guide 

iii

Chapter 6: Pollution Prevention/Good Housekeeping........................................................................................67

Introduction.............................................................................................................................................................67

6.1 Municipal Facility and Control Inventory .......................................................................................................68

6.2 Facility Assessment.........................................................................................................................................70

6.3 Development of Facility-Specific Stormwater Management SOPs and Implementation of Facility 

Stormwater Controls......................................................................................................................................71

6.4 Storm Sewer System Maintenance Activities.................................................................................................74

6.5 Flood Management ........................................................................................................................................81

6.6 Pesticide, Herbicide, and Fertilizer Application and Management ................................................................82

6.7 Training and Education...................................................................................................................................83

6.8 Contractor Requirements and Oversight........................................................................................................84

Chapter 7: Industrial Stormwater Sources .........................................................................................................85

Introduction.............................................................................................................................................................85

7.1 Facility Inventory ............................................................................................................................................85

7.2 Industrial Facility Stormwater Control Measures...........................................................................................88

7.3 Industrial and Commercial Facility Inspections ..............................................................................................91

7.4 Staff Training ..................................................................................................................................................94

Chapter 8: Monitoring, Evaluation, and Reporting .............................................................................................95

Introduction.............................................................................................................................................................95

8.1 Consolidated Information Tracking System....................................................................................................95

8.2 Development of a Comprehensive Monitoring & Assessment Program........................................................97

8.3 Evaluation of Overall Program Effectiveness................................................................................................102

8.4 Requirements for Annual Reporting of MS4 Activities.................................................................................104

Appendix A: Summary Annual Report Template ..............................................................................................107

Appendix B: Definitions...................................................................................................................................108
MS4 Permit Improvement Guide 

INTRODUCTION & GETTING STARTED

Purpose 

The primary purpose of the MS4 Permit Improvement Guide (Guide) is to assist National Pollutant 

Discharge Elimination System (NPDES) permit writers in strengthening municipal separate storm sewer 

system (MS4) stormwater permits. The objective of the Guide is to facilitate the creation of MS4 permits 

which are clear, consistent with applicable regulations, and enforceable. This Guide contains examples 

of permit conditions and supporting rationale that could be used in fact sheets that accompany NPDES 

permits. Permit language should include controls that identify specific actions permittees must perform 

to comply with the Permit Requirements. 

This Guide focuses in large part on permits for small (Phase II) MS4s. However, while the contents of the 

Guide are generally organized consistent with the six minimum control measures (40 CFR 123.34(b)) 

applicable to Phase II MS4 permits, however, permit writers may find this Guide useful for Phase I MS4 

permits. In addition, the Guide specifically addresses Phase I MS4 Permit Requirements with regard to 

the industrial program elements set forth in the Phase I regulations at 40 CFR 122.26(d)(2)(ii) and (iv)(C). 

These are addressed in Chapter 7. The Guide may also be useful for “non-traditional” MS4 permittees, 

such as departments of transportation (DOTs), universities and prisons. 

EPA has developed a Stormwater Phase II Final Rule Fact Sheet Series 

(www.epa.gov/npdes/stormwater/swfinal) to assist permitting authorities and permittees in 

understanding the Phase II regulations. Further, EPA has developed the National Menu of Stormwater 

Best Management Practices (www.epa.gov/npdes/stormwater/menuofbmps) which provides 

descriptive information in fact sheets about various best management practices associated with the 

Phase II six minimum control measures. 

The Guide was created by reviewing numerous MS4 permits and fact sheets from around the country. 

Some of the example permit and fact sheet language presented in this Guide has been adapted from 

these permits; in those instances where existing language that meets the purpose of this document was 

not available, EPA has crafted new language. 

Contents of this Guide 

This document is divided into parts, as noted above, based largely on the six minimum control measures 

required in the Phase II stormwater regulations (see 40 CFR 122.34(b)). Chapters 1 -6 address 

development and implementation of a stormwater management program (SWMP) and the six minimum 

control measures that must be included in the SWMP. Chapter 7 addresses industrial facilities programs 

relevant for Phase I MS4 permits. Chapter 8, Overall Evaluation and Adaptive Management, discusses 

reporting, evaluation, and tracking requirements. This Guide does not focus on the water quality 

provisions of the Clean Water Act, which may require more stringent requirements than those 

programmatic elements specified here. 

Introduction & Getting Started 1
MS4 Permit Improvement Guide 

Each chapter opens with an introduction providing a brief overview of relevant regulatory requirements 

pertaining to the subject of the chapter. Each chapter is then divided into sections in which the 

following topics are addressed: 

 Example Permit Provision – This section includes example MS4 permit language. The 

language has been formatted and numbered in such a way that each section corresponds 

directly to a permit structured in accordance with the chapter sequence of this Guide. EPA 

developed these examples by first surveying existing EPA and State MS4 permit language 

and drawing upon agency experience in implementing permits. EPA has identified the 

source of the language (in footnotes) if adapted from specific permits. 

 Example Permit Requirement Rationale for the Fact Sheet – This section describes the 

rationale for the example permit provision. This language can assist the permit writer in 

developing the fact sheet, which accompanies all NPDES permits; however, it is up to the 

permit writer to ensure that a complete and customized version of the fact sheet 

accompanies the permit. Example Permit Requirement Rationale for the Fact Sheet sections 

often describe “requirements” or steps that “must” be taken. To the extent this language is 

used in these sections, it is intended to describe requirements included in the example 

permit provisions. It does not mean that all permits ”must” include the specific 

“requirement” described. 

 Recommendations for the Permit Writer (included where appropriate) – This section 

discusses issues the permit writer should consider in determining how to use the example 

permit provisions. 

How to Use this Guide 

This guidance includes “example” MS4 permit language for specific program elements, but is not 

intended to be definitive or comprehensive for all MS4 Permit Requirements.1

 EPA recommends that 

permit writers review the example permit language presented in this guide and consider how to 

incorporate this, or similar, language into MS4 permits as appropriate. Each state may have different 

NPDES requirements along with varied experience overseeing MS4 programs, and MS4 permittees vary 

widely in storm water management experience and sophistication, size, topography, precipitation 

patterns, land use, receiving water conditions and other factors. In most instances, EPA anticipates that 

permit writers will modify the language to make it suitable for specific MS4 permits, and to tailor 

example provisions to meet the various needs and goals that apply. 

When possible, this Guide has tried to provide examples that can be used for both Phase I and Phase II 

permits. However, in some instances EPA has provided suggestions for how the language can be tailored 

to better fit within the context of a Phase I or Phase II permit. In addition, EPA acknowledges that some 

language presented in this Guide may be more suitable for an individual permit rather than a general 

permit. While EPA has presented a discussion for ways the language could be altered to fit these 

scenarios in Recommendations for the Permit Writer sections, it is up to the permit writer to determine 

the best use of the material for the permit being crafted. 

 

1

 For example, the guide does not explicitly address provisions for compliance with CWA section 402(p)(3)(B)(ii), 

water quality standards, applicable wasteload allocations in TMDLs or such other conditions as the permitting 

authority deems necessary. For information on integrating TMDLs into stormwater permits see USEPA’s DRAFT 

TMDLs to Stormwater Handbook (www.epa.gov/owow/tmdl/stormwater) 

Introduction & Getting Started 2
MS4 Permit Improvement Guide 

The example permit language in this Guide has been written as if the permit is a reissued permit and not 

an initial permit, since most MS4 permittees have been subject to NPDES permits for at least one permit 

term. Requirements to develop the initial SWMP are not included in this Guide since they would have 

been included in the first permit term. It is important that permit writers consider the different stages in 

the development and implementation of SWMPs when establishing permit conditions as well as the 

experience learned from other more advance programs. So, for example, this Guide includes brackets 

to indicate the place for an appropriate schedule or deadline rather than indicating specific timeframes 

in all instances. These examples are available to the permit writer, along with other resources such as 

the permittee’s draft or existing SMWP document, annual reports, prior permit experience, receiving 

water quality information and the permit writer’s best professional judgment, to issue permits suitable 

for their specific MS4s. 

The permit language suggested in this Guide is not intended to override already existing, more stringent 

or differently-worded provisions that are equally as compliant in meeting the applicable regulations and 

protective of water quality standards. EPA expects the permitting authority to ensure that the intent of 

all applicable regulations is captured in the permit. States with more stringent permit provisions should 

continue to strengthen these provisions as the permits are reissued. This Guide includes suggestions on 

how to develop permit language for MS4 permittees. This Guide does not impose any new legally 

binding requirements on EPA, States, or the regulated community, and does not confer legal rights or 

impose legal obligations upon any member of the public. In the event of a conflict between the 

discussion in this Guide and any statute, regulation, or permit the statute, regulation or permit controls. 

Terminology: SWMP and SWMP Document

This guide uses the term SWMP to refer to the stormwater management program that is required by the 

Phase I and Phase II regulations to be developed by MS4 permittees. The SWMP document is the written plan 

that is used to describe the various control measures and activities the permittee will undertake to implement 

the stormwater management program. 

Preparing to Write an MS4 Permit 

Most Phase II MS4 permittees are regulated under a general permit (with some exceptions where 

individual permits have been used for Phase II and non-traditional MS4 permittees). Phase I MS4 

permittees are regulated under individual permits, and can include multiple co-permittees. EPA 

regulations require that initial MS4 permits (i.e. first permit term) set the foundation of the permittee’s 

SWMP. For Phase II MS4 the focus is on the six minimum control measures in 40 C.F.R. 122.34(b), while 

the Phase I MS4 permittees are informed by the regulations at 40 C.F.R. 122.26(d). See Chapter 1 of this 

Guide. 

As the permit writer prepares to reissue an MS4 permit, regardless of whether the permit is an 

individual or general permit, EPA recommends that the permit writer review, at a minimum, the 

following sources of information: 

Past annual reports

For currently regulated MS4s, annual reports submitted by the permittee can include information 

that will help permit writers develop more specific and measurable Permit Requirements. The most 

recent annual report is usually the most helpful to review, but additional annual reports can be 

reviewed if time allows. If the permit writer is developing a general permit, a broad selection of 

Introduction & Getting Started 3
MS4 Permit Improvement Guide 

annual reports from various permittees should be reviewed. In particular, EPA recommends that 

the permit writer review, at a minimum, the following specific information: 

Areas of obvious strengths or weaknesses in the SWMP 

 For example, is the permittee vague about specific activities (often an indicator of a weak 

program area), or is the permittee clearly meeting the requirements of the permit and/or 

going above and beyond the minimum requirements? 

Trends or common compliance problems 

 For example, does the permittee analyze the data to assess the most common compliance 

problems, and then modify their controls/programs to address these problems? For 

example, do they use the common compliance issues identified to target their training and 

outreach/education efforts for construction operators? 

Level of implementation of SWMP activities (e.g., frequency and numbers of inspections, 

frequency of catch basin cleaning, street sweeping) 

 Does the permittee report the total universe when reporting the quantity of an activity 

achieved? For example, if the MS4 is required to conduct industrial inspections, does it 

report it did 100 inspections (which may be good or bad, depending on how many it was 

required to inspect), or that it did 100 out of 5,000 (only 2% of the total)? 

Water quality priorities for the permittee (e.g. impaired waters, TMDLs, high quality waters) 

 Does the permittee’s annual report describe priority pollutants for impaired waters and 

other water quality programs and what was done to reduce and/or eliminate their contact 

with stormwater? Does the SWMP target both impaired and high quality waters? 

Specific sources or pollutants of concern permittee is currently focusing on 

 Does the SWMP target pollutants of concern in its activities? 

Level and type of enforcement currently being used by permittee 

 Does the annual report provide data and summary information on the different types of 

enforcement actions taken (how many verbal warnings, written notes, fines, etc)? 

Any trends (i.e. water quality, compliance, control measure implementation levels) being 

reported by Permittees which indicate success or failure of particular SWMP components 

 Does the permittee analyze the data, or just report the data in the MS4 annual report? 

Types of measurable goals being applied and achieved by permittees 

 Has the permittee met the measurable goals stated in the permit and SWMP? 

Introduction & Getting Started 4
MS4 Permit Improvement Guide 

Stormwater management program (SWMP)

Review the most current SWMP documents for potential gaps that may need to be specifically 

addressed in the reissued MS4 permit. EPA’s MS4 Program Evaluation Guidance (available at 

www.epa.gov/npdes/pubs/ms4guide_withappendixa.pdf) can be used to assess the key elements in 

a SWMP. 

NPDES MS4 audit reports, construction/industrial/commercial site inspection reports

Review the findings from any MS4 audits conducted during the past permit term to help identify key 

issues that should be addressed in the next permit. For example, if the audits identified weak or 

missing program elements and other controls, these should be addressed in the reissuance of the 

permit. Construction, industrial, and/or commercial site inspection reports for facilities within the 

MS4’s boundary should be reviewed to determine if there are common compliance issues that 

should be addressed in the MS4 permit (for example, more training, more frequent inspections, 

more complete inventory or prioritization, etc.). 

Monitoring/Information on Quality of Receiving Waters

Review any monitoring data collected by the permittee or any other entity that has collected useful 

monitoring data to identify potential pollutants of concern. In addition, the most recent information 

on impaired waters and total maximum daily loads (TMDLs) for the permit area should be reviewed. 

If there are waste load allocations (WLAs) applicable to the permittee, these should be addressed in 

the permit. If no WLA has been assigned to the MS4, the permit writer should still consider 

pollutants of concern identified in 303(d) lists and TMDLs when developing Permit Requirements. 

Such information will help identify whether more targeted permit conditions are needed to reduce 

the discharge of these pollutants. This Guide does not specifically address the inclusion of TMDL 

requirements in MS4 permits. 

Permit renewal application data or past notice of intent (NOI) information

Review any permit renewal applications or NOIs submitted to establish coverage for the previous 

permit term. Permit writers should consider the recommendations made in the EPA “Interpretive 

Policy Memorandum on Reapplication Requirements for Municipal Separate Storm Sewer Systems” 

(www.epa.gov/npdes/pubs/owm0125.pdf) published in 1996 (40 CFR Part 122; Federal Register, 

Volume 61, Number 155). This document provides information which clarifies the MS4 

reapplication requirements and explains that MS4 permit applicants and NPDES permit writers have 

discretion to customize appropriate and streamlined reapplication requirements on a case-by-case 

basis. 

Previous MS4 permit

Finally, review any past MS4 permits to identify where permit language should be revised or 

completely rewritten, for example, because language was vague. This MS4 permit improvement 

Guide should be used help strengthen key areas in the permit. 

Note that if the MS4 permit is being issued for the first time, some of the above information will not 

exist yet, such as past annual reports or old SWMP documents. 

MS4 Permit Writing Tips 

There are a few general tips to keep in mind when writing MS4 permits. First, and most importantly, 

permit provisions should be clear, specific, measurable, and enforceable. Permits should include specific 

Introduction & Getting Started 5
MS4 Permit Improvement Guide 

deadlines for compliance, incorporate clear performance standards, and include measurable goals or 

quantifiable targets for implementation. Doing so will allow permitting authorities to more easily assess 

compliance, and take enforcement actions as necessary. 

For example, the following permit provision could be strengthened: “The permittee shall demonstrate 

compliance with this Permit through the timely implementation of control measures and other actions 

to reduce pollutants in discharges to the maximum extent practicable in accordance with their SWMP...” 

This permit provision does not define what “timely implementation” is, allowing the permittee to 

determine what is timely. Timely implementation could be, although it probably was not intended to be, 

interpreted as meaning up to five years, or it could mean that implementation must occur within six 

months. In addition, “other actions” are mentioned in this provision, but they are never described. If a 

permit requires “other actions,” these actions should be specifically described in the permit. Finally, it is 

important to strike a balance of providing specific Permit Requirements while still allowing the 

permittee come up with innovative controls. 

In addition, vague phrases such as “as feasible” and “as possible” should be avoided because they result 

in inconsistent implementation by permittees and difficulties in permit authority oversight and 

enforcement. The permit writer’s role is to determine what is necessary to achieve in a permit term, and 

to develop clear, enforceable language that conforms to these determinations. Accordingly, the permit 

should set forth objective standards, criteria or processes, which will aid the permittee in complying 

with the permit, as well as the permitting authority in determining compliance in the MS4 permit. 

In order for permit language to be clear, specific, measurable and enforceable, each Permit 

Requirement will ideally specify: 

 What needs to happen 

 Who needs to do it 

 How much they need to do 

 When they need to get it done 

 Where it is to be done 

For each Permit Requirement: “What” is usually the stormwater control measure or activity required. 

“Who” in most cases is implied as the permittee (although in some cases the permitting authority may 

need to specify who exactly will carry out the requirement if there are co-permittees). “How much” is 

the performance standard the permittee must meet (e.g., how many inspections). “When” is a specific 

time (or a set frequency) when the stormwater control measure or activity must be completed. 

“Where” indicates the specific location or area (if necessary). These questions will help determine 

compliance with the permit requirement. 

The Use of Partnerships in MS4 Permits 

Since the Phase II Rule applies to all small MS4s within an urbanized area regardless of political 

boundaries it is very likely that multiple governments and agencies within a single geographic area are 

subject to MS4 permitting requirements. For example, a city government that operates a small MS4 

within an urbanized area may obtain permit coverage under a general Phase II permit while other MS4s 

in the same vicinity (such as a county, other cities, or a state DOT) may have individual Phase I MS4 

permits. All permittees are responsible for permit compliance in their permitted area. Given the 

Introduction & Getting Started 6
MS4 Permit Improvement Guide 

Introduction & Getting Started 7

potential for overlapping activities in close proximity, EPA encourages permittees in a geographic area to 

establish cooperative agreements in implementing their stormwater programs. Partnerships and 

agreements between permittees and/or other agencies can minimize unnecessarily repeating activities 

and result in using available resources as efficiently as possible. Using existing tools and programs 

instead of creating new ones can allow permittees to focus resources on high priority program 

components instead. In addition by forming partnerships, water quality can be examined and improved 

on a larger, consolidated scale rather than on a piece-meal, site-by-site basis. 

In addition to requiring MS4 permittees to maintain records of program implementation such as 

inspection forms, monitoring data, dry weather screening reports, and notices of violation, EPA 

recommends that MS4 permits include requirements for permittees to summarize and analyze data and 

submit the analysis to the permitting authority. For example, as permittees are required to evaluate 

program compliance and appropriateness of best management practices, the permit could require 

permittees to address in annual reports questions such as: 

 For illicit discharge data, what are the most prevalent sources and pollutants in the illicit 

discharge data, and where are these illicit discharges occurring? How many illicit discharges 

have been identified, and how many of those have been resolved? How many outfalls or 

screening points were visually screened, how many had dry weather discharges or flows, at 

how many were field analyses completed and for what parameters, and at how many were 

samples collected and analyzed? Does the permittee need to conduct more inspections in 

these areas, or develop more specific outreach targeting these sources and pollutants? 

 For the construction data, what are the most common construction violations, and are there 

any trends in the data (e.g., construction operators who receive more violations than others, 

areas of the MS4 with more violations, need to refine guidance or standards to more clearly 

address common violations) How has the permittee responded to these trends? Over the 

last year, how many construction site SWPPP reviews were completed and approved? How 

many inspections were conducted, how many noncompliant sites were identified, and how 

many enforcement actions (and of what type) were taken? 

Also, although the stormwater Phase II rule requires reports, after the first permit term, reports are 

required to be submitted only in years two and four of the permit term. EPA strongly encourages annual 

reports for all permittees. (See 40 CFR 122.34(g)(3))
MS4 Permit Improvement Guide 

CHAPTER 1: ESTABLISHMENT OF THE STORMWATER MANAGEMENT 

PROGRAM

Introduction 

An over-arching legal authority framework must be established in 

order for the SWMP to be effective. Ensuring that the permittee has 

established the legal authority to meet the requirements of the 

permit, created a well described enforcement response plan (ERP), 

and allocated adequate resources will set a necessary foundation 

for the SWMP. 

Legal Authority 

Permittees must have the authority to carry out all aspects of their 

stormwater management programs, including requiring the control 

of pollutants flowing into the MS4 system, having access to inspect sources of pollutant discharges, and 

being able to compel compliance and issue citations in the event of violations. Legal authority is 

especially critical for construction site runoff control, post-construction/permanent runoff control, 

industrial and commercial inspections, and illicit discharge detection and elimination programs. (See 40 

CFR 122.26(d)(2)(i) and 40 CFR 122.34(b)(3)(ii)(B), (b)(4)(ii)(A), and (b)(5)(ii)(B)) 

Included Concepts

► Requirement to develop a 

stormwater management 

program 

► Necessary legal authority 

► Enforcement Measures 

and Tracking 

► Adequate resources 

A permittee seeking permit coverage under individual permits is required to describe the legal authority 

it has to implement and enforce the SWMP. EPA recommends that general permits also require 

regulated MS4s to describe their applicable legal authority in their Notices of Intent (NOIs) (40 CFR 

122.26(d)(2)(i), 122.33(b)). This legal authority is typically established through the adoption of one or 

more ordinances, or by modifying existing ordinances to provide the necessary authority. In some 

cases, a permittee might already have codified water quality provisions to address previous MS4 Permit 

Requirements; in this case, the permittee should be required to review existing codes and ordinances 

and prepare a statement detailing any necessary changes required to address the new MS4 permit 

requirements. Some permittees, such as, DOTs, universities, and prisons, may not have the authority to 

create and enforce ordinances. For these entities other mechanisms and authorities that they do 

possess should be utilized (e.g. DOT right-of-way permits). 

Enforcement Measures and Tracking 

Permittees are required by the Phase I and Phase II regulations to include in their ordinance, or other 

regulatory mechanism, penalty provisions to ensure compliance with construction and industrial 

requirements, to require the removal of illicit discharges, and to address noncompliance with postconstruction requirements. In complying with these requirements, EPA recommends the use of 

enforcement responses that vary with the type of permit violation, and escalate if violations are 

repeated or not corrected. EPA recommends that the permittee be required to develop and implement 

an enforcement response plan (ERP), which clearly describes the action to be taken for common 

violations associated with the construction program, industrial and commercial program, or other 

SWMP programs. A well-written ERP provides guidance to inspectors on the different enforcement 

Chapter 1: Establishment of the Stormwater Management Program 8
MS4 Permit Improvement Guide 

responses available, actions to address general permit non-filers, when and how to refer violators to the 

State, and how to track enforcement actions. 

Adequate Resources 

Each permittee will fund its SWMP differently; therefore, in order to assess whether adequate resources 

have been allocated to carry out the requirements of the MS4 permit, the permitting authorities should 

require their permittees to submit an accounting of stormwater-related budgets, costs, and staffing 

resources updated annually. The fiscal analysis should document and explain changes to budgets from 

year to year and describe how each type of funding can and cannot be used for stormwater program 

activities. (See 40 CFR 122.26(d)(2)(vi)). 

1.1 Requirement to Develop a Stormwater Management Program 

Example Permit Provision 

1.1.1 Requirement to Develop Program – The permittee must revise and update its 

written stormwater management program (SWMP) document and submit the 

SWMP to the [insert name of Permitting Authority] for review by [insert deadline, 

e.g., within one year of permit issuance]. The permittee must continue to implement 

the current SWMP until the revised SWMP is submitted. The SWMP does not 

contain effluent limitations; the limitations are contained in Parts [insert relevant 

part of the permit] of the permit. 

1.1.2 Contents of the SWMP document – At a minimum, the permittee must include the 

following information in its SWMP document: 

a. Ordinances, or other regulatory mechanisms, providing the legal authority 

necessary to implement and enforce the requirements of this permit (see Part 

1.1); 

b. Statement by the permittee’s legal counsel certifying to adequacy of legal 

authority (see Part 1.2); 

c. Written procedures describing how the permittee will implement provisions 

described in Parts 2-8. 

1.1.3 Modifications to the SWMP document – The [insert applicable name of permitting 

authority]may notify the permittee of the need to modify the SWMP document to 

be consistent with the permit, in which case the permittee will have [insert deadline, 

e.g. 90 days] to finalize such changes to the program. The permittee is required to 

keep the SWMP document up to date during the term of the permit. Where the 

permittee determines that modifications are needed to address any procedural, 

protocol, or programmatic change, such changes must be made as soon as 

practicable, but not later than [insert deadline, e.g. 90 days]. 

Chapter 1: Establishment of the Stormwater Management Program 9
MS4 Permit Improvement Guide 

Example Permit Requirement Rationale for the Fact Sheet 

The permittee is required to develop a SWMP document that describes how the permittee will 

meet the control requirements in the permit. (See 40 CFR 122.26(d)(2)(iv), 122.34(a)). The 

SWMP document is a consolidation of all of the permittee’s relevant ordinances or other 

regulatory requirements, the description of all programs and procedures (including standard 

forms to be used for reports and inspections) that will be implemented and enforced to comply 

with this permit and to document the selection, design, and installation of all stormwater 

control measures. The permittee is required to submit its SWMP document to the permitting 

authority. If modifications to the SWMP are necessary then the permitting authority will notify 

the permittee. 

Recommendation for the Permit Writer 

The permit writer should include in this section the relevant parts of the permit that require specific 

descriptions or justifications to be included in the SWMP document. Also, permit writers may need 

to include an additional requirement regarding the submittal of the SWMP document since some 

information contained in the SWMP document is required to be submitted prior to the permittee 

obtaining permit coverage. In addition, permit writers should refer to the memo entitled Interim 

Guidance on Implementation of NPDES Regulations for Storm Water Phase II for Small Municipal 

Separate Storm Sewer Systems in Response to Recent Ninth Circuit Decision in Environmental 

Defense Center, et al. v. EPA, No. 00-70014 & consolidated cases (9thCir.) for additional guidance on 

the implementation of regulations for Phase II MS4s 

(www.epa.gov/npdes/pubs/interim_guidelines_memo_final.pdf). 

1.2 Requirement to Develop Adequate Legal Authority to Implement 

and Enforce Stormwater Management Program 

Example Permit Provision 

1.2.1 Within [insert deadline, e.g., one year from permit issuance] the permittee must 

review and revise its relevant ordinances or other regulatory mechanisms, or adopt 

any new ordinances or other regulatory mechanisms that provide it with adequate 

legal authority to control pollutant discharges into and from its MS4, and to meet 

the requirements of this permit. 

1.2.2 To be considered adequate, this legal authority must, at a minimum, address the 

following: 

a. Authority to Prohibit Illicit Discharges – Prohibit and eliminate illicit connections 

and discharges to the MS4. Illicit connections include pipes, drains, open 

channels, or other conveyances that have the potential to allow an illicit 

discharge to enter the MS4. Illicit discharges include all non-stormwater 

discharges except fire fighting discharges, discharges from NPDES permitted 

industrial sources and discharges not otherwise authorized under Part 1.2.2.b. of 

this permit. 

Chapter 1: Establishment of the Stormwater Management Program 10
MS4 Permit Improvement Guide 

b. Allowable Non-Stormwater Discharges –Exceptions to the prohibition in Part 

1.2.2.a. may include the following, only if they are considered non-significant 

contributors of pollutants: water line flushing, landscape irrigation, diverted 

stream flows, rising ground waters, uncontaminated ground water infiltration 

(as defined at 40 CFR 35.2005(20)) to separate storm sewers, uncontaminated 

pumped ground water, discharges from potable water sources, foundation 

drains, air conditioning condensation, irrigation water, springs, water from crawl 

space pumps, footing drains, lawn watering, individual residential car washing, 

flows from riparian habitats and wetlands, dechlorinated swimming pool 

discharges, and street wash water. 

c. Authority to Prohibit Spills or Other Releases – Control the discharge of spills, 

and prohibit dumping or disposal of materials other than stormwater into the 

MS4. 

d. Authority to Require Compliance – Require compliance with conditions in the 

permittee’s ordinances, permits, contracts, or orders (i.e., hold dischargers 

accountable for their contributions of pollutants and flows). 

e. Authority to Require Installation, Implementation, and Maintenance of Control 

Measures – Require owners/operators of construction sites, new or 

redeveloped land, and industrial and commercial facilities to minimize the 

discharge of pollutants to the MS4 through the installation, implementation, and 

maintenance of stormwater control measures consistent with [insert references 

to applicable stormwater control measure manuals, guidance documents, etc.]. 

f. Authority to Receive and Collect Information – The permittee must have the 

authority to request from operators of construction sites, new or redeveloped 

land, and industrial and commercial facilities information such as stormwater 

plans, inspection reports, and monitoring results, and other information deemed 

necessary to assess compliance with this permit. The permittee must also have 

the authority to review designs and proposals for new development and 

redevelopment to determine whether adequate stormwater control measures 

will be installed, implemented, and maintained. 

g. Authority to Inspect – The permittee must have the authority to enter private 

property for the purpose of inspecting at reasonable times any facilities, 

equipment, practices, or operations related to stormwater discharges to 

determine whether there is compliance with local stormwater control 

ordinances/standards or requirements in this Permit. 

h. Response to Violations – The permittee must have the ability to promptly 

require that violators cease and desist illicit discharges or discharges of 

stormwater in violation of any ordinance or standard and/or cleanup and abate 

such discharges, including the ability to: 

1. Effectively require the discharger to abate and clean up their discharge, spill, 

or pollutant release within [insert deadline, e.g. 48 hours] of notification; or 

2. For uncontrolled sources of pollutants that could pose an environmental 

threat, require abatement within [insert timeframe, e.g. 30 days of 

notification]; or, 

Chapter 1: Establishment of the Stormwater Management Program 11
MS4 Permit Improvement Guide 

3. Perform the clean up and abatement work and bill the responsible party, if 

necessary. 

4. If a situation persists where pollutant-causing sources or activities are not 

abated, provide the option to order the cessation of activities until such 

problems are adequately addressed. 

5. When all parties agree that clean-up activities cannot be completed within 

the timeframe provided, determine a new timeframe and notify the [insert 

name of permitting authority]. 

i. Monetary Penalties – The permittee must have the ability to: 

1. Levy citations or administrative fines against responsible parties either 

immediately at the site, or within a few days. 

2. Require recovery and remediation costs from responsible parties. 

j. Civil/Criminal Penalties – The permittee must have the ability to impose more 

substantial civil or criminal sanctions (including referral to a city or district 

attorney) and escalate corrective response, consistent with its enforcement 

response plan developed pursuant to Part 1.3, for persistent non-compliance, 

repeat or escalating violations, or incidents of major environmental harm. 

k. Interagency Agreements – Control of the contribution of pollutants from one 

portion of the shared MS4 to another portion of the MS4 through interagency 

agreements or other similar agreements with other owners of the MS4, such as 

[insert other applicable permittees]. 

1.2.3 The permittee must include as part of its written SWMP document a statement 

certified by its chief legal counsel that the permittee has taken the necessary steps 

to obtain and maintain full legal authority to implement and enforce each of the 

requirements contained in this permit. This statement must include: 

a. Identification of all departments within the permittee’s jurisdiction that conduct 

stormwater-related activities and their roles and responsibilities under this 

permit. Include an up-to-date organizational chart specifying these departments, 

key personnel, and contact information. 

b. Identification of the local administrative and legal procedures and ordinances 

available to mandate compliance with stormwater-related ordinances and 

therefore with the conditions of this permit. 

c. A description of how stormwater related-ordinances are implemented and 

appealed. 

d. A description of whether the municipality can issue administrative orders and 

injunctions, or whether it must go through the court system for enforcement 

actions. 

Example Permit Requirement Rationale for the Fact Sheet 

Adequate legal authority is required to implement and enforce most parts of the SWMP. (See 

40 CFR 122.26(d)(2)(i) and 40 CFR 122.34(b)(3)(ii)(B), (b)(4)(ii)(A), and (b)(5)(ii)(B)). Without 

Chapter 1: Establishment of the Stormwater Management Program 12
MS4 Permit Improvement Guide 

adequate legal authority the MS4 would be unable to perform many vital SWMP functions such 

as performing inspections and requiring installation of control measures. In addition, the 

permittee would not be able to penalize and/or attain remediation costs from violators. 

Recommendations for the Permit Writer 

A major difference between a traditional MS4 and a non-traditional MS4 (such as a DOT, military 

base, or university) is often the scope of legal authority available to the MS4. Non-traditional MS4 

permittees often cannot pass “ordinances” nor do they have enforcement authority like a typical 

municipality, so legal authority may consist of policies, standards, or specific contract language. 

Non-traditional MS4 permittees also do not generally have the authority to impose a monetary 

penalty. Although these differences exist, just like traditional MS4s, non-traditional MS4s must have 

the legal authority to develop, implement, and enforce the program. Moreover, the scope of legal 

authority that may be exercised by MS4 operators that are municipalities may vary from state to 

state. Therefore, permit writers should tailor the legal authority section depending on the types of 

permittees covered and the scope of authority that may be exercised by the permittee. For 

example, non-traditional MS4 permittees often have authority over what their contracts require. 

Therefore, the permit could require that contracts for construction and maintenance activities 

include specific stormwater requirements that ensure the permittee’s requirements are met. In 

addition, cooperative agreements could be maintained with those permittees that do possess the 

legal authorities to enforce stormwater measures within the permittee’s MS4 boundary. 

The discharge prohibitions listed in Part 1.2.2 are taken from the Phase II regulations and are the 

minimum requirements. Note that, unlike Phase II MS4s, Phase I MS4 permittees are required to 

address the sources of non-stormwater discharges in Part 1.2.2.b. when they are identified as 

sources of pollutants in stormwater discharges. (See 40 CFR 122.26(d)(2)(iv)(B)). The permit writer 

may choose to apply additional or more stringent prohibitions. For example, some states have 

chosen to prohibit discharges from street washing activities as they can be significant sources of 

pollutants such as oil and grease and heavy metals. 

1.3 Enforcement Measures and Tracking 

Example Permit Provision 

1.3.1 The permittee must continue to implement, and revise within [specify deadline for 

completion, e.g. 12 months of permit issuance] if necessary, an enforcement 

response plan (ERP), which sets out the permittee’s potential responses to violations 

and addresses repeat and continuing violations through progressively stricter 

responses as needed to achieve compliance. The ERP must describe how the 

permittee will use each of the following types of enforcement responses based on 

the type of violation: 

a. Verbal Warnings – Verbal warnings are primarily consultative in nature. At a 

minimum, verbal warnings must specify the nature of the violation and required 

corrective action. 

Chapter 1: Establishment of the Stormwater Management Program 13
MS4 Permit Improvement Guide 

b. Written Notices – Written notices of violation (NOVs) must stipulate the nature 

of the violation and the required corrective action, with deadlines for taking 

such action. 

c. Escalated Enforcement Measures – The Permittee must have the legal ability to 

employ any combination of the enforcement actions below (or their functional 

equivalent), and to escalate enforcement responses where necessary to address 

persistent non-compliance, repeat or escalating violations, or incidents of major 

environmental harm: 

1. Citations (with Fines) – The ERP must indicate when the permittee will 

assess monetary fines, which may include civil and administrative penalties. 

2. Stop Work Orders – The permittee must have the authority to issue stop 

work orders that require construction activities to be halted, except for 

those activities directed at cleaning up, abating discharge, and installing 

appropriate control measures. 

3. Withholding of Plan Approvals or Other Authorizations – Where a facility is 

in non-compliance, the ERP must address how the permittee’s own approval 

process affecting the facility’s ability to discharge to the MS4 can be used to 

abate the violation. 

4. Additional Measures – The permittee may also use other escalated 

measures provided under local legal authorities. The permittee may perform 

work necessary to improve erosion control measures and collect the funds 

from the responsible party in an appropriate manner, such as collecting 

against the project’s bond or directly billing the responsible party to pay for 

work and materials. 

1.3.2 Enforcement Tracking – The Permittee must track instances of non-compliance 

either in hard-copy files or electronically. The enforcement case documentation 

must include, at a minimum, the following: 

a. Name of owner/operator of facility or site of violation 

b. Location of stormwater source (i.e., construction project, industrial facility) 

c. Description of violation 

d. Required schedule for returning to compliance 

e. Description of enforcement response used, including escalated responses if 

repeat violations occur or violations are not resolved in a timely manner 

f. Accompanying documentation of enforcement response (e.g., notices of 

noncompliance, notices of violations) 

g. Any referrals to different departments or agencies 

h. Date violation was resolved. 

1.3.3 Recidivism Reduction – The permittee is required to identify chronic violators of any 

SWMP component and reduce the rate of noncompliance recidivism. The permittee 

Chapter 1: Establishment of the Stormwater Management Program 14
MS4 Permit Improvement Guide 

must summarize inspection results by these chronic violators and include incentives, 

disincentives, or an increased inspection frequency at the operator’s sites. 2

Example Permit Requirement Rationale for the Fact Sheet 

The permit requires permittees to have an established, escalating enforcement policy that 

clearly describes the action to be taken for common violations. The policy must describe the 

procedures to ensure compliance with local ordinances and standards, including the sanctions 

and enforcement mechanisms that will be used to ensure compliance. (See 40 CFR 

122.26(d)(2)(i)). It is critical that the MS4 have the authority to initiate a range of enforcement 

actions to address the variability and severity of noncompliance. Enforcement responses to 

individual violations must consider criteria such as magnitude and duration of the violation, 

effect of the violation on the receiving water, compliance history of the operator, and good faith 

of the operator in compliance efforts. Particularly for construction sites, enforcement actions 

must be timely in order to be effective. 

Recommendations for the Permit Writer 

Typical enforcement mechanisms include verbal warnings, written NOVs, administrative fines and 

orders, stop work orders, and civil or criminal penalties. Some non-traditional MS4 permittees, such 

as DOTs and universities, may not have the authority to use the mechanisms described above. 

Therefore the enforcement requirements in the permit should take the permittee’s enforcement 

limitations and abilities into consideration, allow for alternative mechanisms such as related 

contract obligations or right-of-way permits, and/or require entities that cannot enforce to 

coordinate with those entities that can. For example, if a DOT discovers an illicit discharge to the 

right-of-way, a mechanism should be in place for the DOT to communicate with the adjacent 

municipality to eliminate the discharge in a timely manner. 

Some permit writers include specific language as to when permittees can refer violations of NPDES 

permits to the permitting authority. Because of the often similar control measures required in MS4 

construction programs and NPDES CGP SWPPP requirements, permit writers want the permittee to 

make an honest effort at achieving compliance with their local requirements before referring a 

violator to the NPDES permitting authority. An example of permit language on NPDES referrals, 

which require the MS4 permittee to make a good faith effort at ensuring compliance by conducting 

at least two inspections and notices of violation, follows: 

 NPDES Permit Referrals–For those construction projects or industrial facilities subject to the 

[insert name of applicable NPDES general construction/industrial permit], the permittee 

must: 

 

2

 Adapted from 2009 San Francisco Bay Municipal Regional Stormwater Permit (Order No. R2-2009-0074; 

www.swrcb.ca.gov/sanfranciscobay/board_decisions/adopted_orders/2009/R2-2009-0074.pdf) and the Los 

Angeles MS4 Permit (Part 3; 

www.swrcb.ca.gov/rwqcb4/water_issues/programs/stormwater/municipal/ms4_permits/los_angeles/2001-

2007/LA_MS4_Permit2001-2007.pdf) 

Chapter 1: Establishment of the Stormwater Management Program 15
MS4 Permit Improvement Guide 

Chapter 1: Establishment of the Stormwater Management Program 16

 a. Refer non-filers (i.e., those facilities that cannot demonstrate that they obtained permit 

coverage) to the [insert name of permitting authority] within [insert number of days, 

e.g. 30 days] of making that determination. In making such referrals, the permittee 

must include, at a minimum, the following documentation: 

1. Construction project or industrial facility location. 

2. Name of owner or operator. 

3. Estimated construction project size or type of industrial activity (including SIC code if 

known). 

4. Records of communication with the owner or operator regarding filing requirements. 

 b. Refer violations to the [insert name of permitting authority] provided that the 

permittee has made a good faith effort of progressive enforcement to achieve 

compliance with its own ordinances. At a minimum, the permittee’s good faith effort 

must include documentation of two follow-up inspections and two warning letters or 

notices of violation. In making such referrals, the permittee must include, at a 

minimum, the following documentation: 

1. Construction project or industrial facility location 

2. Name of owner or operator 

3. Estimated construction project size or type of industrial activity (including SIC code if 

known) 

4. Records of communication with the owner or operator regarding the violation, including 

at least two follow-up inspections, two warning letters or notices of violation, and any 

response from the owner or operator 

It is important to note that a referral to the permitting authority does not relieve the MS4 from its 

enforcement obligations. The MS4 must continue to work with the permitting authority, using all 

available enforcement authority in order to gain compliance. 

1.4 Requirement to Ensure Adequate Resources to Comply with 

MS4 Permit 

Example Permit Provision 

1.4.1 Secure Resources – The permittee must secure the resources necessary to meet all 

requirements of this permit. 

1.4.2 Annual Fiscal Analysis – The permittee must conduct an annual analysis of the 

capital and operation and maintenance expenditures needed, allocated, and spent 

as well as the necessary staff resources needed and allocated to meet the 

requirements of this permit, including any development, implementation, and 
MS4 Permit Improvement Guide 

enforcement activities required. The analysis must include estimated expenditures 

for the reporting period, the preceding period, and the next reporting period and be 

submitted with the annual report. 

a. Each analysis must include a description of the source of funds that are 

proposed to meet the necessary expenditures, including legal restrictions on the 

use of such funds. 

b. Each analysis must include a narrative description of circumstances resulting in a 

[insert percentage, e.g. 25 percent or greater] annual change for any budget line 

items. 

c. Each analysis must include a description of the staff resources necessary to meet 

the requirements of this permit. 

Example Permit Requirement Rationale for the Fact Sheet 

The annual fiscal analysis will show the allocated resources, expenditures, and staff resources 

necessary to comply with the permit, and implement and enforce the permittee’s SWMP. (See 

40 CFR 122.26(d)(2)(vi). The annual analysis is necessary to show that the permittee has 

adequate resources to meet all Permit Requirements. The analysis can also show year-to-year 

changes in funding for the stormwater program. A summary of the annual analysis must be 

reported in the annual report (see Section 8.4 and Appendix A). This report will help the 

Permitting Authority understand the resources that are dedicated to compliance with this 

permit, and to implementation and enforcement of the SWMP, and track how this changes over 

time. 

Recommendations for the Permit Writer 

Permit writers should be specific when requesting financial analysis information from the permittee. 

The Annual Report Template provided in this Guide includes basic questions that should be 

adequate for Phase II MS4s. However, more detailed information may be warranted from more 

established programs and larger Phase I MS4s. 

Because stormwater is a component in many different program areas, it can often be difficult to get 

an accurate accounting of costs. For example, inspection staff may have multiple responsibilities in 

addition to stormwater inspections. Is it appropriate to count an entire inspector’s time (i.e. fulltime equivalent (FTE)) as a stormwater cost if the inspector is also doing building inspections? Also, 

some permittees count street sweeping as a stormwater compliance cost, while others consider 

their street sweeping costs as an aesthetic or air quality cost. Permittees should provide a detailed 

breakdown of costs, along with background or additional discussion so the permit writer knows 

what the costs include. 

Chapter 1: Establishment of the Stormwater Management Program 17
CHAPTER 2: PUBLIC EDUCATION AND OUTREACH/PUBLIC 

INVOLVEMENT

Introduction 

The Phase II Regulations require MS4 permittees to develop 

programs to educate the public about the impact of stormwater 

discharges on local waterways and the steps that citizens, 

businesses, and other organizations can take to reduce the 

contamination of stormwater (40 CFR 122.34(b)(1),(2)). Phase I 

MS4 permittees were also required to describe their proposed 

public education programs as part of their initial permit application, 

but the regulations are not as specific as Phase II. (See 40 CFR 

122.26(d)(2)(iv) (B), (D)(4) and (A)(6)). 

As the public gains a greater understanding of the benefits of 

stormwater management, an MS4 is likely to gain more support for the SWMP (including financial 

support) and increased compliance with the applicable regulatory requirements as the public 

understands how their actions impact water quality. Education and awareness programs help change 

human behavior with respect to reducing the amount of pollution generated from stormwater sources 

within the MS4 system. In addition to education, encouraging public participation in local stormwater 

programs can lead to program improvement as well as enabling people to identify and report a 

pollution-causing activity, such as spotting an illicit discharge. 

2.1 Developing a Comprehensive Stormwater Education/Outreach 

Program 

Example Permit Provision 

2.1.1 The permittee must: 

a. Continue to implement, and revise if necessary within [specify the time when the 

development of the program must be completed, e.g., within the first year after 

permit issuance], a comprehensive stormwater education/outreach program. 

The program must, at a minimum: 

1. Define the goals and objectives of the program based on at least three high 

priority, community-wide issues (e.g. reduction of nitrogen in discharges 

from the MS4, promoting pervious techniques used in the MS4); 

2. Identify and analyze the target audience(s); 

3. Create an appropriate message(s) based on at least three targeted 

residential issues and three targeted industrial/commercial issues from the 

suggested list below (or three issues deemed more appropriate to the MS4):

Included Concepts

► Developing a 

comprehensive 

stormwater education/ 

outreach program 

► Involving the public in 

planning and 

implementing the SWMP 

Chapter 2: Public Education and Outreach/Public Involvement 18 
MS4 Permit Improvement Guide 

Residential Community

 Residential car washing and auto 

maintenance control measures 

 Off-pavement automobile parking 

 Home and garden care activities 

(pesticides, herbicides, and fertilizers) 

 Disposal of household hazardous waste 

(e.g. paints, cleaning products) 

 Snow removal activities 

 Using techniques that keep water 

onsite and/or reduce imperviousness 

(rain barrels, rain gardens, porous 

pavers, permeable concrete, porous 

asphalt, etc.) 

 Litter prevention 

 Importance of native vegetation for 

preventing soil erosion 

 Public reporting of water quality issues 

 Community activities (monitoring 

programs, environmental protection 

organization activities, etc.) 

 Pet and other animal wastes 

Industrial/Commercial Community

 Automobile repair and maintenance 

Control measures 

 Control measure installation and 

maintenance 

 Lawful disposal of vacuum truck and 

sweeping equipment waste 

 Pollution prevention and safe alternatives 

 Snow removal activities 

 Using techniques that keep water onsite 

and/or reduce imperviousness (rain 

barrels, rain gardens, porous pavers, 

permeable concrete, porous asphalt, etc.) 

 Equipment and vehicle maintenance and 

repair 

 Importance of good housekeeping (e.g. 

sweeping impervious surfaces instead of 

hosing) 

 Illicit discharge detection and elimination 

observations and follow-up during daily 

work activities 

 Water quality impacts associated with 

land development (including new 

construction and redevelopment) 

 Water quality impacts associated with 

road resurfacing and repaving 

4. Develop appropriate educational materials (e.g. the materials can utilize 

various media such as printed materials, billboard and mass transit 

advertisements, signage at select locations, radio advertisements, television 

advertisements, websites); 

5. Determine methods and process of distribution; 

6. Evaluate the effectiveness of the program; and 

7. Utilize public input (e.g., the opportunity for public comment, or public 

meetings) in the development of the program. 

b. During the term of the permit, the permittee must distribute the educational 

materials, using whichever methods and procedures determined appropriate by 

the permittee, in such a way that is designed to convey the program’s message 

to [insert percentage or other appropriate numeric threshold, e.g., 20%] of the 

target audience each year. 

c. Within [insert deadline, e.g., within the permit term], the permittee must assess 

changes in public awareness and behavior resulting from the implementation of 

the program such as using a statistically valid survey and modify the 

education/outreach program accordingly. 

Chapter 2: Public Education and Outreach/Public Involvement 19
MS4 Permit Improvement Guide 

d. The permittee must assess its stormwater education/outreach program annually 

as specified in Part 8.3 of this permit. The permittee must adjust its educational 

materials and the delivery of such materials to address any shortcomings found 

as a result of this assessment. 

e. Written procedures for implementing this program must be incorporated into 

the SWMP document. 

Example Permit Requirement Rationale for the Fact Sheet 

Without a focused and comprehensive program, outreach and education efforts will likely be 

poorly coordinated and possibly ineffective. The permit the permittee to develop an 

education/outreach program that addresses the six steps listed and also found in EPA’s Getting 

In Step: A Guide to Effective Outreach in Your Watershed 

(www.epa.gov/watertrain/gettinginstep/). This guide explains the steps in developing an 

outreach plan, presents information on creating outreach materials, and provides tips in 

working with the media. The permittee is encouraged to follow this guide in developing its 

outreach strategy. 

The public education and outreach program must be tailored and targeted to specific water 

quality issues of concern in the relevant community. These community-wide and targeted 

issues must then guide the development of the comprehensive outreach program, including the 

creation of appropriate messages and educational materials. The permit includes a list of 

potential residential and commercial issues, but the permittee may also choose other issues 

that contribute significant pollutant loads to stormwater. 

The permittee is encouraged to use existing public educational materials in its program. 

Examples of public educational materials for stormwater are available at EPA’s Nonpoint Source 

Outreach Toolbox (www.epa.gov/nps/toolbox). The permittee is also encouraged to leverage 

resources with other agencies and municipalities with similar public education goals. 

Finally, the underlying principle of any public education and outreach effort is to change 

behaviors. The permittee must develop a process to assess how well its public education and 

outreach programs is changing public awareness and behaviors and to determine what changes 

are necessary to make its public education program more effective. This assessment of public 

education programs is typically conducted via phone surveys, but other assessment methods 

that quantify results can be used. The permittee is encouraged to use a variety of assessment 

methods to evaluate the effectiveness of different public education activities. The permit 

requires that the first evaluation assessment be conducted before the final year of the 

permittee’s coverage under this permit, before the next permit is issued. The allows the 

permittee to make changes as appropriate before the next permit application is due, EPA’s 

Getting In Step: A Guide to Effective Outreach in Your Watershed 

(www.epa.gov/watertrain/gettinginstep/) can provide useful information on setting up and 

conducting the evaluations. 

Chapter 2: Public Education and Outreach/Public Involvement 20
MS4 Permit Improvement Guide 

Recommendations for the Permit Writer 

EPA recommends that the requirement to identify high priority community-wide issues and targeted 

issues be set at least 3 to 6 months before the stormwater education/outreach program is to be 

implemented, so the permitting authority can review the issues and provide any feedback before 

the plan is completed. 

The permit can be a means for increasing public awareness and understanding of stormwater 

impacts on local watersheds, including high quality watersheds that need protecting. EPA 

recommends that the permit writer consider requiring permittees to identify and describe issues, 

such as specific pollutants, the sources of those pollutants, impacts on biology, and the physical 

attributes of stormwater runoff, in their education/outreach program, which affect local 

watershed(s). Where applicable, the education/outreach program should identify and describe high 

quality watersheds in need of protection and the issues that may threaten the quality of these 

waters. 

The list in Part 2.1.1.a(3) is not all-inclusive. Therefore, EPA recommends that the permit be written 

to allow the permittee to indentify priority issue(s) not listed that may contribute a significant 

pollutant load to stormwater. For Phase I, individual permits, it may be appropriate for the permit 

writer to specify the priority issues based on known issues, monitoring data, historical trends, etc. 

Phase II general permits will likely need to allow for more flexibility in selecting priority issues. 

In addition, the permit writer will need to consider that DOTs and other “non-traditional” MS4s will 

likely have different priority concerns than the ones identified in the categories above. In fact, the 

categories (residential and commercial/industrial) may also need to be changed. In these instances, 

the permit writer may want to consider having the non-traditional permittees work together with 

any local government MS4s in their area to maximize the program and cost effectiveness of the 

outreach. 

The permit writer may consider specifying the mechanism the permittee is required to use to 

measure the awareness of and behavior related to issues concerning stormwater runoff by the 

general public, or targeted audiences within the general public. Examples of evaluations could 

include: 

 Direct Evaluations  Interviews 

 Surveys  Review of media clippings 

 Tracking the number of attendees  Tracking the number of stormwater-related 

calls/emails/letters received 

Permit writers should consider whether it is appropriate to require a baseline assessment of the 

public’s awareness of stormwater issues, for example in the second year of the permit term, so that 

comparisons may be drawn in reference to the baseline. This would likely require the permittee to 

conduct two assessments in the first permit term that the assessment is required. 

Chapter 2: Public Education and Outreach/Public Involvement 21
MS4 Permit Improvement Guide 

2.2 Involving the Public in Planning and Implementing the SWMP 

Example Permit Provision 

2.2.1 The permittee is required to involve the public in the planning and implementation 

of activities related to the development and implementation of the SWMP. At a 

minimum, the permittee must: 

a. Establish a citizen advisory group or utilize existing citizen organizations. The 

permittee may establish a stand-alone group or utilize an existing group or 

process. The advisory group must consist of a balanced representation of all 

affected parties, including residents, business owners, and environmental 

organizations in the MS4 area and/or affected watershed. The permittee must 

invite the citizen advisory group to participate in the development and 

implementation of all parts of the community’s SWMP. 

b. Create opportunities for citizens to participate in the implementation of 

stormwater controls (e.g., stream clean-ups, storm drain stenciling, volunteer 

monitoring, and educational activities). 

c. Ensure the public can easily find information about the permittee’s SWMP. 

2.2.2 Written procedures for implementing this program must be incorporated into the 

SWMP document. 

Example Permit Requirement Rationale for the Fact Sheet 

Stormwater management programs can be greatly improved by involving the community 

throughout the entire process of developing and implementing the program. Involving the 

public benefits both the permittee itself as well as the community. B y listening to the public’s 

concerns and coming up with solutions together, the permittee will gain the public’s support 

and the community will become invested in the program. The permittees will likewise gain even 

more insight into the most effective ways to communicate their messages. 

This permit requires the involvement of the public, which includes a citizen advisory group or 

process to solicit feedback on the stormwater program, and opportunities for citizens to 

participate in implementation of the stormwater program. The citizen advisory group should 

meet with the local land use planners and provide input on land use code or ordinance updates 

so that land use requirements incorporate provisions for better management of stormwater 

runoff and watershed protection. Public participation in implementation of the stormwater 

program can include many different activities such as stream clean-ups, storm drain markings, 

and volunteer monitoring. 

Permittees are encouraged to work together with other entities that have an impact on 

stormwater (for example, schools, homeowner associations, DOTs, other MS4 permittees). 

Permittees are also encouraged to use existing advisory groups or processes in order to 

implement these public involvement requirements. 

Chapter 2: Public Education and Outreach/Public Involvement 22
MS4 Permit Improvement Guide 

Chapter 2: Public Education and Outreach/Public Involvement 23

Recommendations for the Permit Writer 

Especially for Phase I permittees, permit writers may consider requiring more specific information 

such as requiring at least one contact that the public can reach (including phone number and/or email address) be clearly posted on the website. The contact may be a general contact or a specific 

person. The permitting authority may want the MS4 to have a mechanism for the public to 

comment year round, not just at public meetings. This could be facilitated by a webpage and email 

or a stormwater hotline. 

Some Phase II permittees may find it more difficult to establish and maintain a formal citizen 

advisory group simply because they tend to have smaller populations. The permit writer may want 

to provide flexibility for the Phase II permittees to utilize the public involvement mechanism which 

best suits their individual community. For example, groups which are already involved with other 

aspects of municipal governance or established events where input could be solicited (i.e. farmers 

markets, festivals) may serve to meet the objective of this section. 
CHAPTER 3: ILLICIT DISCHARGE DETECTION AND ELIMINATION

Introduction 

Phase I (see 40 CFR 122.26 (d)(1)(v)(B) and (d)(1)(iv)(B)) and Phase II 

stormwater management programs (see 40 CFR 122.26(d)(2)(iv)(B)) 

are required to address illicit discharges into the MS4 system. An 

illicit discharge is defined as any discharge to a municipal separate 

storm sewer system that is not composed entirely of stormwater, 

except allowable discharges pursuant to an NPDES permit (40 CFR 

122.26(b)(2)). In addition to requiring permittee to have the legal 

authority to prohibit non-stormwater discharges from entering storm 

sewers (CWA Section 402(p)(3)(B)) (see Chapter I), MS4 permits must 

also require the development of a comprehensive, proactive Illicit 

Discharge Detection Elimination (IDDE) program. 

An effective IDDE program is more than just a program to respond to 

complaints about illicit discharges or spills. Permittees must proactively 

seek out illicit discharges, or activities that could result in discharges, 

such as illegal connections to the storm sewer system, improper 

disposal of wastes, or dumping of used motor oil or other chemicals. 

In order to trace the origin of a suspected illicit discharge or connection, the permittee must have an 

updated map of the storm drain system and a formal plan of how to locate illicit discharges and how to 

respond to them once they are located or reported. The permittee must provide a mechanism for public 

reporting of illicit discharges and spills, as well as an effective way for staff to be alerted to such reports. 

Regular field screening of outfalls for non-stormwater discharges needs to occur in areas determined to 

have a higher likelihood for illicit discharges and illegal connections. Proper investigation and enforcement 

procedures must be in place to eliminate the sources of the discharges, as well. Finally, in order for the 

permittee to adequately detect and eliminate sources of illicit discharges, both field and office staff must 

be properly trained to recognize and report the discharges to the appropriate parties. 

EPA recommends that permittees refer to the Center for Watershed Protection’s guide on Illicit 

Discharge Detection and Elimination (IDDE): A Guidance Manual for Program Development and 

Technical Assistance (IDDE Manual, available at www.cwp.org) when developing an IDDE program. 

3.1 IDDE Program Development 

Example Permit Provision 

3.1.1 The permittee must continue to implement a program to detect, investigate, and 

eliminate non-stormwater discharges (see Part 1.2.2), including illegal dumping, into 

its system. The IDDE program must include the following: 

Included Concepts

► IDDE program 

development 

► MS4 mapping 

► Identification of priority 

areas 

► Field screening 

► IDDE source 

investigations and 

elimination 

► Public reporting of nonstormwater discharges 

and spills 

► Illicit discharge education 

and training

Chapter 3: Illicit Discharge Detection and Elimination 24 
MS4 Permit Improvement Guide 

a. An up-to-date storm sewer system map (see Part 3.2). 

b. Procedures for identifying priority areas within the MS4 likely to have illicit 

discharges, and a list of all such areas identified in the system (see Part 3.3) 

c. Field screening to detect illicit discharges (see Part 3.4) 

d. Procedures for tracing the source of an illicit discharge (see Part 3.5) 

e. Procedures for removing the source of the discharge (see Part 3.5) 

f. Procedures for program evaluation and assessment (see Part 8.3) 

g. Procedures to prevent and correct any on-site sewage disposal systems that 

discharge into the MS4. 3

3.1.2 In implementing the IDDE program, the permittee may conduct such investigations, 

contract for investigation, coordinate with storm drain investigation activities of 

others, or use any combination of these approaches. 

3.1.3 For non-traditional MS4 permittees, if illicit connections or illicit discharges are 

observed related to another operator’s municipal storm sewer system then the 

permittee must notify the other operator within [insert applicable deadline, e.g., 

within 48 hours] of discovery. 

3.1.4 If another operator notifies the permittee of an illegal connection or illicit discharge 

to the municipal separate storm sewer system then the permittee must follow the 

requirements specified in Part 3.5.4. 

3.1.5 Written procedures for implementing this program, including those components 

described in Parts 3.1 – 3.7 must be incorporated into the SWMP document. 

Example Permit Requirement Rationale for the Fact Sheet 

EPA stormwater regulations define "illicit discharge" as "any discharge to a municipal separate 

storm sewer that is not composed entirely of stormwater" except discharges resulting from fire 

fighting activities and discharges from NPDES permitted sources (see 122.26(b)(2)). The 

applicable regulations state that the following non-stormwater discharges may be allowed if 

they are not determined to be a significant source of pollutants to the MS4 : water line flushing, 

landscape irrigation, diverted stream flows, rising ground waters, uncontaminated ground water 

infiltration (as defined at 40 CFR 35.2005(20)), uncontaminated pumped ground water, 

discharges from potable water sources, foundation drains, air conditioning condensation, 

irrigation water, springs, water from crawl space pumps, footing drains, lawn watering, 

individual residential car washing, flows from riparian habitats and wetlands, dechlorinated 

swimming pool discharges, and street wash water. If, however, these discharges are 

determined to be a significant source of pollution then they are prohibited. 

Examples of common sources of illicit discharges in urban areas include apartments and homes, 

car washes, restaurants, airports, landfills, and gas stations. These so called "generating sites" 

discharge sanitary wastewater, septic system effluent, vehicle wash water, washdown from 

 

3

 Vermont Phase II General Permit (www.vtwaterquality.org/stormwater/htm/sw_ms4.htm) 

Chapter 3: Illicit Discharge Detection and Elimination 25
MS4 Permit Improvement Guide 

grease traps, motor oil, antifreeze, gasoline and fuel spills, among other substances. Although 

these illicit discharges can enter the storm drain system in various ways, they generally result 

from either direct connections (e.g., wastewater piping either mistakenly or deliberately 

connected to the storm drains) or indirect connections (e.g., infiltration into the storm drain 

system, spills, or "midnight dumping"). Illicit discharges can be further divided into those 

discharging continuously and those discharging intermittently. 

One way of locating these dry weather discharges is to perform field screening of outfalls. If no 

rain has occurred prior to the screening then it is likely that any flow observed at an outfall is 

either groundwater or an illicit discharge. It is important to utilize resources effectively and to 

target field screening activities in priority areas that are the most common sources of illicit 

discharges. For example, municipalities with older neighborhoods should prioritize those areas 

for targeted investigation due to the likelihood of cross connections with the sanitary sewer. 

Older parts of the storm drain system may also be deteriorating and require repair or 

replacement. 

In addition, it is important that permittees establish clear policies and procedures for tracing 

and eliminating illicit discharges to ensure that individual incidents are addressed consistently. 

These policies should include procedures to notify neighboring localities if a discharge is 

discovered either originating on or discharging to the neighboring storm sewer system. 

Additional information is available in the Center for Watershed Protection’s IDDE Manual.

Recommendations for the Permit Writer 

In some instances the permit writer may choose to include more specific requirements. For 

example, if the priority areas are already known, then Part 3.1.1.a may be more specifically worded. 

In addition, regulations governing Phase I MS4 permits have somewhat different requirements 

including specific field screening procedures (40 CFR 122.26(d)(1)(iii)(D) and 122.26(d)(2)(iii)) and a 

program to detect and remove illicit discharges and improper disposal into the storm sewer (40 CFR 

122.26(d)(2)(iv)(B). 

3.2 MS4 Mapping 

Example Permit Provision 

3.2.1 The permittee must maintain an up-to-date and accurate storm sewer system map. 

a. The storm sewer system map must show the following, at a minimum: 

1. The location of all MS4 outfalls and drainage areas contributing to those 

outfalls that are operated by the permittee, and that discharge within the 

permittee’s jurisdiction to a receiving water 

2. The location (and name, where known to the permittee) of all waters 

receiving discharges from those outfall pipes. Each mapped outfall must be 

given an individual alphanumeric identifier, which must be noted on the 

map. When possible, the outfalls must be located using a geographic 

Chapter 3: Illicit Discharge Detection and Elimination 26
MS4 Permit Improvement Guide 

position system (GPS) and photographs should be taken to provide baseline 

information and track operation & maintenance needs over time.4

3. Priority areas identified under Part 3.3 

4. Field screening stations identified under Part 3.4.2.a 

b. A copy of the storm sewer system map must be available onsite for review by 

the permitting authority. 

Example Permit Requirement Rationale for the Fact Sheet

In order to trace the origin of a suspected illicit discharge or connection, the permittee must 

have an up-to-date map of its storm drain system. This is critical in order to isolate the potential 

source of the non-stormwater discharges and the areas of potential impact. Ideally, the 

information would be available as a geographic information system (GIS) layer in a geolocational database, however, paper maps are sufficient providing they have the necessary 

reference information. 

The permit primarily requires the mapping of outfalls, drainage areas contributing to those 

outfalls, and receiving waters. The municipal facility inventory created to comply with the 

pollution prevention/good housekeeping requirements (see Part 6.1) must also be included 

either on this sewer system map or on a separate MS4 map. 

Recommendations for the Permit Writer 

Both Phase I and Phase II regulations require permittees to develop a map indicating outfalls and 

the waters that receive the MS4 discharges. This map is to be used to identify priority areas that 

have a reasonable potential for illicit discharges. The mapping requirements should be adjusted 

based on any existing mapping of the MS4 that has already been completed. For example, Phase I 

mapping should have been initiated during the initial permit application process. This map should 

not be static, however, since it would need to be updated as development patterns change and new 

collection and discharge components of the MS4 are added. The mapping requirement could be 

supplemented by adding a requirement to “modify existing maps to clearly identify all receiving 

waters.” 

3.3 Identification of Priority Areas 

Example Permit Provision 

3.3.1 The permittee must continue to identify the following as priority areas [insert areas 

that may be more applicable to the jurisdiction]: 

a. Areas with older infrastructure that are more likely to have illicit connections; 

 

4

 New Jersey Phase II General Permit (www.state.nj.us/dep/dwq/pdf/Tier_A_final.pdf), with modifications 

Chapter 3: Illicit Discharge Detection and Elimination 27
MS4 Permit Improvement Guide 

b. Industrial, commercial, or mixed use areas; 

c. Areas with a history of past illicit discharges; 

d. Areas with a history of illegal dumping; 

e. Areas with onsite sewage disposal systems; 

f. Areas with older sewer lines or with a history of sewer overflows or crossconnections; and 

g. Areas upstream of sensitive waterbodies. 

3.3.2 The permittee must document the basis for its selection of each priority area and 

create a list of all priority areas identified in the system. This priority area list must 

be updated [insert frequency, e.g., annually] to reflect changing priorities and be 

available for review by the permitting authority. 

Example Permit Requirement Rationale for the Fact Sheet

The permit requires an evaluation of the permittee’s neighborhoods and land uses to identify 

areas that are more likely to have illicit discharges. These areas must be prioritized for more 

frequent screening and investigations. Each permittee will have a different set of priority areas: 

newer communities with modern infrastructure are less likely to have sewer cross-connections 

and illegal connections to the storm drain system, whereas towns with rural areas may place an 

emphasis on illegal dumping and onsite sewage disposal systems. Prioritization must be based 

not only on land use but also on prior history and frequency of problems. 

The identification of priority areas must include “hotspots” or areas where dumping, spills, or 

other illicit discharges are a common occurrence. These hotspots will help identify potential 

field screening locations and may help target educational activities. For example, if evidence of 

motor oil dumping is found quite frequently and traced to the same apartment complex, 

information about motor oil disposal could be distributed to residents in response. 

Recommendations for the Permit Writer 

Phase I permittees should have been documenting information regarding high priority areas for 

several permit terms. In these instances the permit writer should require the permittee to 

continually evaluate and update the priority areas as development patterns change or new 

“hotspot” areas are found. If the permit writer has information regarding priority areas which are 

specific to the Phase I permittee (e.g. certain high priority watersheds or land use types which 

typically discharge a pollutant of concern) then those specific areas should be specified as high 

priority. 

Chapter 3: Illicit Discharge Detection and Elimination 28
MS4 Permit Improvement Guide 

3.4 Field Screening 

Example Permit Provision 

3.4.1 The permittee must continue to implement and revise if necessary within [specify 

deadline for completion] a written dry weather field screening and analytical 

monitoring procedures to detect and eliminate illicit discharges to the MS4. These 

procedures must be included as part of the IDDE program, and incorporated into the 

permittee’s SWMP document. Dry weather field screening and analytical monitoring 

consists of (1) field observations; (2) field screening monitoring; and (3) analytical 

monitoring at selected stations. 

3.4.2 Conduct dry weather field screening and analytical monitoring. At a minimum, the 

permittee must: 

a. Identify a minimum of [specify number] stations within the priority areas it 

identified in Part 3.3.1 at which field screening and analytical monitoring will 

take place. In addition, if the permittee is made aware of non-stormwater 

discharges that occur during the permit term outside of the priority areas, the 

permittee must include field screening stations in those areas; 

b. Conduct dry weather field screening and analytical monitoring at each station 

identified above at least once [insert timeframe for dry part of year, or specify 

annually]. 

c. Sample runoff according to requirements outlined in (1) and (2) below if flow or 

ponded runoff is observed at a field screening station and there has been at least 

seventy-two (72) hours of dry weather. The permittee must also record general 

information such as time since last rain, quantity of last rain, site descriptions (e.g., 

conveyance type, dominant watershed land uses), flow estimation (e.g., width of 

water surface, approximate depth of water, approximate flow velocity, flow rate), 

and visual observations (e.g., odor, color, clarity, floatables, deposits/stains, 

vegetation condition, structural condition, and biology). 

1. Field screening requirements: The permittee is required to conduct a field 

screening analysis for the following constituents. Samples must be collected 

and analyzed consistent with the procedures required by 40 CFR Part 136. 

 [insert specific indicator pollutants that the permittee is required to monitor 

for.]

2. Analytical monitoring requirements: In addition to field screening, the 

permittee is required to collect samples for analytical laboratory analysis of 

the following constituents for a minimum of [insert percentage] of the 

samples taken. Samples must be collected and analyzed consistent with the 

procedures required by 40 CFR Part 136. 

 [insert specific pollutants of concern that the permittee is required to 

monitor for] 

3. Develop benchmark concentration levels for dry weather field screening and 

analytical monitoring results whereby exceedance of the benchmark will 

Chapter 3: Illicit Discharge Detection and Elimination 29
MS4 Permit Improvement Guide 

require follow-up investigations to be conducted to identify and eliminate 

the source causing the exceedance of the benchmark. 

d. Conduct a follow-up investigation under Part 4.5 if the benchmarks associated 

with the constituents listed above in Part 3.4.2.c(1) and (2) are exceeded; and 

e. Make and record all applicable observations and select another station from the 

list of alternate stations for monitoring if, after two subsequent field screening 

tests have been completed, the field screening station is dry (i.e., no flowing or 

ponded runoff). 

3.4.3 The permittee must assess its IDDE program every [specify deadline for completion, 

e.g., once per permit term] to determine if updates are needed. Where updates are 

found to be necessary, the permittee must make such changes [insert deadline for 

finalizing changes]. 

Example Permit Requirement Rationale for the Fact Sheet 

The permit requires the development of a dry weather field screening and analytical monitoring 

program. The program must identify stations (e.g., outfalls) within the identified “priority 

areas” where the field screening will be conducted. At a frequency set by the permitting 

authority, the permittee must screen outfalls during dry weather and, if flow or ponded water is 

observed, collect a sample for field screening and analytical monitoring. 

Visually screening outfalls during dry weather and conducting field tests, where flow is 

occurring, of selected chemical parameters as indicators of the discharge source will assist 

permittees in determining the source of illicit discharges. For example, the presence of 

surfactants is an indicator that sewage could be present in the discharge (e.g., soaps being 

discharged into sewer system as an indicator that wastewater is being discharged). Specific 

conductivity, fluoride and/or hardness concentration, ammonia and/or potassium 

concentration, surfactant and/or fluorescence concentration, chlorine concentration, pH, and 

other chemicals may similarly be indicative of industrial sources. 

The permit requires the permittee to develop benchmarks for dry weather screening and 

analytical monitoring results. An exceedance of the benchmark concentration level indicates the 

need to conduct a follow-up investigation. The results will help the permittee narrow down the 

possible sources causing the benchmark to be exceeded so that they can then be eliminated. 

This is a common protocol to trigger additional monitoring and/or implementation of BMPs at 

stormwater discharges (e.g. MSGP has sector-specific benchmark monitoring requirements). 

Recommendations for the Permit Writer 

There are many options for field screening programs available to the permit writer that will meet 

the requirements of the regulations. Phase I regulations require that permittees conduct initial field 

screening of the entire MS4 during the permit application process as well as on-going field screening 

activities during the life of the permit. Based on this historical information and data, permit writers 

may want to specify in Phase I individual permits which priority areas must be screened. They may 

Chapter 3: Illicit Discharge Detection and Elimination 30
MS4 Permit Improvement Guide 

also want to specify how many outfalls or what percentage of the outfalls should be inspected 

during the permit term. 

In addition, for new Phase II permittees, permit writers may want to require screening of all priority 

areas during the first permit term and then require on-going screening in the areas where illicit 

discharges were identified. 

This permit language includes analytical monitoring at dry weather field screening locations. The 

monitoring required during field screening (Part 3.4.2.c.1.) should include appropriate indicator 

pollutants, i.e. pollutants that will indicate the presence of some sort of illicit discharge. For 

example, Phase II NPDES regulations suggest sampling for specific conductivity, ammonia, surfactant 

and/or fluorescence concentration, pH and other chemicals indicative of industrial sources. 

Permit writers should select the additional pollutants to be monitored based upon specific 

pollutants of concern for the receiving water(s) and/or specific indicator pollutants which can assist 

the MS4 in the location of particular discharges of concern and the potential water quality impact of 

the discharge. For example, the Phase I San Diego MS4 Permit requires that permittees monitor the 

following parameters during field screening: total hardness, oil and grease, diazinon and 

chlorpyrifos, cadmium (dissolved), lead (dissolved), zinc (dissolved), copper (dissolved), 

Enterococcus bacteria, total coliform bacteria, and fecal coliform bacteria. 

Permit writers should encourage or even require permittees to use the CWP IDDE Manual and/ or 

EPA’s 2008 Multi-Sector General Permit (www.epa.gov/npdes/stormwater/msgp) to develop 

benchmarks for each parameter. 

In the IDDE Manual it is strongly recommended that benchmarks be developed specifically for each 

area. As an example, the IDDE Manual lists the following benchmark concentrations (Table 3-1) to 

identify industrial discharges: 

Table 3-1. Benchmark concentrations to identify Industrial Discharges 

(from CWP IDDE Manual, Table 45) 

Indicator Parameter Benchmark Concentration 

Ammonia >= 50 mg/L 

Color >= 500 units 

Conductivity >= 2,000 μS/cm 

Hardness <= 10 mg/L as CaCO3 or >= 2,000 mg/L as CaCO3 

pH <= 5 

Potassium >= 20 mg/L 

Turbidity >= 1,000 NTU 

For comparison purposes, the chemical fingerprint for different flow types in Alabama is presented 

in Table 3-2. The chemical fingerprint for each flow type can differ regionally, so permittees should 

develop their own “fingerprint” library by sampling each flow type. 

Table 3-2. Comparative “Fingerprint” (Mean Values) of Flow Types (from CWP IDDE Manual, 

Table 1) 

Flow Type Hardness 

(mg/L as CaCO3) 

NH3 (mg/L) Potassium 

(mg/L) 

Conductivity 

(μS/cm)

Fluoride 

(mg/L) 

Detergents 

(mg/L) 

Sewage 50 (0.26) 25 (0.53) 12 (0.21) 1215 (0.45) 0.7 (0.1) 9.7 (0.17) 

Septage 57 (0.36) 87 (0.4) 19 (0.42) 502 (0.42) 0.93 (0.39) 3.3 (1.33) 

Chapter 3: Illicit Discharge Detection and Elimination 31
MS4 Permit Improvement Guide 

Table 3-2. Comparative “Fingerprint” (Mean Values) of Flow Types (from CWP IDDE Manual, 

Table 1) 

Laundry 

Washwater 

45 (0.33) 3.2 (0.89) 6.5 (0.78) 463.5 (0.88) 0.85 (0.4) 758 (0.27) 

Car Washwater 71 (0.27) 0.9 (1.4) 3.6 (0.67) 274 (0.45) 1.2 (1.56) 140 (0.2) 

Plating Bath 

(Liquid Industrial 

Waste) 

14330 (0.32) 66 (0.66) 1009 (1.24) 10352 (0.45) 5.1 (0.47) 6.8 (0.68) 

Radiator Flushing 

(Liquid Industrial 

Waste) 

5.6 (1.88) 26 (0.89) 2801 (0.13) 3280 (0.21) 149 (0.16) 15 (0.11) 

Tap Water 52 (0.27) <0.06 (0.55) 1.3 (0.37) 140 (0.07) 0.94 (0.07) 0 (NA) 

Groundwater 38 (0.19) 0.06 (1.35) 3.1 (0.55) 149 (0.24) 0.13 (0.93) 0 (NA) 

Landscape 

Irrigation 

53 (0.13) 1.3 (1.12) 5.6 (0.5) 180 (0.1) 0.61 (0.35) 0 (NA) 

The number in parentheses after each concentration is the Coefficient of Variation. 

Source: Robert Pitt data from CWP IDDE Manual 

The permit writer may also want to require the permittee to analyze a certain number of discharge 

samples to characterize the concentration of certain pollutants in the different drainage areas. This 

characterization sampling would be in addition to any characterization sampling completed for the 

Phase I permit application. This type of sampling would not necessarily aid in the elimination of the 

source of the discharge, however, the data would be useful in characterizing the discharge from the 

MS4. 

For those areas that have ponding or flow during dry weather, permit writers may consider allowing 

permittees the flexibility to look for indicators of an illicit discharge before conducting water quality 

tests due to baseline flow (e.g. baseflow, groundwater flow, irrigation return flows) in certain areas. 

In these cases, permit writers could require that sensory indicators (i.e. odor, color, turbidity, and 

floatables) be evaluated. 

For additional guidance on field screening, the IDDE Manual describes an outfall reconnaissance 

inventory (ORI) to assess outfalls and conduct indicator monitoring to help identify illicit discharges. 

Regardless of the field screening scheme, it is also very important to emphasize in the permit 

conditions that monitoring must be done in compliance with 40 CFR 136. 

3.5 IDDE Source Investigation and Elimination 

Example Permit Provision 

3.5.1 The permittee is required to develop written procedures for conducting 

investigations into the source of all identified illicit discharges, including approaches 

to requiring such discharges to be eliminated. 

3.5.2 Minimum Investigation Requirements – At a minimum, the permittee is required to 

conduct an investigation(s) to identify and locate the source of any continuous or 

Chapter 3: Illicit Discharge Detection and Elimination 32
MS4 Permit Improvement Guide 

intermittent non-stormwater discharge within [specify time period] of becoming 

aware of the illicit discharge. 

a. Illicit discharges suspected of being sanitary sewage and/or significantly 

contaminated must be investigated first. 

b. Investigations of illicit discharges suspected of being cooling water, wash water, 

or natural flows may be delayed until after all suspected sanitary sewage and/or 

significantly contaminated discharges have been investigated, eliminated and/or 

resolved. 

c. The permittee must report immediately the occurrence of any dry weather flows 

believed to be an immediate threat to human health or the environment to 

[insert state water quality emergency contact phone number]. 

d. The permittee must track all investigations to document at a minimum the date(s) 

the illicit discharge was observed; the results of the investigation; any follow-up 

of the investigation; and the date the investigation was closed. 

3.5.3 Determining the Source of the Illicit Discharge –The permittee is required to 

determine and document through its investigations, carried out in Part 3.5.1, the 

source of all illicit discharges. If the source of the illicit discharge is found to be a 

discharge authorized under [insert NPDES discharge permit reference] of an NPDES 

permit, no further action is required. 

a. If an illicit discharge is found, but within six (6) months of the beginning of the 

investigation neither the source nor the same non-stormwater discharge has 

been identified/observed, then the permittee must maintain written 

documentation for review by the permitting authority. 

b. If the observed discharge is intermittent, the permittee must document that a 

minimum of three (3) separate investigations were made to observe the 

discharge when it was flowing. If these attempts are unsuccessful, the Permittee 

must maintain written documentation for review by the permitting authority. 

However, since this is an ongoing program, the Permittee should periodically 

recheck these suspected intermittent discharges.5

3.5.4 Corrective Action to Eliminate Illicit Discharge – Once the source of the illicit 

discharge has been determined, the permittee must immediately notify the 

responsible party of the problem, and require the responsible party to conduct all 

necessary corrective actions to eliminate the non-stormwater discharge within 

[specify deadline]. Upon being notified that the discharge has been eliminated, the 

permittee must conduct a follow-up investigation and field screening, consistent 

with Part 3.4, to verify that the discharge has been eliminated. The permittee is 

required to document its follow-up investigation. The permittee may seek recovery 

and remediation costs from responsible parties consistent with Part 1.2, or require 

compensation for the cost of field screening and investigations. Resulting 

enforcement actions must follow the SWMP ERP. 

 

5

 New Jersey Phase II Permit (www.state.nj.us/dep/dwq/pdf/Tier_A_final.pdf) 

Chapter 3: Illicit Discharge Detection and Elimination 33
MS4 Permit Improvement Guide 

Example Permit Requirement Rationale for the Fact Sheet 

The Clean Water Act, section 402(p)(3)(B)(ii) requires MS4 permits to “effectively prohibit nonstormwater discharges into the storm sewers.” The permit implements this requirement, in 

part by requiring the development of procedures to investigate and eliminate illicit discharges. 

The permittee must develop a clear, step-by-step procedure for conducting the investigation of 

illicit discharges. The procedure must include an investigation protocol that clearly defines what 

constitutes an illicit discharge “case” and when a case is considered “closed.” In many 

circumstances, sources of intermittent, illicit discharges are very difficult to locate, and these 

cases may remain unresolved. The permit requires that each case be conducted in accordance 

with the SOPs developed to locate the source and conclude the investigation, after which the 

case may be considered closed. A standard operating procedure (SOP) document is required in 

order to provide investigators with guidance and any necessary forms to ensure that consistent 

investigations occur for every illicit discharge incident. 

Physical observations and field testing can help narrow the identification of potential sources of 

a non-stormwater discharge; however it is unlikely that either will pinpoint the exact source. 

Therefore, the permittee will need to perform investigations “upstream” to identify illicit 

connections to systems with identified problem outfalls. 

Once the source of the non-stormwater discharge is determined through investigation, 

corrective action is required to eliminate the problem source. Resulting enforcement actions 

must follow the SWMP ERP. The permittee may conduct remediation activities on its own, in 

which case the permittee must require compensation for any and all costs related to eliminating 

the non-stormwater discharge. Non-traditional MS4 permittees may be limited in their ability 

to seek recovery. 

Recommendations for the Permit Writer 

Both Phase I and Phase II regulations require permittees to develop a process to trace the source of 

illicit discharges and eliminate them. The regulations also state that appropriate enforcement 

procedures and actions must be included in this process. 

3.6 Public Reporting of Non-Stormwater Discharges and Spills 

Example Permit Provision 

3.6.1 The permittee must promote, publicize, and facilitate public reporting of illicit 

discharges or water quality impacts associated with discharges into or from MS4s 

through a central contact point, including phone numbers for complaints and spill 

reporting, and publicize to both internal permittee staff and the public. If 911 is 

selected, the permittee must also create, maintain, and publicize a staffed, nonemergency phone number with voicemail, which is checked daily. 

3.6.2 The permittee must develop a written spill/dumping response procedure, and a flow 

chart or phone tree, or similar list for internal use, that shows the procedures for 

responding to public notices of illicit discharges, the various responsible agencies 

Chapter 3: Illicit Discharge Detection and Elimination 34
MS4 Permit Improvement Guide 

and their contacts, and who would be involved in illicit discharge incidence 

response, even if it is a different entity other than the permittee. 

3.6.3 The permittee must conduct reactive inspections in response to complaints and 

follow-up inspections as needed to ensure that corrective measures have been 

implemented by the responsible party to achieve and maintain compliance.6

Example Permit Requirement Rationale for the Fact Sheet 

This provision serves to implement, in part, the statutory requirement that MS4 permits 

effectively prohibit non-stormwater discharges. Spills, leaks, sanitary sewer overflows, and illicit 

dumping or discharges can introduce a range of stormwater pollutants into the storm system. 

Prompt response to these occurrences is the best way to prevent or reduce negative impacts to 

waterbodies. The permittee must develop a spill response SOP that includes an investigation 

procedure similar to or in conjunction with the investigation SOP developed for illicit discharges 

in general (see Section 3.5). Often, a different entity might be responsible for spill response in a 

community (i.e. fire department), therefore, it is imperative that adequate communication 

exists between stormwater and spill response staff to ensure that spills are documented and 

investigated in a timely manner. 

A stormwater hotline can be used to help permittees become aware of and mitigate spills or 

dumping incidents. Spills can include everything from an overturned gasoline tanker to 

sediment leaving a construction site to a sanitary sewer overflow entering into a storm drain. 

Permittees must set up a hotline consisting of any of the following (or combination thereof): a 

dedicated or non-dedicated phone line, E-mail address, or website. 

Recommendations for the Permit Writer 

Spills which occur due to municipal staff activities are considered illicit discharges, but, spill 

prevention could also be addressed in the municipal operations/good-housekeeping portion of the 

permit as in this Guide (Chapter 6). 

Facilitating public reporting of illicit discharges is specifically required in the Phase I regulations and 

as a part of the plan to detect and address illicit discharge, EPA recommends that Phase II 

permittees also develop a venue to promote, publicize, and facilitate public reporting of these 

discharges. 

It is also noteworthy that smaller Phase II MS4s may utilize outside agency resources for spill 

response and/or they may use a neighboring locality. In this case, permittees will need to 

coordinate with these agencies to ensure appropriate spill response occurs and the necessary 

documentation is completed. 

 

6

 San Francisco Municipal Regional Stormwater permit 

(www.swrcb.ca.gov/sanfranciscobay/board_decisions/adopted_orders/2009/R2-2009-0074.pdf), with 

modifications 

Chapter 3: Illicit Discharge Detection and Elimination 35
MS4 Permit Improvement Guide 

Chapter 3: Illicit Discharge Detection and Elimination 36

3.7 Illicit Discharge Education & Training 

Example Permit Requirement 

3.7.1 The permittee must continue to implement a training program for all municipal field 

staff, who, as part of their normal job responsibilities, may come into contact with or 

otherwise observe an illicit discharge or illicit connection to the storm sewer system. 

Contact information, including the procedure for reporting an illicit discharge, must 

be included in the permittee’s fleet vehicles that are used by field staff. Training 

program documents must be available for review by the permitting authority. 

3.7.2 By no later than [insert applicable deadline, e.g., 6 months after permit 

authorization], the permittee must train all staff identified in Section 3.7.1 above on 

the identification of an illicit discharge or connection, and on the proper procedures 

for reporting and responding to the illicit discharge or connection. Follow-up 

training must be provided as needed to address changes in procedures, techniques, 

or staffing. The permittee must document and maintain records of the training 

provided and the staff trained. 7

Example Permit Requirement Rationale for the Fact Sheet 

The permit requires the permittee to train field staff, who may come into contact or observe 

illicit discharges, on the identification and proper procedures for reporting illicit discharges. 

Field staff to be trained may include, but are not limited to, municipal maintenance staff, 

inspectors, and other staff whose job responsibilities regularly take them out of the office and 

into areas within the MS4 area. Permittee field staff are out in the community every day and 

are in the best position to locate and report spills, illicit discharges, and potentially polluting 

activities. With proper training and information on reporting illicit discharges easily accessible, 

these field staff can greatly expand the reach of the IDDE program. 

Recommendations for the Permit Writer 

Permit writers may wish to require training of office staff (or all permittee staff), as well as field 

staff, as they can act as additional “eyes and ears” since they typically live in the community. The 

training should consist of how to identify illicit discharges and dumping, as well as the appropriate 

people to contact based on the type of discharge that is occurring. 

Existing permittees (Phase I and Phase II) may have been training staff for several permit terms. For 

this reason, the permit writer may want the permittee to focus on annual “refresher” trainings for 

existing staff and new employees within a certain time of their hire date. 

 

7

 Washington State Phase I Permit (www.ecy.wa.gov/programs/wq/stormwater/municipal/phaseIpermit/

MODIFIEDpermitDOCS/PhaseIpermitSIGNED.pdf) 
CHAPTER 4: CONSTRUCTION

Introduction 

MS4 permits must address construction-related requirements (and 

often more specific state requirements) found in the following 

Federal regulations – Phase I MS4 Regulations 40 CFR 

122.26(d)(2)(iv)(D) and Phase II MS4 Regulations 40 CFR 

122.34(b)(4). Specific Permit Requirements should vary based on 

state requirements, rainfall amounts or other site-specific factors, 

but, in general, the requirements imposed on MS4 permittees for 

stormwater management of discharges associated with 

construction activities consist of several common requirements. 

Permits must require that the permittee enact, to the extent 

allowed by State, Tribal or local law, an ordinance or other 

regulatory mechanism as part of the construction program that 

controls runoff from construction sites with a land disturbance of 

greater than or equal to one acre, including projects less than one 

acre that are part of a larger common plan of development or sale. 

As part of the ordinance or other regulatory mechanism, the 

permittee should provide commonly understood and legally binding 

definitions. These terms should be defined consistently across 

other related guidance and regulatory documents. Note that EPA’s 

recommended definitions addressing this requirement are included in Appendix B. 

Included Concepts

► Construction 

requirements and control 

measures 

► Construction site 

inventory 

► Construction plan review 

procedures 

► Construction site 

inspections and 

enforcement 

► MS4 staff training 

► Construction site operator 

education and public 

involvement 

Permits must require that MS4 permittees ensure that construction site operators select and implement 

appropriate erosion and sediment control measures to reduce or eliminate the impacts to receiving 

waters. The permit can require that permittees develop their own standards and specifications, but 

often it is preferable to require the permittees to utilize existing guidance that is approved by the 

permitting authority. 

The permit must require that the permittee establish review procedures for construction site plans to 

determine potential water quality impacts and ensure the proposed controls are adequate. These 

procedures must include the review of individual pre-construction site plans to ensure consistency with 

local sediment and erosion control requirements. In addition, the permit must include requirements for 

inspection and enforcement of erosion and sediment control measures once construction begins. 

Finally, Phase I MS4 permits must require the development of educational materials and training for 

construction site operators, and EPA recommends that training on stormwater controls for construction 

site operators be mandated in Phase II MS4 permits as well. Training should address site requirements 

for control measures, local stormwater requirements, enforcement activities, and penalties for noncompliance. 

Chapter 4: Construction 37 
MS4 Permit Improvement Guide 

4.1 Construction Requirements and Control Measures 

Example Permit Provision 

4.1.1 The permittee must continue to implement a program which requires operators of 

public or private “construction activities” to select, install, implement, and maintain 

stormwater control measures that comply with [Insert reference to documents 

including any and all applicable erosion and sediment control, pollution prevention, 

and other stormwater requirements, including applicable CGP, State, and local 

requirements.] “Construction activity” for this permit includes, at a minimum, all 

public and private construction sites that result in a total land disturbance of [insert 

disturbance threshold – either one or more acres or that result in a total land 

disturbance of less than one acre if part of a larger common plan or development or 

sale, or an alternative threshold that includes disturbances of less than one acre]. 

Written procedures for implementing this program, including the components 

described in Parts 4.2 – 4.6, must be incorporated into the SWMP document. The 

permittee’s construction program must ensure the following minimum requirements 

are effectively implemented for all construction activity discharging to its MS4: 

[Insert specific minimum requirements, such as:

a. Erosion and Sediment Controls. Design, install and maintain effective erosion 

controls and sediment controls to minimize the discharge of pollutants. At a 

minimum, such controls must be designed, installed and maintained to: 

(1) Control stormwater volume and velocity within the site to minimize soil 

erosion; 

(2) Control stormwater discharges, including both peak flowrates and total 

stormwater volume, to minimize erosion at outlets and to minimize 

downstream channel and streambank erosion; 

(3) Minimize the amount of soil exposed during construction activity; 

(4) Minimize the disturbance of steep slopes; 

(5) Minimize sediment discharges from the site. The design, installation and 

maintenance of erosion and sediment controls must address factors such as 

the amount, frequency, intensity and duration of precipitation, the nature of 

resulting stormwater runoff, and soil characteristics, including the range of 

soil particle sizes expected to be present on the site; 

(6) Provide and maintain natural buffers around surface waters, direct 

stormwater to vegetated areas to increase sediment removal and maximize 

stormwater infiltration, unless infeasible; and 

(7) Minimize soil compaction and, unless infeasible, preserve topsoil. 

b. Soil Stabilization. Stabilization of disturbed areas must, at a minimum, be 

initiated immediately whenever any clearing, grading, excavating or other earth 

disturbing activities have permanently ceased on any portion of the site, or 

temporarily ceased on any portion of the site and will not resume for a period 

exceeding 14 calendar days. Stabilization must be completed within a period of 

Chapter 4: Construction 38
MS4 Permit Improvement Guide 

time determined by the permittee. In arid, semiarid, and drought-stricken areas 

where initiating vegetative stabilization measures immediately is infeasible, 

alternative stabilization measures must be employed as specified by the 

permittee. 

c. Dewatering. Discharges from dewatering activities, including discharges from 

dewatering of trenches and excavations, are prohibited unless managed by 

appropriate controls. 

d. Pollution Prevention Measures. Design, install, implement, and maintain 

effective pollution prevention measures to minimize the discharge of pollutants. 

At a minimum, such measures must be designed, installed, implemented and 

maintained to: 

(1) Minimize the discharge of pollutants from equipment and vehicle washing, 

wheel wash water, and other wash waters. Wash waters must be treated in 

a sediment basin or alternative control that provides equivalent or better 

treatment prior to discharge; 

(2) Minimize the exposure of building materials, building products, construction 

wastes, trash, landscape materials, fertilizers, pesticides, herbicides, 

detergents, sanitary waste and other materials present on the site to 

precipitation and to stormwater; and 

(3) Minimize the discharge of pollutants from spills and leaks and implement 

chemical spill and leak prevention and response procedures. 

e. Prohibited Discharges. The following discharges are prohibited: 

(1) Wastewater from washout of concrete, unless managed by an appropriate 

control; 

(2) Wastewater from washout and cleanout of stucco, paint, from release oils, 

curing compounds and other construction materials; 

(3) Fuels, oils, or other pollutants used in vehicle and equipment operation and 

maintenance; and, 

(4) Soaps or solvents used in vehicle and equipment washing. 

f. Surface Outlets. When discharging from basins and impoundments, utilize 

outlet structures that withdraw water from the surface, unless infeasible. 

Example Permit Requirement Rationale for the Fact Sheet 

Stormwater discharges from construction sites generally includes sediment and other pollutants 

such as phosphorus and nitrogen, turbidity, pesticides, petroleum derivatives, construction 

chemicals, and solid wastes that may become mobilized when land surfaces are disturbed. The 

permit requires MS4 permittees to require construction site operators at defined sites to meet 

certain minimum stormwater requirements relating to erosion and sediment control and 

pollution prevention, and to meet other restrictions imposed on them by the State, or local 

regulations. These minimum requirements clearly specify the expectations for addressing 

Chapter 4: Construction 39
MS4 Permit Improvement Guide 

erosion control, sediment control, and pollution prevention control measures at construction 

sites. 

EPA’s Effluent Limitations Guidelines and Standards for the Construction and Development 

Point Source Category (74 FR 62996, December 1, 2009) require construction site owners and 

operators to implement a range of erosion and sediment control measures and pollution 

prevention practices to control pollutants in discharges from construction sites. These 

standards will be required in state construction general permits as they are reissued. These 

standards are broadly applicable to all construction activity disturbing one or more acres. They 

provide an objective means of describing appropriate erosion and sediment control best 

management practices, pollution prevention controls on construction site waste and storage of 

building materials and other reasonable components of the permittee’s program to reduce 

pollutants to the maximum extent practicable in stormwater from construction sites that 

discharge through the MS4. 

Recommendations for the Permit Writer 

The Phase II stormwater regulations require permittees to develop a construction site program 

addressing “land disturbance of greater than or equal to one acre.” However, some states may have 

more stringent requirements that apply to some permittees, or the permit writer may have 

discretion to lower the one acre threshold if this threshold is too high for particular permittees. For 

example, smaller, built-out cities may have many small redevelopment projects that fall below the 

one acre threshold. In such cases, controlling construction site stormwater entering the MS4 to the 

maximum extent practicable may require stormwater controls at smaller sites. Permit writers 

should review available construction and planning data from the MS4 to determine an appropriate 

project size threshold. 

The example permit provision’s list of minimum requirements for erosion controls, sediment 

controls, and pollution prevention measures is intended to establish specific requirements to 

implement the broader requirements in the Phase II rule (40 CFR 122.24(b)(4)). The list of minimum 

requirements in the example permit provision are from EPA’s Construction and Development 

Effluent Guidelines (published December 1, 2009) which will eventually be required in all NPDES 

stormwater permits issued to construction site operators. At a minimum, the permit should 

reference the applicable state standards and, where appropriate, any local standards as well. 

Permit writers may wish to modify these specific requirements based on current standards or 

guidance on construction site stormwater controls in the State. 

4.2 Construction Site Inventory 

Example Permit Provision 

4.2.1 The permittee must continue to maintain an inventory of all active public and 

private construction sites that result in a total land disturbance of [insert disturbance 

threshold from Part 4.1.1.]. The inventory must be continuously updated as new 

projects are permitted and projects are completed. The inventory must contain 

Chapter 4: Construction 40
MS4 Permit Improvement Guide 

relevant contact information for each project (e.g., name, address, phone, etc.), the 

size of the project and area of disturbance, whether the project has submitted for 

permit coverage under [insert name of applicable NPDES general construction 

permit], the date the permittee approved the [insert name of local erosion and 

sediment control/stormwater plan] in accordance with Part 4.3, and the permit 

tracking number issued by [insert name of permitting authority]. The permittee 

must make it available to the permitting authority upon request. 

Example Permit Requirement Rationale for the Fact Sheet 

To effectively conduct inspections, the permittee must know where construction activity is 

occurring. A construction site inventory tracks information such as project size, disturbed area, 

distance to any waterbody or flow channel, when the erosion and sediment control/stormwater 

plan was approved by the Permittee, and whether the project is covered by the permitting 

authority’s construction general permit. This inventory will allow the permittee to track and 

target its inspections. 

Recommendations for the Permit Writer 

Because of state or local construction permitting requirements, many permittees have some system 

in place to track construction activity in their jurisdiction. If this is the first MS4 permit issued to the 

permittee, the permit writer should include a deadline for the development of the initial inventory. 

Permit writers may want to request electronic copies of the inventory quarterly or yearly, if that 

information will be used by the State permitting or inspection staff. 

4.3 Construction Plan Review Procedures 

Example Permit Provision 

4.3.1 The permittee must continue to require each operator of a construction activity to 

prepare and submit a [insert name of local erosion and sediment control/stormwater 

plan] prior to the disturbance of land for the permittee’s review and written 

approval prior to issuance of a [insert appropriate permit, i.e. grading or 

construction]. The permittee must make it clear to operators of construction activity 

that they are prohibited from commencing construction activity until they receive 

receipt of written approval of the the plans. If the [insert name of local erosion and 

sediment control/stormwater plan] is revised, the permittee must review and 

approve those revisions. 

4.3.2 The permittee must continue to implement site plan review procedures that meet 

the following minimum requirements: 

a. The permittee must not approve any [insert name of local erosion and sediment 

Chapter 4: Construction 41
MS4 Permit Improvement Guide 

control/stormwater plan] unless it contains appropriate site-specific 

construction site control measures that meet the minimum requirements in Part 

4.1.1 of this permit. 

b. The stormwater pollution prevention plan (SWPPP) developed pursuant to 

[insert name of applicable NPDES general construction permit] may substitute 

for the [insert name of local erosion and sediment control/stormwater plan] for 

projects where a SWPPP is developed. The permittee is responsible for 

reviewing those portions of the SWPPP that comply with the [insert name of 

local erosion and sediment control/stormwater plan]. 

c. The [insert name of local erosion and sediment control/stormwater plan] must 

include the rationale used for selecting control measures, including how the 

control measure protects a waterway or stormwater conveyance. 

d. The permittee must use qualified individuals, knowledgeable in the technical 

review of [insert name of local erosion and sediment control/stormwater plan] to 

conduct such reviews. 

e. The permittee must document its review of each [insert name of local erosion 

and sediment control/stormwater plan] using a checklist or similar process. 8

Example Permit Requirement Rationale for the Fact Sheet 

The permit requires the review and prior approval of all local erosion and sediment control 

plans/stormwater plans to ensure that construction activities adhere to the permittee's 

minimum stormwater control requirements. Adequate review of erosion and sediment 

control/stormwater plans is necessary to verify compliance with all applicable requirements in 

the permittee’s ordinance or other regulatory mechanism, as well as compliance with control 

measure standards and specifications. A formalized review procedure ensures consistent 

review of plans by specifying the requirements for plans being submitted, the schedule for 

review, and general conditions for approval. The site plan review process also provides a way to 

track construction activities and enforce standards. 

A good site plan review process provides the permittee with the opportunity to comment – 

early and often – on a project’s proposed number, type, location, and sizing of stormwater 

control measures that will be in place prior to, during, and at the conclusion of active 

construction. It is important to keep in mind that a site plan is a “living document” that may 

change during the life of the project; however, it is critical that the site plan be adequately 

reviewed and initially based on established policy, guidelines, and standards. The plan is the 

framework for stormwater control implementation, as well as the basis of any enforcement 

action on a project site. 

The permit requires the permittee to review plans before construction activity begins to ensure 

that the plans are consistent with the standards specified in Part 4.1.1. The permit language also 

includes some key requirements during the plan review process: 

 

8

 2009 Ventura County, CA Phase I MS4 Permit 

(www.swrcb.ca.gov/rwqcb4/water_issues/programs/stormwater/municipal/ventura_ms4/09-0057/

Transmittal%20Letter%20and%20MS4%20Permit%20Order%20No%2009%200057.pdf) 

Chapter 4: Construction 42
MS4 Permit Improvement Guide 

 If a SWPPP is developed for the State construction general permit, that plan may substitute 

for the local plan if it also includes/addresses the local requirements. 

 The plan must include the rationale used for selecting or rejecting control measures (for 

example, why a silt fence was selected or why a sediment trap was not included). 

 Finally, plan reviewers must be trained and must document their review. For example, this 

can be done by using a checklist or similar process. 

Recommendations for the Permit Writer 

Some MS4 permits include a requirement that, prior to approval of local permits, the permittee 

must verify that the construction site operator has existing coverage under the State’s Construction 

General Permit, if necessary. This requirement helps to reduce the number of non-filers for the 

State general permit by providing a check for NPDES CGP permit coverage at the local level. 

4.4 Construction Site Inspections and Enforcement 

Example Permit Provision 

4.4.1 The permittee must continue to implement procedures for inspecting public and 

private construction projects in accordance with the frequency specified in Table 4-1 

below: 

Table 4-1: Inspection Frequencies 

Site Inspection Frequency 

a. All sites [insert a size threshold that is 

considered large for the MS4 if large projects 

are common, e.g. 5 acres] or larger in size 

b. All sites one (1) acre or larger that discharge 

to a tributary listed by the state/tribe as an 

impaired water for sediment or turbidity under 

the CWA section 303(d) 

c. Other sites one (1) acre or more determined 

by the permittee or permitting authority to be 

a significant threat to water quality* 

Inspection must occur within [insert 

number of days/hours, e.g. 48 hours] of a 

[insert significant rain event size, e.g. 1⁄2 

inch rain event] and no less than biweekly 

(every 2 weeks)] 

d. All other construction sites with one (1) acre 

or more of soil disturbance not meeting the 

criteria specified in (A),(B), or (C) above 

Inspection must occur at least monthly 

e. Construction sites less than one (1) acre in 

size 

Inspection must occur as needed based 

on the evaluation of the factors that are a 

threat to water quality* 

*In evaluating the threat to water quality, the following factors must be considered: soil 

erosion potential; site slope; project size and type; sensitivity of receiving waterbodies; 

proximity to receiving waterbodies; non-stormwater discharges; past record of non-compliance 

by the operators of the construction site; and [insert other factors relevant to particular MS4]. 

Chapter 4: Construction 43
MS4 Permit Improvement Guide 

4.4.2 The permittee must adequately inspect all phases of construction. 

a. Prior to Land Disturbance: Prior to allowing an operator to commence land 

disturbance, the permittee must perform an inspection to ensure all necessary 

erosion and sediment controls are in place. 

b. During Active Construction: During active construction, the permittee is required 

to conduct inspections in accordance with the frequencies specified in Table 4-1 

in Part 4.4.1. 

c. Following Active Construction: At the conclusion of the project, the Permittee must 

inspect all projects to ensure that all graded areas have reached final stabilization 

and that all temporary control measures are removed (e.g., silt fence). 

4.4.3 The permittee must have trained and qualified inspectors (See Part 4.5). The 

permittee must also continue to follow, and revise as necessary, written procedures 

outlining the inspection and enforcement procedures. Inspections of construction 

sites must, at a minimum: 

a. Check for coverage under the [insert name of applicable NPDES general 

construction permit] by requesting a copy of any application or Notice of Intent 

(NOI) or other relevant application form during initial inspections. 

b. Review the applicable [insert name of local erosion and sediment 

control/stormwater plan] and conduct a thorough site inspection to determine if 

control measures have been selected, installed, implemented, and maintained 

according to the plan. 

c. Assess compliance with the permittee’s ordinances and permits related to 

stormwater runoff, including the implementation and maintenance of 

designated minimum control measures. 

d. Assess the appropriateness of planned control measures and their effectiveness. 

e. Visually observe and record non-stormwater discharges, potential illicit 

connections, and potential discharge of pollutants in stormwater runoff. 

f. Provide education and outreach on stormwater pollution prevention, as needed. 

g. Provide a written or electronic inspection report generated from findings in the 

field 

4.4.4 The permittee must track the number of inspections for the inventoried construction 

sites throughout the reporting period to verify that the sites are inspected at the 

minimum frequencies required. Inspection findings must be documented and 

maintained for review by the permitting authority. 

4.4.5 Based on site inspection findings, the permittee must take all necessary follow-up 

actions (i.e., re-inspection, enforcement) to ensure compliance in accordance with 

the permittee’s enforcement response plan required in Part 1.3. These follow-up 

and enforcement actions must be tracked and maintained for review by the 

permitting authority. 9

 

9

 2007 San Diego Phase I MS4 Permit (www.swrcb.ca.gov/rwqcb9/water_issues/programs/stormwater/docs/

sd_permit/r9_2007_0001/2007_0001final.pdf) 

Chapter 4: Construction 44
MS4 Permit Improvement Guide 

Example Permit Requirement Rationale for the Fact Sheet 

The permit requires inspections of construction sites based on a prioritized ranking of sites (see 

40 CFR 122.26(d)(2)(iv)(D)(3) and 122.34(b)(4)(ii)(F)). Larger construction sites and sites that 

discharge to a sediment impaired waterbody are inspected more frequently than small sites. In 

addition to inspections at a regular interval, inspections are required within a certain timeframe 

after a rain event. 

Inspections are required before land disturbance to ensure erosion and sediment controls are in 

place and a plan has been developed, during active construction, and after the site has been 

stabilized. The permit language also contains specific requirements on what the inspection 

must include (such as a comparison of control measures in the approved plan to measures 

installed in the field). 

Without adequate implementation and maintenance, stormwater controls will not function as 

designed. In order to ensure proper implementation and maintenance by site operators, a 

rigorous inspection protocol is necessary. This protocol must include a written SOP for site 

inspections and enforcement to ensure inspections and enforcement actions are conducted in a 

consistent manner. The SOP must include steps to identify priority sites for inspection and 

enforcement based on the nature and extent of the construction activity, slope of the site, 

proximity to receiving waters, the characteristics of soils, and the water quality status of the 

receiving water. This will allow inspection resources and staff time to be used most effectively. 

Documentation of inspections is critical to track noncompliance and enforcement. Regularly 

scheduled inspections, as well as post-storm event inspections, are necessary to be sure that 

regular maintenance occurs as well as repairs after storm events. 

Recommendations for the Permit Writer 

Selecting an appropriate inspection frequency is, by necessity, a case-by-case exercise. Inspection 

frequencies for one permittee will not necessarily be appropriate for other permittees. For 

example, appropriate inspection frequencies may vary among different permittees depending on 

such factors as topography and rainfall patterns, including whether the MS4 is located in a wet or 

arid region and/or has distinct wet and dry seasons. Appropriate inspection frequencies may also 

vary seasonally or geographically within a single MS4 based on seasonal variations in rainfall or 

snowfall, or differing topographical or geographic conditions in different parts of the MS4 area. 

For individual MS4 permits, permit writers should consider seasonal rainfall patterns, the presence 

and location of impaired streams or sensitive habitats, soils, topography, and other MS4-specific 

factors. In addition, permit writers should review current inspection frequencies, as well as 

inspection and enforcement records. 

The permit writer should also note that the permit language will need to be modified if the 

permittee was not previously required to develop written procedures for the inspection and 

enforcement conducted at construction sites. 

Chapter 4: Construction 45
MS4 Permit Improvement Guide 

4.5 MS4 Staff Training 

Example Permit Provision 

4.5.1 The permittee must ensure that all staff whose primary job duties are related to 

implementing the construction stormwater program, including permitting, plan 

review, construction site inspections, and enforcement, are trained to conduct these 

activities. The training can be conducted by the permittee or outside training can be 

attended, however, this training must include, at a minimum: 

a. Erosion and Sediment Control/Stormwater Inspectors: 

1. Initial training, held within the first permit year, regarding proper control 

measure selection, installation, implementation, and maintenance, as well 

as administrative requirements such as inspection reporting/tracking and 

use of the permittee’s enforcement responses; and 

2. Annual refresher training for existing inspection staff to update them on 

preferred controls, regulation changes, permit updates, and policy or 

standards updates. Throughout the year, e-mails and/or memos must be 

sent out to update the inspectors as changes happen. 

b. Other Construction Inspectors: Initial training must be held within the first 

permit year, on general stormwater issues, basic control measure 

implementation information, and procedures for notifying the appropriate 

personnel of noncompliance. Refresher training held at least once every two 

years. 

c. Plan Reviewers: 

1. Initial training, held within the first permit year, regarding control measure 

selection, design standards, and review procedures; and 

2. Annual training regarding new control measures, innovative approaches, 

permit updates, regulation changes, and policy or standard updates. 

d. Third-Party Inspectors and Plan Reviewers: If the permittee utilizes outside 

parties to conduct inspections and/or review plans, these outside staff must be 

trained per the requirements listed in Part 4.5.1.a (above). 

Example Permit Requirement Rationale for the Fact Sheet 

By setting up training for the permittee staff, the permittee can ensure that the erosion and 

sediment control requirements are understood and consistently applied since all staff will have 

been trained on the same information. The permit requires staff whose primary job duties are 

related to implementing the construction stormwater program to be trained. The training 

requirements vary by the type of staff. F or example, erosion and sediment control inspectors 

must be trained annually on a range of topics, while other construction inspectors (such as 

building inspectors) will receive more general training. 

Chapter 4: Construction 46
MS4 Permit Improvement Guide 

The permittee can conduct the training or the training can be provided by another entity (such 

as a State erosion and sediment control class). Ideally, the training should include classroom 

presentations, in-field training, and follow-up evaluations to determine whether the training 

was effective. 

Also, the permittee should consider providing training to other in-field municipal staff so that 

problems associated with flooding and sedimentation from construction sites can be properly 

reported and addressed. 

4.6 Construction Site Operator Education & Public Involvement 

Example Permit Provision 

4.6.1 Construction Operator Education. The permittee must develop and distribute 

educational materials to construction site operators as follows: 

a. Each year, the permittee must either provide information on existing training 

opportunities or develop new training for construction operators on control 

measure selection, installation, implementation, and maintenance as well as 

overall program compliance. 

b. The permittee must develop or utilize existing outreach tools (i.e. brochures, 

posters, website, plan notes, manuals etc.) aimed at educating construction 

operators on appropriate selection, installation, implementation, and 

maintenance of stormwater controls, as well as overall program compliance. 

c. The permittee must make available appropriate outreach materials to all 

construction operators who will be disturbing land within the MS4 boundary. 

The permittees’ contact information and website must be included in these 

materials. 

d. The permittee must include information on appropriate selection, installation, 

implementation, and maintenance of controls, as well as overall program 

compliance, on the permittee’s existing website. 

4.6.2 Public Involvement. 

a. The permittee must adopt and implement procedures for receipt and 

consideration of information submitted by the public regarding construction 

projects. This includes, but is not limited to, the public reporting mechanisms 

described in Part 3.6. 

b. The permittee must hold public meetings for all public projects that have 

planned disturbance greater than or equal to an acre. 10

 

10 Eastern Washington MS4 Phase II Permit (Part 2 only) (www.ecy.wa.gov/programs/wq/stormwater/municipal/

phaseiiEwa/MODIFIEDpermitDOCS/EWpermitMODsigned.pdf) 

Chapter 4: Construction 47
MS4 Permit Improvement Guide 

Chapter 4: Construction 48

Example Permit Requirement Rationale for the Fact Sheet 

Education of construction site operators regarding stormwater management and regulatory 

requirements is an essential part of controlling stormwater discharges from construction sites. 

Making brochures, guidance documents and trainings available will increase the knowledge of 

operators and compliance in the field and can help them choose the correct structural control 

and processes, correctly install the controls, and successfully implement control measures. The 

permit requires the permittee to provide appropriate outreach materials to construction site 

operators. These materials can be made available during the normal course of business (i.e. in 

BMP manuals, in plan notes, during meetings) or via brochures or websites. In addition, the 

permittee must either provide training or notify the operators of available training 

opportunities. 

Public involvement requirements include the development of a hotline or other telephone 

number for the public to call regarding stormwater concerns at construction sites. 
CHAPTER 5: POST-CONSTRUCTION OR PERMANENT/LONG-TERM 

STORMWATER CONTROL MEASURES

Introduction 

Phase I MS4s are required to address new development and 

significant redevelopment in their SWMPs through controls to 

reduce pollutants in stormwater discharges after construction is 

completed. See 40 CFR 122.26(d)(2)(iv)(A)(2). 

Included Concepts

► Post-construction 

stormwater management 

program 

► Site performance 

standards 

► Site plan review 

► Long-term maintenance 

of post-construction 

stormwater control 

measures 

► Watershed protection 

► Tracking of postconstruction stormwater 

control measures 

► Inspections and 

enforcement 

► Retrofit plan 

The Phase II regulations require regulated small MS4 operators to 

develop, implement, and enforce a program to address stormwater 

discharges from new development and redevelopment sites that 

disturb greater than or equal to one acre to the MS4 (including 

projects that disturb less than one acre that are part of a larger 

common plan of development or sale). The regulations also require 

that the MS4 ensure that control measures are installed and 

implemented that prevent or minimize water quality impacts. See 

40 CFR 122.34(b)(5)(i) 

As part of these Phase II requirements, the MS4 must: 

 Develop and implement approaches to addressing postconstruction stormwater discharges that include a 

combination of structural and/or non-structural 

controls; 

 Adopt adequate legal authority to enable the MS4 to 

address post-construction stormwater discharges from 

new development and redeveloped sites; and 

 Ensure adequate long-term operation and maintenance of applicable post-construction 

control measures. See 40 CFR 122.34(b)(5)(ii). 

As of April 2010, most MS4 permits only require permittees to adopt a post-construction program with 

enforceable requirements designed to reduce stormwater impacts from new development and 

redevelopment, without specifying a performance standard. To meet this requirement many MS4s have 

adopted criteria in ordinances or other legally enforceable mechanisms based on already promulgated 

flood-control based standards (i.e., focused only on discharge rates). However, performance standards 

can be a very useful and meaningful mechanism in the post-construction toolbox to ensure that water 

quality objectives are met. 

The example permit provisions that follow present the current thinking on how to strengthen the 

effectiveness of the permittee’s stormwater program by preventing the harmful effects of increased 

stormwater flows and pollutant loads from new development and redeveloped sites on receiving 

waterbodies. EPA recognizes that there are a wide variety of approaches that some states have already 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 49 
MS4 Permit Improvement Guide 

taken to control discharges from new development and redeveloped sites, some of which are more 

stringent than the permit language recommended below. The language below includes components 

that EPA believes would provide focus and enforceability, and would bring about significant 

improvements in stormwater controls on site. However, the “maximum extent practicable” may be 

greater than is reflected in the example permit language below for some MS4s, and EPA encourages 

states, where possible, to go beyond these example provisions and to achieve even better watershed 

planning and water quality outcomes. For these reasons, this chapter presents the minimum permit 

provisions EPA currently recommends to be included in permits in order for permittees to reduce their 

discharges to the maximum extent practicable as well as the optional, more stringent, requirements. 

5.1 Post-Construction Stormwater Management Program 

Example Permit Provision 

5.1.1 The permittee must continue to implement a program to control stormwater 

discharges from new development and redeveloped sites that disturb at least one 

acre (including projects that disturb less than one acre that are part of a larger 

common plan of development or sale) that discharge into an MS4 [or insert smaller 

alternative size]. The program must apply to private and public development sites, 

including roads. 

5.1.2 The program must require that controls are in place that will infiltrate, 

evapotranspire, or harvest and use stormwater from the site to meet the 

performance standards in Part 5.2 to protect water quality. 

5.1.3 Written procedures for implementing this program, including the components 

described in Parts 5.2 – 5.8, must be incorporated into the SWMP document. 

Example Permit Requirement Rationale for the Fact Sheet 

The stormwater regulations require that an MS4 develop and implement a program to address 

post-construction discharges from new development and redeveloped sites, and ensure the 

long-term operation and maintenance of these controls (see Part 5.4 for the maintenance 

requirements). (See 40 CFR 122.34(b)(5)). The permit requires the use of specific stormwater 

controls, i.e., those that infiltrate, evapotranspire, or harvest and use stormwater, with the aim 

of maintaining or restoring the pre-development stormwater runoff conditions at the site. 

Many traditional stormwater management practices, and the permit language that drives them, 

fail to address the hydrologic modifications that increase the quantity of stormwater discharges, 

and cause excessive erosion and stream channel degradation. Frequently the volume, duration, 

and velocity of stormwater discharges cause degradation to aquatic systems. Protecting and 

restoring the physical, chemical and biological integrity of receiving waters must be a central issue 

in stormwater permits. The recent report of the National Research Council (Urban Stormwater 

Management in the United States, National Academies Press, 2008, 

www.epa.gov/npdes/pubs/nrc_stormwaterreport.pdf) recommends that the NPDES stormwater 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 50
MS4 Permit Improvement Guide 

program examine the impacts of stormwater flow, treat flow as a surrogate for other pollutants, 

and includes the necessary control requirements in stormwater permits. Specifically the report 

recommends that the volume retention practices of infiltration, evapotranspiration and rainwater 

harvesting be used as primary stormwater management mechanisms. For this reason, EPA 

recommends use of a permit condition that is based on maintaining or restoring predevelopment 

hydrology although other forms of this permit condition maybe appropriate as well. 

Additional information on the development of a post-construction program for Phase II 

permittees can be found in the Center for Watershed Protection’s Managing Stormwater In 

Your Community: A Guide for Building an Effective Post-Construction Program (available at 

www.cwp.org/postconstruction). Also, EPA’s green infrastructure website includes information 

on post-construction controls and programs (see www.epa.gov/greeninfrastructure). 

5.2 Site Performance Standards 

Example Permit Provision 

5.2.1 The permittee must establish, implement and enforce a requirement that owners or 

operators of new development and redeveloped sites discharging to the MS4, which 

disturb greater than or equal to one acre (including projects that disturb less than 

one acre that are part of a larger common plan of development or sale), design, 

install, implement, and maintain stormwater control measures that infiltrate, 

evapotranspire, harvest, and use stormwater discharges. 

5.2.2 Within [insert deadline, e.g., 12 months, 24 months, etc.] the permittee must require 

that stormwater discharges from such new development and redevelopment sites 

be managed such that post-development hydrology does not exceed the predevelopment hydrology at the site, in accordance with the performance standard set 

forth in this paragraph. The SWMP must describe the site design strategies, control 

measures, and other practices deemed necessary by the permittee to maintain or 

improve pre-development hydrology.11 [Insert a new development performance 

standard, such as one or a combination of the following:

Basis for Performance 

Standard Description Performance Standard 

Rainfall Minimum storm 

volume to be retained 

on site. 

Design, construct, and maintain stormwater management 

practices that manage rainfall on-site, and prevent the offsite discharge of the precipitation from [insert standards, 

such as “the first one inch of rainfall from a 24-hour storm 

preceded by 48 hours of no measurable precipitation”]. 

Discharge volume reduction can be achieved by canopy 

interception, soil amendments, evaporation, rainfall 

harvesting, engineered infiltration, extended filtration 

and/or evapotranspiration and any combination of the 

aforementioned practices. This first one inch of rainfall 

 

11 Big Darby Creek Watershed CGP, Part III.G.2.d. 

(web.epa.ohio.gov/dsw/permits/DarbyStormWater_Final_GP_sep06.pdf) 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 51
MS4 Permit Improvement Guide 

must be 100% managed with no discharge to surface 

waters, except when the permittee chooses to implement 

the conditions in Part 5.2.5.d below.12

Rainfall Minimum storm size 

to be retained on site. 

Design, construct, and maintain stormwater management 

practices that manage rainfall on-site, and prevent the 

off-site discharge of the precipitation from all rainfall 

events less than or equal to [insert standards, such as “the 

95th percentile rainfall event”]. This objective must be 

accomplished by the use of practices that infiltrate, 

evapotranspire and/or harvest and reuse rainwater. The 

95th percentile rainfall event is the event whose 

precipitation total is greater than or equal to 95 percent 

of all storm events over a given period of record.13

Recharge/Runoff Hydrologic analysis. Design, construct, and maintain stormwater management 

practices that preserve the pre-development runoff 

conditions following construction. The post-construction 

rate, volume, duration and temperature of discharges 

must not exceed the pre-development rates and the predevelopment hydrograph for 1, 2, 10, 25, 50 and 100 year 

storms must be replicated through site design and other 

appropriate practices. These goals must be accomplished 

through the use of infiltration, evapotranspiration, and/or 

rainwater harvesting and reuse practices. Defensible and 

consistent hydrological assessments and modeling 

methods must be used and documented. 14

Recharge Groundwater 

recharge 

requirement. 

Any “major development” project, which is one that 

disturbs [insert standards, such as at least one (1) acre of 

land or creates at least 0.25 acres of new or additional 

impervious surface], must comply with one of the 

following two groundwater recharge requirements: 

 Demonstrate through hydrologic and hydraulic 

analysis that the site and its stormwater 

management measures maintain 100 percent of the 

average annual pre-construction groundwater 

recharge volume for the site; or 

 Demonstrate through hydrologic and hydraulic 

analysis that the increase of stormwater discharges 

volume from pre-construction to post-construction 

for the two-year storm is infiltrated.15

Impervious Cover Limiting total 

impermeable surface 

(or effective 

impermeable surface)

Minimize total impervious cover resulting from new 

development and redevelopment to [insert standards, 

such as <10% of disturbed land cover and/or limit total 

amount of effective impervious surface to no more than 

5% of the landscape]. 

 

12 West Virginia Small MS4 Permit (www.wvdep.org/Docs/17444_SW_WV%20MS4%20permit%202009.pdf) 13 Section 438, Energy Independence & Security Act (EISA) Guidance 

(www.epa.gov/owow/NPS/lid/section438/pdf/final_sec438_eisa.pdf) 14 Section 438, Energy Independence & Security Act (EISA) Guidance 

(www.epa.gov/owow/NPS/lid/section438/pdf/final_sec438_eisa.pdf) 15 New Jersey Stormwater Management Rules, N.J.A.C. 7:8 

(www.nj.gov/dep/rules/adoptions/2004_0202_njpdes.pdf)

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 52
MS4 Permit Improvement Guide 

5.2.3 Incentives for Redeveloped Sites. When considered at the watershed scale, certain 

types of developed sites can either reduce existing impervious surfaces, or at least 

create less ‘accessory’ impervious surfaces. The Permittee may develop a program 

to allow adjustments to the performance standard for new development or 

redevelopment sites that qualify. A reduction of [insert the amount of stormwater 

the Permittee can reduce for utilizing redevelopment principles, e.g. 0.2 inches from 

the one inch runoff reduction standard] may be applied to any of the following types 

of development. Reductions are additive up to a maximum reduction of [insert 

amount, such as 0.75 inches] for a project that meets four or more criteria. The 

permittee may choose to be more restrictive and allow a reduction of less than 

[insert amount, such as 0.75 inches] if they choose. In no case will the reduction be 

greater than [insert amount, such as 0.75 inches]. 

1. Redeveloped sites 

2. Brownfield redeveloped site 

3. High density (>7 units per acre) 

4. Vertical Density, (Floor to Area Ratio (FAR) of 2 or >18 units per acre) 

5. Mixed use and Transit Oriented Development (within 1⁄2 mile of transit)16

5.2.4 Additional Requirements and Exceptions: The permittee must implement the 

following additional requirements where applicable: 

a. A site that is a potential hot spot with the reasonable potential for 

contaminating underground sources of drinking water must provide treatment 

for associated pollutants (e.g., petroleum hydrocarbons at a vehicle fueling 

facility). 

b. A site that discharges or proposes to discharge to any surface water or ground 

water that is used as a source of drinking water must comply with all applicable 

requirements relating to source water protection and must not cause an 

exceedance of drinking water standards.17

c. Sites may not infiltrate stormwater in areas of soil contamination. 

d. For projects that cannot meet 100% of the performance standard in Part 5.2.2 

on site, two alternatives are available: off-site mitigation and payment in lieu. If 

these alternatives are chosen, then the permittee must develop and fairly apply 

criteria for determining the circumstances under which these alternatives will be 

available and establish reasonable schedules for mitigation and require payment 

in lieu of prior to project inception. A determination that standards cannot be 

met on site must include multiple criteria that would rule out fully meeting the 

performance standard in Part 5.2.2, such as: too small a lot outside of the 

building footprint to create the necessary infiltrative capacity even with 

amended soils; soil instability as documented by a thorough geotechnical 

 

16 West Virginia Small MS4 Permit (Section C.b.5.a.ii.A.3) 

(www.wvdep.org/Docs/17444_SW_WV%20MS4%20permit%202009.pdf) 17 West Virginia Small MS4 Permit (Section C.b.5.a.ii.A.2) 

(www.wvdep.org/Docs/17444_SW_WV%20MS4%20permit%202009.pdf) 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 53
MS4 Permit Improvement Guide 

analysis; a site use that is inconsistent with capture and reuse of stormwater; or 

too much shade or other physical conditions that preclude adequate use of 

plants. Sites must still maximize stormwater retention on-site, before applying 

the remaining stormwater to one of the alternatives. In instances where 

alternatives are chosen, technical justification as to the infeasibility of on site 

management is required to be documented.18

Example Permit Requirement Rationale for the Fact Sheet 

Developed land changes the hydrology of sites, leading to higher stormwater discharge volumes 

and higher pollutant loads. The purpose of this standard is to maintain or restore stable 

hydrology in receiving waters thereby protecting water quality by having post-construction 

hydrology mimic the natural hydrology of the area. 

A simpler, but reasonably approximate ‘mimicking the natural hydrograph’ approach can 

typically be accomplished by retaining (as opposed to detaining stormwater for later discharge) 

on a developed site the volume of water that was retained prior to development, through the 

mechanisms of infiltration, evapotranspiration, and capture and use. By significantly reducing 

the volume of stormwater discharges, these mechanisms significantly reduce the discharge of 

pollutants in stormwater, making discharge volumes the ideal all-around focus and metric for 

stormwater management. These provisions must be clear about the retention requirement, 

e.g., an underdrained rain garden likely functions more as a detention and filtration system than 

an infiltration system. 

In Part 5.2.3, the five types of development which qualify for incentives are redevelopment, 

brownfield redevelopment, high density, vertical density, and mixed use with transit oriented 

development. Redeveloping already degraded sites can reduce regional land consumption and 

minimize new land disturbance. Minimizing land disturbance and impervious cover is critical to 

maintaining watershed health. In addition to water quality benefits, cleaning up and reinvesting 

in brownfield properties increases local tax bases, facilitates job growth, utilizes existing 

infrastructure, takes development pressures off of undeveloped, open land, and both improves 

and protects the environment. The effect of low-density urbanization on watersheds and the 

hydrologic cycle is substantial. High-density development, including vertical density, slows land 

consumption rates and accommodates more land uses on a smaller footprint. Finally, mixing 

land uses and promoting transit-oriented development can directly reduce runoff since mixeduse developments have the potential to use surface parking lots and transportation 

infrastructure more efficiently, requiring less pavement.19

In Part 5.2.4.d, the permittee must establish clear and stringent criteria for the conditions under 

which payment in lieu and off-site mitigation could be used. These criteria must be related to 

physical constraints such as a combination of soils which limit infiltration opportunities, space or 

light limited situations restricting the amount of vegetation that can be used, and a land use 

that is not conducive to capture and use of stormwater. Further, appropriate schedules for 

 

18 West Virginia Small MS4 Permit (Section C.b.5.a.ii.A.4) 

(www.wvdep.org/Docs/17444_SW_WV%20MS4%20permit%202009.pdf) 19 Adapted from the WV Phase II MS4 Fact Sheet 

(www.dep.wv.gov/WWE/Programs/stormwater/MS4/permits/Pages/default.aspx) 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 54
MS4 Permit Improvement Guide 

payment and implementation of mitigation measures must be established to ensure stormwater 

impacts are addressed in a timely manner. 

Recommendations for Permit Writer 

Many communities have adopted criteria based on already promulgated flood-control based 

standards (i.e., focused only on discharge rates). This example permit language instead promotes 

the concept that effective standards should be based on the objective of maintaining or restoring 

stable hydrology to protect the quality of receiving waters by having post-construction hydrology 

mimic the natural hydrology of the area. The permit language provides a number of example 

standards that can be used to achieve this objective. 

Performance standards should take into account the wide variability in hydrologic conditions in 

different areas. Ideally, standards should reflect the local naturally-occurring hydrology with respect 

to runoff, infiltration, evapotranspiration, and storage – that is, the water balance that would be 

present in the absence of development. Key parameters, such as rainfall patterns, soil 

characteristics, and topography, can be used to establish likely ‘natural’ hydrology. Where 

maintaining or reestablishing such hydrologic conditions is infeasible, off-site mitigation, paymentin-lieu, or fee programs may be used. Based on current (2010) information, EPA recommends that 

permits allow for a combination of techniques that utilize infiltration, capture and use, and 

evapotranspiration as appropriate, rather than relying only on infiltration or some other technique 

alone to meet performance standards. 

The permit writer could include a performance standard that stipulates that predevelopment 

hydrographs match post-development hydrographs. In order for this type of performance standard 

to be effective, the permit writer should make sure that the permit clearly spells out all variables of 

the hydrograph (volume, rate, duration, frequency) to be matched, and not just the discharge rate. 

Many current pre-post hydrology standards focus only on discharge rate, which is primarily a flood 

control approach. In addition, a pre-development condition should also be defined, and that 

condition should be one that is reasonably ‘natural’, rather than simply the conditions (perhaps 

already fairly impervious) that existed immediately prior to the current developed site. A calculator 

tool based on key hydrologic parameters (soil, rainfall, slope, and vegetation) or an on-site rainfall 

retention standard that is appropriate for that area can help the permittee determine what 

constitutes pre-development hydrology and the means by which it may be matched. 

As contemplated in the example permit provisions, permit writers may want to consider the difference 

between new development and redevelopment sites, as well as differences among some types of 

developed sites, in establishing performance standards. From the standpoint of imperviousness at a 

watershed scale, redeveloped sites are usually more desirable than new development sites, which 

replace relatively naturally functioning green spaces with impervious surfaces such as roads, and 

parking lots. Certain types of development generate less impervious surfaces than others. For 

example, typically, there is little or no increase in net stormwater discharges when redeveloping 

underused properties such as vacant properties, brownfield sites, or greyfield sites, since new 

impervious cover replaces existing impervious cover. The net discharge increase from already 

developed properties would likely be zero since the site was already predominately impervious cover. 

In many cases, redeveloped sites break up or remove some portion of the impervious cover, 

converting it to pervious cover and allowing for some stormwater infiltration. Redevelopment sites can 

produce a net improvement in regional water quality by decreasing total impervious area and its 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 55
MS4 Permit Improvement Guide 

associated stormwater discharges. Redeveloped sites can also reduce regional land consumption. By 

building on underused, already degraded land, the pressure to convert previously undeveloped land is 

reduced. Therefore differential standards for new development and redeveloped sites, as well as for 

different types of developed sites, may be reasonable. However, they should be crafted to minimize 

creation of imperviousness at the watershed scale, and still include some reasonable level of 

stormwater management at the site scale. 

Redevelopment is the act of improving by renewing or restoring any developed property that results 

in the land disturbance of one acre or greater, and that has one of the following characteristics: 

 Land that currently has an existing structure, such as buildings or houses, or 

 Land that is currently covered with an impervious surface, such as a parking lot or roof, or 

 Land that is currently degraded and is covered with sand, gravel, stones, or other non-vegetative 

covering. 

Infiltration may not be appropriate in all cases. For example, a site that is a potential hot spot with 

the reasonable potential for significant pollutant loading(s) may not be appropriate for stormwater 

infiltration. Hot spots may include commercial, industrial, institutional, municipal, or transportation 

related operations that may produce higher levels of stormwater pollutants, and/or present a higher 

level or risk for spills, leaks, or illicit discharges such as: gas stations, petroleum wholesalers, vehicle 

maintenance and repair, auto recyclers, recycling centers and scrap yards, landfills, solid waste 

facilities, wastewater treatment plants, airports, railroad stations and associated maintenance 

facilities, and highway maintenance facilities. 

In addition, the permit writer may want to consider what type of flexibility to afford sites where the 

owner/operator is not able to meet the performance standard on site. For instance, if a site is 

constrained by size or previous impervious surfaces, such that the use of control measures that 

infiltrate stormwater is severely limited, the permit could allow alternatives for meeting the 

performance standard in other ways such as payment in lieu and off-site mitigation within the same 

watershed. 

Off-site mitigation and payment in lieu programs are options that can be used in these instances. 

Off-site mitigation generally means that control measures may be implemented at another location, 

in the same sewershed/watershed as the original project, and as approved by the regulatory agency. 

Payment in lieu programs generally mean that the developer pays a fee to the permittee which will 

then be applied to a stormwater control project, in lieu of installing the required control measures. 

If the permit writer chooses to include an off-site mitigation or payment in lieu program in the 

permit, the permit writer could specify that the programs meet several criteria, for example, those 

described in the 2009 West Virginia Phase II General Permit Fact Sheet 

(www.dep.wv.gov/WWE/Programs/stormwater/MS4/permits/Pages/default.aspx): 

1. The permittee must establish clear and stringent criteria for the conditions under which these 

options are available that must be related to real physical constraints such as a combination of 

soils limiting infiltration opportunities, space or light limited situations restricting the amount of 

vegetation that can be used, and a land use that is not conducive to capture and use of 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 56
MS4 Permit Improvement Guide 

stormwater. While one or two of these characteristics should not be adequate to qualify for the 

alternative, the combination of multiple constraints could; 

2. A minimal requirement for at least [0.4 inch] of stormwater managed on-site; 

3. A [1:1.5 ratio] of the amount of requisite stormwater not managed on site to the amount of 

stormwater required to be mitigated at another site, or for which in-lieu payments must be made; 

4. If demonstrated to the permittee that it is completely infeasible to manage the remainder [0.4 

inches], then the ratio for this unmanaged portion is [1:2]. 

5. The necessary tracking systems for both types of programs, including the necessary inventory of 

public and retrofit projects for off-site mitigation; and, 

6. The establishment of a credible valuation structure for payment in lieu, i.e., what is the actual 

cost for the permittee to provide retrofits for the necessary amount of stormwater, not just a 

token payment. The purpose of these provisions is to disincentivize the use of alternatives unless 

really needed, but also to provide a financial foundation for implementation of public stormwater 

management projects, including retrofits where those needs have been identified. 

Additional justification for the development types which qualify for these incentives can be seen in 

the West Virginia Phase II MS4 Permit Fact Sheet 

(www.dep.wv.gov/WWE/Programs/stormwater/MS4/permits/Pages/default.aspx). 

5.3 Site Plan Review 

Example Permit Provision 

5.3.1 To ensure that all applicable new development and redeveloped sites conform to 

the performance standards required in Part 5.2, the permittee must continue to 

implement project review, approval, and enforcement procedures that include: 

a. Procedures for the site plan review and approval process(es) that include interdepartmental consultations, as needed, and a required re-approval process 

when changes to an approved plan are desired; and 

b. A requirement for submittal of ‘as-built’ certifications within 90 days of 

completion of a project. 

5.3.2 The permittee must conduct site plan reviews, using the procedures described in 

Part 5.3.1, of all new development and redeveloped sites which will disturb greater 

than or equal to one acre [or a smaller threshold as set by the permitting authority] 

and discharge to the MS4 (including sites that disturb less than one acre that are 

part of a larger common plan of development or sale). The site plan review must 

specifically address how the project applicant meets the performance standards in 

Part 5.2 and how the project will ensure long-term maintenance as required in 

Part 5.4. 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 57
MS4 Permit Improvement Guide 

Example Permit Requirement Rationale for the Fact Sheet 

Specific standards are a critical component of a stormwater management program. However, 

even the best requirements need to be supported by a review program to ensure that the 

standards are met. The example permit provision would require permittees to fully implement a 

comprehensive site plan review and approval program. To meet this requirement, the permittee 

must have the authority to withhold approvals when standards are not met. 

Recommendations for the Permit Writer 

The permit writer may want to consider adding a requirement for a pre-application concept plan 

meeting to occur (in addition to the requirement for the project applicant to submit a site plan for 

review). During this meeting the project land owner or developer, the project design engineer, and 

municipal planning staff could discuss the conceptual designs that would be used to ensure that 

they meet the performance standards. This meeting would ensure that stormwater and 

performance standards are addressed early in the development process. However, if this preapplication concept plan meeting is not consistent with local planning procedures, the permit writer 

could consider omitting this requirement. 

5.4 Long-Term Maintenance of Post-Construction Stormwater 

Control Measures 

Example Permit Provision 

5.4.1 All structural stormwater control measures installed and implemented to meet the 

performance standards of Part 5.2 must be maintained in perpetuity. The permittee 

must ensure the long-term maintenance of structural stormwater control measures 

installed according to this Part through one, or both, of the following approaches: 

a. Maintenance performed by the Permittee. See part 6.4. 

b. Maintenance performed by the owner or operator of a new development or 

redeveloped site under a maintenance agreement. The permittee must require 

the owner or operator of any new development or redeveloped site subject to 

the performance standards in Part 5.2 to develop and implement a maintenance 

agreement addressing maintenance requirements for any structural control 

measures installed on site to meet the performance standards. The agreement 

must allow the permittee, or its designee, to conduct inspections of the 

structural stormwater control measures and also account for transfer of 

responsibility in leases and/or deeds. The agreement must also allow the 

permittee, or its designee, to perform necessary maintenance or corrective 

actions neglected by the property owner/operator, and bill or recoup costs from 

the property owner/operator when the owner/operator has not performed the 

necessary maintenance within thirty (30) days of notification by the permittee or 

its designee. 

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5.4.2 Verification of maintenance responsibilities. The permittee must require that 

property owners or operators of any new development or redeveloped site subject 

to the performance standards in Part 5.2 provide verification of maintenance for the 

approved structural stormwater control measures used to comply with the 

performance standards. Verification must include one or more of the following as 

applicable: 

a. The owner/operator's signed statement accepting responsibility for 

maintenance with a provision for transferring maintenance responsibility if the 

property is legally transferred to another party; and/or 

b. Written conditions in the sales or lease agreement that require the recipient to 

assume responsibility for maintenance; and/or 

c. Written conditions in project conditions, covenants and restrictions for 

residential properties assigning maintenance responsibilities to a home owner’s 

association, or other appropriate group, for maintenance of structural and 

treatment control stormwater management practices; and/or 

d. Any other legally enforceable agreement that assigns permanent responsibility 

for maintenance of structural or treatment control stormwater management 

practices.

Example Permit Requirement Rationale for the Fact Sheet 

Appropriate operation and maintenance are critical aspects to the function of any suite of 

controls. In many cases, controls may be located on private property, and it is necessary to 

establish some provision to assure responsibility and accountability for the operation and 

maintenance of these controls. 

The permittee must ensure maintenance of all structural stormwater control measures. In this 

Guide, structural controls also include many green infrastructure practices such as rainwater 

harvesting, rain gardens, permeable pavement, and vegetated swales. 

Recommendations for the Permit Writer 

Most non-traditional MS4 permittees will probably not have the legal authority to recoup costs 

where the owner/operator has not completed necessary maintenance. Permit writers may want to 

be more specific in this requirement to include other options for non-traditional MS4 permittees. 

5.5 Watershed Protection 

Example Permit Provision 

5.5.1 When the Permittee revises its General Plan (or equivalent) or other relevant plans 

(e.g. Transportation Master, or Community Plan) they must include effective water 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 59
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quality and watershed protection elements that require implementation of 

consistent water quality protection measures for new development and 

redeveloped sites within [insert deadline]. Examples of water quality and watershed 

protection elements to be considered include the following: [insert principles and/or 

policies which are appropriate for the watershed such as,

 Minimize the amount of impervious surfaces (roads, parking lots, roofs, etc.) 

within each watershed, by minimizing the creation, extension and widening of 

parking lots, roads and associated development. 

 Preserve, protect, create and restore ecologically sensitive areas that provide 

water quality benefits and serve critical watershed functions. These areas may 

include, but are not limited to; riparian corridors, headwaters, floodplains and 

wetlands. 

 Implement management practices that prevent or reduce thermal impacts to 

streams, including requiring vegetated buffers along waterways, and 

disconnecting discharges to surface waters from impervious surfaces such as 

parking lots. 

 Prevent disturbances of natural waterbodies and natural drainage systems 

caused by development, including roads, highways, and bridges. 

 Avoid development in areas that are particularly susceptible to erosion and 

sediment loss. 

 Implement standards to protect trees, and other vegetation with important 

evapotranspirative qualities. 

 Implement policies to protect native soils, prevent topsoil stripping, and prevent 

compaction of soils. 

 Implement water conservation policies that will reduce both stormwater and 

non- stormwater discharges via storm sewer systems.20

 Implement policies that encourage stormwater practices close to the source of 

the runoff rather than downstream and lower in the watershed.] 

Example Permit Requirement Rationale for the Fact Sheet 

Imperviousness has been shown to correlate with water quality impacts. In order to minimize 

water quality impacts, the permittee must examine their planning principles to manage the 

creation of impervious surfaces at the watershed level, such as reducing the footprint of streets 

and parking lots. Also, ecologically sensitive areas can protect water quality by acting both as 

filters that reduce pollutants in stormwater discharges and as sponges to reduce the impact on 

the ecosystem’s hydrology. Thermal pollution is also a concern that can impact biota in 

waterways. Stormwater discharges from impervious surfaces are often characterized by higher 

temperatures than natural, pervious surfaces. Reducing the chances of further increasing this 

temperature by preserving, protecting, and restoring natural features that provide shading for 

the waterway can further help reduce thermal pollution. Whenever possible natural waterways 

 

20 West Virginia Small MS4 Permit (www.wvdep.org/Docs/17444_SW_WV%20MS4%20permit%202009.pdf) 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 60
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must be protected and not disturbed by stormwater from developed sites. For example, areas 

that have a high potential for erosion must be avoided for development when possible. 

Protecting vegetation, native soils, and conserving water can also help ensure the hydrologic 

qualities of the site remain intact. 

Consideration of stormwater impacts from development is critical during the planning phases of 

development. This not only includes planning on the site-level, but also with respect to 

discharges from the MS4 on the watershed level. To the extent possible, stormwater 

management must be an integral part of higher level planning documents that determine where 

and how development that will result in stormwater discharges to the MS4 should occur since 

these decisions affect water quality. Using land efficiently can result in better stormwater 

management by putting development where it is most appropriate. For example, by directing 

and concentrating new development in areas targeted for growth, communities can reduce or 

remove development pressure on undeveloped parcels and protect sensitive natural lands and 

recharge areas. Another strategy is redeveloping already degraded sites such as abandoned 

shopping centers or underutilized parking lots. In this case, the net increase in discharges from 

developed sites would likely be zero, and it would likely decrease, depending on the on-site 

infiltration practices used. Also, by allowing or encouraging denser development, less land is 

converted overall, and less total impervious area created. 

Recommendations for the Permit Writer 

Examining stormwater on a watershed basis and including watershed principles is an important part 

of protecting waterways in a holistic manner. Climate change may increase the size and frequency 

of storms in some area of the nation. Including watershed-type assessments and considerations as 

Permit Requirements will help the permittee better focus their efforts to ensure the best water 

protection outcomes for existing conditions and those anticipated future conditions. Therefore, 

permit writers should consider including watershed protection principles. Newer programs may not 

be ready for permit writers to include the exact example permit provision provided. If possible, 

permit writers should be as specific as possible for the needs of the watershed where the MS4 

permittee is located. Permittees should be careful when installing new stormwater BMPs to ensure 

that there are not any negative, unintended consequences. 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 61
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5.6 Tracking of Post-Construction Stormwater Control Measures 

Example Permit Provision 

5.6.1 Inventory of Post-Construction Stormwater Control Measures. The permittee must 

continue to maintain an inventory of all post-construction structural stormwater 

control measures installed and implemented at new development and redeveloped 

sites, including both public and private sector sites located within the permit area. 

The inventory must be searchable by property location (either on paper or 

electronic). New entries to the inventory must be made during the site plan review 

and approval process in Part 5.3.1. 

5.6.2 Tracking Information. Each entry to the inventory must include basic information on 

each project, such as project name, owner’s name and contact information, location, 

start/end date, etc. In addition, inventory entries must include the following for 

each project: 

a. Short description of each stormwater control measure (type, number, design or 

performance specifications); 

b. Latitude and longitude coordinates of each stormwater control measure; 

c. Short description of maintenance requirements (frequency of required 

maintenance and inspections); and 

d. Inspection information (date, findings, follow up activities, prioritization of 

follow-up activities, compliance status).

Based on inspections conducted under Part 5.7, the permittee must update the 

inventory as appropriate where changes occur in property ownership or the specific 

control measures implemented at the site. This inventory must be maintained and 

available for review by the permitting authority. 

Example Permit Requirement Rationale for the Fact Sheet 

Creating an inventory of post-construction structural stormwater control measures, including 

tracking of specific information, will first enable permittees to know what control measures they 

are responsible for. Without this information the permittee will not be protecting water quality 

to their full potential since inspections, maintenance, and follow-up changes cannot be 

performed. Tracking information such as the latitude/longitude, maintenance and inspection 

requirements and follow-up will allow the permittee to be able to better allocate their 

resources for those activities that are immediately necessary. Although not required, including 

photographs will help the permittee assess how the control measure has changed since it was 

first created and will likely aid in determining proper maintenance and/or retrofitting 

opportunities if the measure is no longer providing the water quality benefits it was originally 

designed. 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 62
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Recommendations for the Permit Writer 

Permit writers may wish to specifically define the types of structural controls that must be included 

in the inventory. For example, rain barrels may be considered a structural control, but the MS4 likely 

does not need latitude and longitude coordinates of the rain barrels. 

5.7 Inspections and Enforcement 

Example Permit Provision 

5.7.1 Inspection Frequency. To ensure that all stormwater control measures are operating 

correctly and are being maintained as required consistent with its applicable 

maintenance agreement, the permittee must conduct inspections of each project 

site covered under Part 5.2 performance standards, [insert inspection frequency, 

e.g., at least one time during the permit term, 20% of sites per year, etc.]. The 

inspections must be in accordance with those specified in the [insert State manual 

that describes the maintenance of control measures]. A description of inspection 

procedures must be included in the SWMP document. 

5.7.2 Post-Construction Inspection. Within [insert deadline, e.g., 1 week, 2 weeks, etc.] of 

completion of construction of any project required to meet the Section 5.2 

performance standards, the permittee must conduct a post-construction inspection 

to verify that the permittee’s performance standards have been met. The permittee 

must include in its SWMP a procedure for being notified by construction 

operators/owners of their completion of active construction so that the postconstruction inspection may be conducted. 

5.7.3 Inspection Reports. The permittee must document its inspection findings in an 

inspection report. Each inspection report must include: 

a. Inspection date; 

b. Name and signature of inspector; 

c. Project location (street address, latitude/longitude, etc.) and inventory 

reference number (from inventory established in Section 5.6.1) 

d. Current ownership information (for example, name, address, phone number, 

fax, and email) 

e. A description of the condition of the structural stormwater control measure 

including the quality of: vegetation and soils; inlet and outlet channels and 

structures; embankments, slopes, and safety benches; catch basins; spillways, 

weirs, and other control structures; and sediment and debris accumulation in 

storage and forebay areas as well as in and around inlet and outlet structures; 

f. Photographic documentation of all critical structural stormwater control 

measure components; and 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 63
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g. Specific maintenance issues or violations found that need to be corrected by the 

property owner or operator along with deadlines and reinspection dates. 

The permittee must document and maintain records of inspection findings and 

enforcement actions and make them available for review by the permitting 

authority. 

Example Permit Requirement Rationale for the Fact Sheet 

Inspection of post-construction control measures is key to ensuring the protection of water 

quality. If control measures are not inspected and maintained they could become sources of 

pollution rather than reducing pollution. By including detailed information in the inspection 

report, the permittee can better determine if maintenance is required and the permittee can 

have a snapshot of sorts to know the status of their control measures to prioritize funding. 

Recommendations for the Permit Writer 

Permit writers should clearly specify the requirements for inspections. Inspecting and properly 

maintaining structural stormwater controls to ensure they are working as designed is just as 

important as installing them in the first place. By having specific requirements, permittees will be 

reminded that they must allocate resources to ensure control measures are properly maintained 

and functioning. The permit writer may also want to add a prioritization scheme to the requirement 

to help the permittee determine what maintenance activities are priorities for protecting water 

quality and which ones are minor changes. 

5.8 Retrofit Plan 

Example Permit Provision 

5.8.1 The permittee must develop a plan to retrofit existing developed sites that are 

impacting water quality. The retrofit plan must be developed within [insert deadline, 

such as within two years of permit issuance] and must emphasize controls that 

infiltrate, evapotranspire, or harvest and use stormwater discharges. The plan must 

include21: 

a. An inventory of potential retrofit locations, which considers, at a minimum: 

 Locations that contribute pollutants of concern to an impaired waterbody 

 Locations that contribute to receiving waters that are significantly eroded 

 Locations that are tributary to a sensitive ecosystem or protected area 

 Locations that are tributary to areas prone to flooding 

 

21 Orange County Municipal Stormwater Permit (Section F.3.d) 

(www.waterboards.ca.gov/sandiego/water_issues/programs/stormwater/oc_stormwater.shtml) 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 64
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b. An evaluation and ranking of the inventoried locations to prioritize retrofitting 

which includes, at a minimum: 

 Feasibility 

 Cost effectiveness 

 Pollutant removal effectiveness 

 Impervious area potentially treated 

 Maintenance requirements 

 Landowner cooperation 

 Neighborhood acceptance 

 Aesthetic qualities, and 

 Efficacy at addressing concern. 

Example Permit Requirement Rationale for the Fact Sheet 

It is clear that we cannot protect the nation’s waters without also addressing degradation 

caused by stormwater discharges from existing developed sites. For that reason stormwater 

programs must include substantive retrofit provisions. 

It is possible and reasonable to significantly improve water quality in many urban receiving 

waters. This requires more than just a new development and redeveloped sites program, 

however, which at best can only hold the line. To actually improve the quality of receiving 

waters it is necessary to mitigate discharges from existing developed sites, which generally 

means implementation of measures to bring about the retrofit the stormwater control 

measures at existing sites to retain most stormwater on site. 

In addition, research indicates that most streambank restoration projects that actively stabilize 

eroding channels should not be implemented until after hydrologic retrofits have been completed 

that restore the hydrologic regime not concurrently with the implementation of the retrofits. 

Municipal projects, such as traffic calming sites could also include stormwater retrofit components, 

such as curb bump outs that include bioretention features, rain gardens, and curb cuts. 

Information on retrofit options and the development of a retrofit plan can be found in the 

Center for Watershed Protection’s guidance on Urban Stormwater Retrofit Practices (available 

at www.cwp.org as Manual No. 3 under the Urban Subwatershed Restoration Manual Series). 

Recommendations for the Permit Writer 

Permittees may need a permit term or two to adequately develop and implement a retrofit plan. 

Some permittees may not be ready to have retrofit plans as part of their requirements. It is up to 

the permit writer to make this determination based on the specific information they have available 

on current programs. A retrofit plan should assess the areas where retrofitting is appropriate and 

will result in increased water quality protection and restoration. The permit writer should determine 

Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 65
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Chapter 5: Post-Construction or Permanent/Long-term Stormwater Control Measures 66

the appropriate timeframe and language for a retrofit plan. For example, if the permittee was 

already required to develop a retrofit plan in a previous permit term the permit may specify a 

schedule for implementation rather than development.
CHAPTER 6: POLLUTION PREVENTION/GOOD HOUSEKEEPING

Introduction 

Included Concepts

► Municipal facility and 

control inventory 

► Facility assessment 

► Development of facilityspecific stormwater 

management SOPs and 

Implementation of facility 

stormwater controls 

► Storm sewer system 

maintenance activities 

► Flood management 

► Pesticide, herbicide, and 

fertilizer application and 

management 

► Training and education 

► Contractor requirements 

and oversight 

Federal stormwater regulations (see 40 CFR 122.34(b)(6) and 40 

CFR 122.26(d)(2)(iv)(A)) require the operator of a regulated MS4 

community to develop a program to: 

 Prevent or reduce the amount of stormwater pollution 

generated by municipal operations and conveyed into 

receiving waters. 

 Train employees on how to incorporate pollution 

prevention/good housekeeping techniques into 

municipal operations. 

 Identify appropriate control measures and measurable 

goals for preventing or reducing the amount of 

stormwater pollution generated by municipal 

operations. 

The first step for the permittee is to evaluate and assess the areas 

and municipal facilities that it controls in order to determine which 

activities may currently have a negative impact on water quality and 

to find solutions for these activities. The simplest solution is to limit 

the number of activities that are conducted outside and exposed to 

stormwater. 

Storm sewer systems need maintenance to ensure that structures within the storm sewer that are 

meant to reduce pollutants do not become sources of pollution. Regularly maintaining catch basins and 

cleaning storm sewer pipes prevent the accumulation of pollutants that are later released during rain 

events as well as blockages, backups, and flooding. Most permittees have an existing program to 

maintain the storm sewer infrastructure. EPA notes, however, that some of these programs have 

tended to focus on flood avoidance and complaint response rather than reducing water quality impacts 

from stormwater discharges. 

The MS4 permit must require that the system be maintained to prevent the discharge of pollutants into 

receiving waters. System mapping and a schedule of regular maintenance are key to a successful 

pollution prevention program. EPA recommends establishing a tiered maintenance schedule for the 

entire storm sewer system area, with the highest priority areas being maintained at the greatest 

frequency. Priorities should be driven by water quality concerns and can be based on the land use 

within the MS4 area, the condition of the receiving water, the amount and type of material that typically 

accumulates in an area, or other location-specific factors. It is also advisable to use spill and illicit 

discharge data to track areas that may require immediate sewer infrastructure maintenance. It is also 

important for material that is collected to be disposed of in a responsible manner. 

Chapter 6: Pollution Prevention/Good Housekeeping 67 
MS4 Permit Improvement Guide 

The procedures for storm sewer system operation and maintenance must be documented in the 

permittee’s SOPs or similar type of documents, which are part of the permittee’s SWMP. Employee 

training to carry out these pollution prevention measures is a required component of the program. The 

pollution prevention/good housekeeping/maintenance activities should be documented and, where 

possible, quantified (e.g., number and location of inspections and clean-outs, type and quantity of 

materials removed). Having permittees characterize the quantity, location, and composition of 

pollutants removed from catch basins can provide useful data that can later be used to assess the 

program’s overall effectiveness, identify illicit discharges, and help the permittee better prioritize 

implementation activities in the future. 

Specific pollution prevention requirements related to pollutant-generating activities such as landscaping 

techniques (including the application of pesticides, herbicides, and fertilizer) and operating and 

maintaining public streets, should also be included in the permit where applicable. For example, typical 

pollutants associated with street repair and maintenance include heavy metals, chlorides, hydrocarbons 

(e.g., benzene, toluene, ethylbenzene, xylene), concrete dust, sand, deicers, sediment, and trash. The 

permitting authority should consider requiring alternative landscaping practices such as integrated pest 

management (IPM), xeriscaping, or mechanical (non-chemical) removal of unwanted plants. Other 

landscaping controls, such as mulch management, chemical storage, reduction of soil compaction, and 

erosion control, should also be considered. Training and educating municipal and contracted staff is also 

important to ensure that everyone is knowledgeable and proficient in the newest and most effective 

approaches to minimizing pollutant discharges from municipal facilities and activities. 

Additionally, permits should require that water quality be considered when designing flood 

management projects, and that existing structural flood control devices are evaluated to determine if 

retrofitting the device to remove/reduce pollutants from stormwater is necessary and practicable. 

6.1 Municipal Facility and Control Inventory 

Example Permit Provision 

6.1.1 Development of a Municipal Facility and Stormwater Control Inventory – The 

permittee must continue to update and maintain an inventory of municipally-owned 

or operated facilities and stormwater controls, including but not limited to the 

following: 

 Composting facilities 

 Equipment storage and maintenance facilities 

 Fuel farms 

 Hazardous waste disposal facilities 

 Hazardous waste handling and transfer facilities 

 Incinerators 

 Landfills 

 Landscape maintenance on municipal property 

 Materials storage yards 

Chapter 6: Pollution Prevention/Good Housekeeping 68
MS4 Permit Improvement Guide 

 Pesticide storage facilities 

 Public buildings, including schools, libraries, police stations, fire stations, 

municipal buildings, and similar buildings 

 Public parking lots 

 Public golf courses 

 Public swimming pools 

 Public works yards 

 Recycling facilities 

 Salt storage facilities 

 Solid waste handling and transfer facilities 

 Street repair and maintenance sites 

 Vehicle storage and maintenance yards 

 Municipally-owned and/or maintained structural stormwater controls 

6.1.2 Documentation– The list of municipally-owned or operated facilities and stormwater 

controls must be maintained and available for review by the permitting authority. 

6.1.3 Mapping – On a map of the area covered by the MS4 permit, the permittee must 

identify where the municipally-owned or operated facilities and stormwater controls 

are located. The map must identify the stormwater outfalls corresponding to each of 

the facilities as well as the receiving waters to which these facilities discharge. The 

permittee must also identify the manager of each facility and their contact 

information. The map must be maintained and updated regularly and be available 

for review by the permitting authority. 

Example Permit Requirement Rationale for the Fact Sheet 

Municipally-owned or operated facilities serve as hubs of activity for a variety of municipal staff 

from many different departments. Some municipalities will have one property at which all 

activities take place (e.g., the municipal maintenance yard), whereas others will have several 

specialized facilities such as those listed above. A comprehensive list and map of such facilities 

will help staff responsible for stormwater compliance build a better awareness of their locations 

within the MS4 service area and their potential to contribute stormwater pollutants. The facility 

inventory will also serve as a basis for setting up periodic facility assessments (see Part 6.2) and 

developing, where necessary, facility stormwater pollution prevention plans (see Part 6.3). 

Recommendations for the Permit Writer 

Permit writers should tailor the facilities listed in the assessment as best they can to include the 

facilities most likely to be owned or operated by the permittee. It is highly likely that some of the 

facilities listed in the Permit Requirement would not apply to most non-traditional and/or nonmunicipal MS4s. 

Chapter 6: Pollution Prevention/Good Housekeeping 69
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6.2 Facility Assessment 

Permit Requirement 

6.2.1 Municipally-owned or operated facility assessment: 

a. Comprehensive Assessment of Pollutant Discharge Potential –The permittee 

must review, reassess, and update the comprehensive assessment of all 

municipally-owned or operated facilities identified in Part 6.1 [insert frequency, 

e.g., annually] for their potential to discharge in stormwater the following 

typical urban pollutants: sediment, nutrients, metals, hydrocarbons (e.g., 

benzene, toluene, ethylbenzene and xylene), pesticides, chlorides, and trash. 

Other pollutants may be associated with, but not generated directly from, the 

municipally-owned or operated facilities, such as bacteria, chlorine, organic 

matter, etc. Therefore, the permittee must determine additional pollutants 

associated with its facilities that could be found in stormwater discharges. A 

description of the assessment process must be included in the SWMP document. 

b. Identification of “High Priority” Facilities – Based on the Part 6.2.1.a 

comprehensive assessment, the permittee must identify as “high-priority” those 

facilities that have a high potential to generate stormwater pollutants. Among 

the factors that must be considered in giving a facility a high priority ranking is 

the amount of urban pollutants stored at the site, the identification of 

improperly stored materials, activities that must not be performed outside (e.g., 

changing automotive fluids, vehicle washing), proximity to waterbodies, poor 

housekeeping practices, and discharge of pollutant(s) of concern to impaired 

water(s). High priority facilities must include the permittee’s maintenance 

yards, hazardous waste facilities, fuel storage locations, and any other facilities 

at which chemicals or other materials have a high potential to be discharged in 

stormwater. 

c. Documentation of Comprehensive Assessment Results – The permittee must 

document the results of the assessments and maintain copies of all site 

evaluation checklists used to conduct the comprehensive assessment. The 

documentation must include the results of the permittee’s initial assessment, 

any identified deficiencies and corrective actions taken, and a list of the “high 

priority” facilities identified per Part 6.2.1.b. 

Example Permit Requirement Rationale for the Fact Sheet 

The initial (“first time”) comprehensive assessment is necessary to identify which of the 

municipality’s facilities are most likely to contribute stormwater pollutants and which are in 

need of stormwater controls. The assessments will involve a detailed site inspection that can 

identify improperly stored materials, activities that should not be performed outside (e.g., 

changing automotive fluids, vehicle washing), and poor housekeeping practices. 

Chapter 6: Pollution Prevention/Good Housekeeping 70
MS4 Permit Improvement Guide 

Recommendations for the Permit Writer 

If the permitting authority has an established site inspection protocol to be used in the comprehensive 

assessment, it should be included and referenced here. The list of pollutants in this section should be 

modified or expanded based on pollutants of concern in the permitting authority’s jurisdiction. 

6.3 Development of Facility-Specific Stormwater Management SOPs 

and Implementation of Facility Stormwater Controls 

Example Permit Provision 

6.3.1 Facility-specific Stormwater Management SOPs for “High Priority” Facilities: 

a. For each “high priority” facility or operation identified in Part 6.2, the permittee 

must develop a site-specific SOP that identifies stormwater controls (i.e., 

structural and non-structural controls, and operational improvements) to be 

installed, implemented, and maintained to minimize the discharge of pollutants in 

stormwater. At a minimum, the facility-specific SOP must include the stormwater 

control measures described below in Part 6.3.2, as well as inspection and visual 

monitoring procedures and schedules described in Part 6.3.3. 

b. A copy of the facility-specific stormwater management SOP must be maintained 

and be available for review by the permitting authority. The SOP must be kept 

on-site at each of the municipally-owned or operated facilities’ offices for which 

it was completed. The SOP must be updated as necessary. 

c. The permittee must install, implement, and maintain all stormwater controls 

required per Part 6.3.2 of this permit and included in the facility’s site-specific SOP. 

6.3.2 Stormwater Controls for “High Priority” Facilities – The following stormwater 

controls must be implemented at all “high priority” municipally-owned or operated 

facilities identified in Part 6.2. A description of any controls included in this part and 

any standard operating procedures developed to comply with this part must be 

included as part of the of each facility’s SOP: 

a. General good housekeeping – The following good housekeeping practices must 

be implemented for all facilities identified as “high priority”: 

1. The permittee must keep all municipally-owned or operated facilities neat 

and orderly, minimizing pollutant sources through good housekeeping 

procedures and proper storage of materials. 

2. Materials exposed to stormwater must be covered where feasible (without 

creating additional impervious surfaces, if possible). 

b. De-icing material storage – The permittee must store salt and other de-icing 

materials in a permanent storage structure, unless stormwater runoff from the 

storage piles is not discharged, or if discharges from the piles are authorized 

under another stormwater permit. If a permanent storage structure is required 

but does not exist, one must be built within [insert timeframe], and seasonal 

Chapter 6: Pollution Prevention/Good Housekeeping 71
MS4 Permit Improvement Guide 

tarping must be used as an interim control measure until the permanent 

structure is completed. If a permanent storage facility is not feasible, the 

permittee must provide a rationale to the permitting authority as to why and 

what alternate BMPs will be utilized instead. 

 Where a permanent storage structure is present, the permittee must perform 

regular maintenance and inspections of the permanent storage structure. 

c. Fueling operations – The permittee must continue to implement standard 

operating procedures for vehicle fueling and receiving of bulk fuel deliveries at 

municipally-owned or operated facilities with the goal of reducing the likelihood 

of spills, and providing spill controls in the event that accidental spills do occur. 

d. Vehicle maintenance – The permittee must continue to implement a standard 

operating procedure for vehicle maintenance and repair activities that occur at 

municipally-owned or operated facilities with the goal of reducing the likelihood 

of spills or releases and providing controls in the event that accidental spills do 

occur. The standard operating procedures must include regular inspections of all 

maintenance areas and activities. 

e. Equipment and vehicle washing – The discharge of equipment and vehicle wash 

wastewater to the MS4 or directly to receiving waters from municipal facilities is 

prohibited. The permittee may meet this requirement by either installing a 

vehicle wash reclaim system, capturing and hauling the wastewater for proper 

disposal, connecting to sanitary sewer (where applicable and approved by local 

authorities), ceasing the activity, and/or applying for and obtaining a separate 

stormwater permit.22

6.3.3 Inspections and Visual Monitoring: 

a. Weekly visual inspections – The permittee must perform weekly visual 

inspections to ensure materials and equipment are clean and orderly, and to 

minimize the potential for pollutant discharge. The permittee must look for 

evidence of spills and immediately clean them up to prevent contact with 

precipitation or runoff. The weekly inspections must be tracked in a log for 

every facility, and records kept with the SWMP document. The inspection 

report must also include any identified deficiencies and the corrective actions 

taken to fix the deficiencies. 

b. Quarterly comprehensive inspections – At least once per quarter, a 

comprehensive inspection of “high priority” facilities, including all stormwater 

controls, must be performed, with specific attention paid to waste storage 

areas, dumpsters, vehicle and equipment maintenance/fueling areas, material 

handling areas, and similar potential pollutant-generating areas. The quarterly 

inspection results must be documented and records kept with the SOP 

document. This inspection must be done in accordance with the developed 

SOPs. The inspection report must also include any identified deficiencies and the 

corrective actions taken to fix the deficiencies. 

 

22 New Jersey Tier A Phase II MS4 Permit (NJ0141852) (www.state.nj.us/dep/dwq/pdf/Tier_A_final.pdf) 

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c. Quarterly visual observation of stormwater discharges – At least once per 

quarter, the permittee must visually observe the quality of the stormwater 

discharges from the “high priority” facilities (unless climate conditions preclude 

doing so, in which case the permittee must attempt to evaluate the discharges 

four times during the wet season). Any observed problems (e.g., color, foam, 

sheen, turbidity) that can be associated with pollutant sources or controls must 

be remedied within three days or before the next storm event, whichever is 

sooner. Visual observations must be documented, and records kept with the 

SOP document. This inspection must be done in accordance with the developed 

SOPs. The inspection report must also include any identified deficiencies and the 

corrective actions taken to fix the deficiencies. 

Example Permit Requirement Rationale for the Fact Sheet 

Each municipal facility will require a different set of control measures depending on the nature 

of activities that occur there and the types of materials that are stored and used. Developing 

and maintaining a site-specific SOP for each facility will help to ensure that employees 

responsible for facility operation are aware of the stormwater controls required for the site. 

There are a number of storage areas and activities that are common at municipal facilities that 

have a high potential for polluting stormwater: 

 Deicing materials, particularly road salt, are easily liberated and transported by rainfall, and 

constituents such as chloride are not removed by most stormwater controls. 

 Fueling and vehicle maintenance and storage areas are prone to spills and drips of various 

automotive fluids. 

 Equipment and vehicle washing areas are designed to mix water with dirt and hydrocarbons, 

requiring special treatment of the wastewater (including pretreatment and diversion to the 

sanitary sewer, if allowed) and protection of wash areas from rainfall and runoff. 

The best way to avoid pollutant discharges from these sources is to keep precipitation and 

runoff from coming into contact with stored chemicals and activity areas that use chemicals and 

materials, which can become sources of stormwater pollutants. For example, the permittee 

must cover stockpiles, create dedicated structures for stored materials, build berms around 

areas of pavement to prevent clean runoff from contacting contaminated areas, and maintain a 

minimum distance between stockpiles and stormwater infrastructure and receiving waters. 

These are just a few of the ways in which these potential pollutant sources can be protected 

from precipitation and runoff. 

The permit requires that comprehensive site inspections be conducted quarterly, which is an 

appropriate frequency to ensure that material stockpiles that might be moved or utilized on a 

seasonal basis are protected from precipitation and runoff. Also, quarterly inspections will 

allow inspectors to observe different types of operations that occur at different times of the 

year (e.g., landscape maintenance crews are less active in the winter). Quarterly visual 

observations are required so that inspectors can see in real time the qualitative nature of the 

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MS4 Permit Improvement Guide 

stormwater discharge and so that corrective action can be taken where necessary to improve 

on-site stormwater controls. 

The permit also specifies that inspection procedures, results, and controls for each facility be 

documented to ensure that the site inspections are consistent and that maintenance of 

stormwater controls remains part of the municipality’s standard operating procedures. The 

requirement for an inspection log will allow the permitting authority to verify that periodic site 

inspections have been performed. 

Recommendations for the Permit Writer 

Neither Phase I nor Phase II regulations specifically require that MS4 permittees develop facilityspecific stormwater management SOPs. However, both Phase I and Phase II require that permittees 

prevent or reduce pollutant discharge in stormwater from municipal facilities and activities. 

Requiring permittees to assess high priority facilities and develop appropriate controls for each is an 

effective way of requiring permittees to address potential sources of pollutants at facilities. 

When setting frequency for facility inspections (see Part 6.3.3), the permit writer should consider 

the number of facilities and the size/complexity of the sites to ensure that enough time is available 

to complete the assessments. 

The list of specific stormwater controls for municipal facilities will vary from place to place based on 

local and watershed priorities and climate considerations. The permit writer should specify 

stormwater controls that are appropriate for the local conditions. For example, if a permittee uses 

satellite locations for temporary storage of deicing materials during snow events, the permit writer 

may want to consider options other than the permanent storage requirement if the permittee uses 

the piles within a certain time frame and the piles are covered by temporary tarping or a similar 

control. 

6.4 Storm Sewer System Maintenance Activities 

Example Permit Provision 

6.4.1 MS4 catch basin maintenance 

a. Assessment/prioritization of catch basins – The permittee must assign a priority 

to each of its catch basin inlets within its jurisdiction as one of the following: 

 Priority A – Catch basins that are designated as consistently generating the 

highest volumes of trash and/or debris 

 Priority B – Catch basins that are designated as consistently generating 

moderate volumes of trash and/or debris 

 Priority C – Catch basins that are designated as generating low volumes of 

trash and/or debris 

 The permittee must use information compiled from citizen complaints/reports 

to help in the determination of the appropriate priority level. A description of 

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the prioritization scheme must be included in the SWMP. 

b. Catch basin inspection and cleaning 

1. Based on the priorities assigned in Part 6.4.1.a., the permittee must inspect 

and clean catch basins in accordance with the following schedule: 

 Priority A – [Insert cleanout frequency, e.g., 3 times per year] 

 Priority B – [Insert cleanout frequency, e.g., 2 times per year] 

 Priority C – [Insert cleanout frequency, e.g., 1 time per year] 

 The permittee must develop a catch basin cleaning schedule based on the 

frequency specified in this permit, along with a list of each of its catch basins 

and the priority assigned to them per Part 6.4.1.a. 

2. In addition to catch basin cleanings performed above, the permittee must 

ensure that any catch basin that is inspected and found to be between one 

third and one half full of trash and/or debris must be cleaned within [Insert 

cleanout frequency e.g., 1 week of discovery].23 The permittee must 

maintain a log of all maintenance performed. 

3. The permittee must document that it has performed all required catch basin 

cleanings in a log that is to be made available for review by the permitting 

authority upon request. 

c. Catch basin labeling – The permittee must ensure that each catch basin includes 

a legible stormwater awareness message (e.g., a label, stencil, marker, or precast message such as “drains to the creek” or “only rain in the drain”). Catch 

basins with illegible or missing labels must be recorded and re-labeled within 

[insert number of days] of inspection. 

d. Maintenance of surface drainage structures – The permittee must visually 

monitor permittee-owned open channels and other drainage structures for 

debris at least [specify frequency, e.g., once per year] and identify and prioritize 

problem areas, such as those with recurrent illegal dumping, for inspection at 

least [specify frequency, e.g., three times per year]. Removal of trash and debris 

from open channels and other drainage structures must occur [insert frequency 

of open channel/drainage structure cleaning, e.g., annually]. The permittee must 

document its drainage structure maintenance in a log that is to be made 

available for review by the permitting authority upon request. 

e. Disposal of waste materials – The permittee must develop a procedure to 

dewater and dispose of materials extracted from catch basins. This procedure 

must ensure that water removed during the catch basin cleaning process and 

waste material will not reenter the MS4. 

6.4.2 Municipal activities and operations 

a. Assessment of municipal activities and operations 

 

23 EPA’s Office of Research and Development documented a threshold sump level of 1⁄2 as a break point where 

solids retainage was either erratic or negative (Catchbasin Technology Overview and Assessment #EPA-600/2-77-

051 1977). 

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1. The permittee must maintain and revise as necessary the operation and 

maintenance (O&M) activity assessment. The following municipal O&M 

activities must be included in the assessment for their potential to discharge 

pollutants in stormwater: 

 Road and parking lot maintenance, including pothole repair, pavement 

marking, sealing, and re-paving 

 Bridge maintenance, including re-chipping, grinding, and saw cutting 

 Cold weather operations, including plowing, sanding, and application of 

deicing compounds and maintenance of snow disposal areas 

 Right-of-way maintenance, including mowing, herbicide and pesticide 

application, and planting vegetation 

 Municipally-sponsored events such as large outdoor festivals, parades, 

or street fairs 

2. The permittee must identify all materials that could be discharged from each 

of these O&M activities. Typical pollutants associated with these activities 

include metals, chlorides, hydrocarbons (e.g. benzene, toluene, 

ethylbenzene, xylene), sediment, and trash. 

3. The permittee must develop a set of pollution prevention measures that, 

when applied during municipal O&M activities, will reduce the discharge of 

pollutants in stormwater. These pollution prevention measures must 

include, at a minimum: 

 Replacing materials/chemicals with more environmentally benign 

materials or methods (e.g., use mechanical methods vs. herbicides, or 

use water-based paints or thermoplastics rather than solvent-based 

paints for stripping) 

 Changing operations to minimize the exposure or mobilization of 

pollutants (e.g., mulch, compost or landfill grass clippings) to prevent 

them from entering surface waters 

 Placing barriers around or conducting runoff away from deicing chemical 

storage areas to prevent discharge into surface waters), consistent with 

Part 6.3.2.b 

 [If available in your particular State or the municipality, insert relevant 

section of SWMP, or other relevant document, that includes specific 

stormwater controls that must be used.] 

4. The permittee must develop and implement a schedule for instituting the 

pollution prevention measures. At a minimum, with respect to all roads, 

highways, and parking lots with more than 5,000 square feet of pollutantgenerating impervious surface area that are owned, operated, or 

maintained, the permittee must implement all pollution prevention 

measures by [insert deadline]. 

5. The results of the assessments and pollution prevention measures, including 

schedules for implementation, must be documented and made available for 

review by the permitting authority upon request. 

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b. Inspection of pollution prevention measures – All pollution prevention measures 

implemented at municipal facilities must be visually inspected [insert frequency, 

e.g., monthly or quarterly] to ensure they are working properly; a log of 

inspections must be maintained and made available for review by the permitting 

authority upon request. 

6.4.3 Street Sweeping and Cleaning 

a. The permittee must continue to evaluate and rate all municipally-owned streets, 

roads, and public parking lots within their jurisdiction. The permittee must 

include in the evaluation the sweeping frequency, timing, and efficiency of 

existing street sweeping programs. The street sweeping frequency must be 

based on land use, trash and stormwater pollutant levels generated. At a 

minimum, the following areas must be regarded as “high priority,” for sweeping 

activities while the “medium priority” and “low priority” areas are 

recommended: 

 High priority – Streets, road segments, and public parking lots designated as 

high priority include, but are not limited to, high traffic zones, commercial 

and industrial districts, shopping malls, large schools, high-density 

residential dwellings, sport and event venues, and plazas. This designation 

must include areas that consistently accumulate high volumes of trash, 

debris, and other stormwater pollutants. 

 Medium priority – Streets, road segments and public parking lots designated 

as medium priority include, but are not limited to, medium traffic zones; 

warehouse districts; and light, small-scale commercial and industrial areas. 

 Low priority – Streets and road segments designated as low priority include, 

but are not limited to, light traffic zones and residential zones. 

b. The permittee must show on a map of its service area how the streets, roads, 

and public parking lots have been rated in accordance with Part 6.4.3.a. 

c. Implementing sweeping schedules – The permittee must sweep 

streets/roads/public parking lots in accordance with the following frequency: 

 High priority – average of at least [insert frequency, e.g., twice per month] 

 Medium priority – average of at least [insert frequency, e.g., once per month] 

 Low priority – [insert frequency, e.g., twice per year] 

 If a permittee’s existing overall street sweeping effort provides equivalent or 

greater street sweeping frequency relative to the requirements above, the 

permittee may continue to implement its existing street sweeping program. 

d. For areas where street sweeping is technically infeasible (e.g., streets without 

curbs), the permittee must increase implementation of other trash/litter control 

procedures to minimize pollutant discharges to storm drains and creeks. The 

permittee must show on its Part 6.4.3.b map the location of these areas. 

e. Sweeping equipment selection and operation 

1. When replacing existing sweeping equipment, the permittee must select and 

operate high-performing sweepers that are efficient in removing pollutants, 

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MS4 Permit Improvement Guide 

including fine particulates, from impervious surfaces. 

2. The permittee must follow equipment design performance specifications to 

ensure that street sweeping equipment is operated at the proper equipment 

design speed with appropriate verification, and that it is properly 

maintained. 

3. The permittee must operate sweepers to optimize pollutant removal by 

permitting sweepers access to the curb through the use of parking 

restrictions that clear the curb or through effective public outreach to 

inform citizens of sweeping days and times so that voluntary curb clearing 

can occur. 

f. Sweeper Waste Material Disposal – The permittee must develop a procedure to 

dewater and dispose of street sweeper waste material. This procedure must 

ensure that water and material will not reenter the MS4. 

g. Operator training – Street sweeper operators must be trained to enhance 

operations for water quality benefit. 

h. The permittee must include the following in the SWMP and update as changes 

are made: 

1. A description of the street sweeping frequency and any significant changes 

in the sweeping frequency map, along with the basis for those changes 

2. The types of sweepers used 

3. A summary of the proper sweeping operation verification results and street 

sweeping methods, including the way in which the permittee specifies and 

confirms the rate or speed at which street miles are covered by sweeper 

operators 

4. The use of additional resources in sweeping seasonal leaves or pick-up of 

other material 

5. A description of the methods for addressing areas identified in Part 6.4.3, 

considered infeasible for street sweeping 

6.4.4 Maintenance of municipally-owned and/or maintained structural stormwater 

controls 

a. The permittee must inspect at least [insert frequency, e.g., yearly], and maintain 

if necessary, all municipally-owned or maintained structural stormwater 

controls. The permittee must also maintain all green infrastructure practices 

through regularly scheduled maintenance activities. 

Example Permit Requirement Rationale for the Fact Sheet 

MS4 Maintenance 

Traditional municipal storm drain systems were designed to quickly collect and convey runoff to 

receiving waters. The purpose of catch basin, inlet, and storm drain cleanouts is to prevent 

blockages, flooding, and reduce pollution. 

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MS4 Permit Improvement Guide 

Fine particles and pollutants from run-on, atmospheric deposition, vehicle emissions, breakup of 

street surface materials, littering, and sanding can accumulate along the curbs of roads in 

between rainfall events. This results in the accumulation of pollutants such as sediment, 

nutrients, metals, hydrocarbons, bacteria, pesticides, trash and other toxic chemicals. Storm 

drain maintenance is often the last opportunity to remove pollutants before they enter the 

storm drain system. Because they effectively trap solids, they need to be cleaned out 

periodically to prevent those materials from being transported by high stormwater flows. By 

doing so the MS4 will prevent trash and litter from ultimately becoming sources of marine 

debris, which is any man-made, solid material that enters waterways either directly or 

indirectly. 

The permit includes a priority ranking approach for catch basins so that municipal resources are 

directed to the areas and structures that generate the most pollutants. A priority ranking 

system is required because some catch basins will accumulate pollutants faster than others 

based on the nature of the drainage area and whether controls are present upstream of the 

catch basin. Catch basins with the highest accumulations will need to be cleaned more often 

than those with low accumulations. The permit language also includes a requirement that 

triggers catch basin cleaning when a catch basin is one-third full. 

Proper storm drain system cleanout includes vacuuming or manually removing debris from 

catch basins; vacuuming or flushing pipes to increase capacity and remove clogs; removing 

sediment, debris, and overgrown vegetation from open channels; and repairing structures to 

ensure the integrity of the drainage system. It is important to conduct regular inspections of all 

storm sewer infrastructure and perform maintenance as necessary. Though these activities are 

intended to ensure that the sewer system is properly maintained and that any accumulated 

pollutants are removed prior to discharge, if not properly executed, cleanout activities can 

result in pollutant discharges. In selecting maintenance practices, the permittee must carefully 

evaluate each with an eye towards stormwater pollution potential to minimize unintended 

pollutant discharges, such as the use of flushing storm drain pipes to remove debris without 

recapturing the debris further down the pipe. 

The materials removed from catch basins may not reenter the MS4. The material must be 

dewatered in a contained area and the water treated with an appropriate and approved control 

measure or discharged to the sanitary sewer. The solid material will need to be stored and 

disposed of properly to avoid discharge during a storm event. Some materials removed from 

storm drains and open channels may require special handling and disposal, and may not be 

authorized to be disposed of in a landfill. 

Street Sweeping and Cleaning

Street and parking lot sweeping is a practice that most municipalities initially conducted for 

aesthetic purposes. However, the water quality benefits are now widely recognized. Street 

sweeping also prevents particulate matter associated with road dust from accumulating on 

public streets and washing into storm drains. 

The permit language addresses a number of important factors that impact the effectiveness of a 

street sweeping program. The first factor is the type of equipment used; the permit language 

stipulates that when equipment needs to be replaced, high-performance sweepers are purchased 

preferentially. Street sweeping has traditionally been more effective at removing large-sized 

particles, but new equipment has been developed to remove smaller, fine-grained particles. 

Mechanical sweepers (broom-type) are usually the least expensive and are better suited to pick up 

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MS4 Permit Improvement Guide 

large-grained sediment. Vacuum and regenerative air sweepers are better at removing finegrained sediment particles, but they are more expensive. Removal efficiency can be improved 

through tandem sweeping (i.e., two sweepers sweeping the same route, with one following the 

other to pick up missed material), or if the street sweeper makes multiple passes on a street. 

The second factor influencing street sweeping effectiveness is the way in which the equipment 

is operated; the permit specifies that equipment be operated according to the manufacturers' 

operating instructions by operators who have been trained to sweep in accordance with the 

Permit Requirements in order to protect water quality. 

The third determining factor is the degree to which parked cars block sweeper access to the curb; 

one of the best ways to ensure access to the curb is to establish parking restrictions based on 

sweeping schedules and to inform residents of the schedule so they can voluntarily move their 

cars. The permit requires that the permittee institute parking restrictions and/or a public 

outreach campaign requesting that cars be parked elsewhere to accommodate sweeping 

schedules. 

Because not all streets are suitable for sweeping (e.g., those that don't have a curb and gutter), 

source controls can be used in place of sweeping in those areas. 

The permittee is required to maintain documentation of sweeping events and characterize the 

quantity and composition of pollutants removed from roadways. Street sweeping data are 

relatively easy to track and maintain, so the permit includes requirements for reporting and 

assessment of the effectiveness of the sweeping activities based on equipment used, miles 

swept, and the amount of materials collected. 

The street sweeping material may not reenter the MS4. The material must be dewatered in a 

contained area and the water treated with an appropriate and approved control measure or 

discharged to the sanitary sewer. The solid material will need to be stored and disposed of 

properly to avoid discharge during a storm event. Some materials may require special handling 

and disposal, and my not be authorized to be disposed of in a landfill. 

Recommendations for the Permit Writer 

MS4 Maintenance 

MS4s should have a specific schedule to clean out their storm drains since it will ensure that the 

debris that is trapped in the system will not move into waterbodies and ultimately become marine 

debris in the ocean. For additional information to include on marine debris go to the EPA's Marine 

Debris website (www.epa.gov/owow/oceans/debris). 

The frequency and timing of visual assessments and cleaning of storm drains and open channels can 

be tailored to local climate conditions. For example, one approach would be to require that visual 

observations and cleanings be conducted before the start of the wet season or before spring 

snowmelt. 

The permitting authority should review and approve dewatering and disposal methods for materials 

removed from catch basins. 

Catch basin labeling is believed to be an effective mechanism for educating residents since it 

involves a direct reminder that that water or other materials which flow into storm drains is not 

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MS4 Permit Improvement Guide 

treated in any way, but instead drains directly to nearby waterways. There are many methods for 

labeling catch basins and the permit writer should work with the permittee to determine the most 

feasible and cost effective method of delivering the “drains to stream” message. 

Street Sweeping and Cleaning 

Street sweeping frequency and timing can be based on climate conditions and seasonal variation in 

pollution loading. For example, in cold climates where sand is used for winter road maintenance, the 

permit language could specify increased sweeping during the winter and prior to the spring snowmelt. 

In areas with a rainy season, sweeping might be timed to occur before the rainy season starts. 

In the fall, sweepers can be used to pick up leaves, as they can contribute 25 percent of nutrient 

loadings in catch basins. If more substantial piles of leaves are found in the community during the 

fall, street sweeping activities should be coordinated with leaf pick-up. Equally important is an early 

spring sweeping before rains begin to pick up sand, de-icing material, and winter debris. More 

frequent sweeping may reduce the need for catch basin cleaning. 

The prioritization of sweeping activities (high, medium, low) should be based on standard categories 

that are based on traffic frequencies and used to determine service levels for the roadways. The 

example provided in the permit language is based on specific information for the location. 

The permitting authority should review and approve dewatering and disposal methods for street 

sweeping material. 

6.5 Flood Management 

Example Permit Provision 

6.5.1 Flood Management Projects – Within [insert deadline, such as two years] of permit 

issuance, the permittee must develop and implement a process to assess the water 

quality impacts in the design of all new flood management projects that are 

associated with the permittee or that discharge to the MS4. This process must 

include consideration of controls that can be used to minimize the impacts to site 

water quality and hydrology while still meeting the project objectives. Beginning 

[insert deadline, such as three years] from date of permit issuance, the permittee 

must assess at least [insert number of projects to be evaluated, such as two] existing 

flood management projects per year to determine whether changes or additions 

should be made to improve water quality. 24 A description of this process must be 

included in the SWMP document. 

 

24 Eastern Washington Phase II MS4 Permit (www.ecy.wa.gov/programs/wq/stormwater/municipal/phaseiiEwa/

MODIFIEDpermitDOCS/EWpermitMODsigned.pdf) 

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Example Permit Requirement Rationale for the Fact Sheet 

This permit requires that existing flood management projects be prioritized and a set number be 

evaluated to identify opportunities for water quality retrofits. This is because the focus of 

stormwater management in the past had been to control flooding and mitigate property 

damage, with less emphasis on water quality protection. These structures may handle a 

significant amount of stormwater and therefore offer an opportunity to modify their design to 

include water quality features for less than the cost of building new controls. This requirement 

applies not only to new flood control projects, but also to existing structures. 

6.6 Pesticide, Herbicide, and Fertilizer Application and Management 

Example Permit Provision 

6.6.1 Landscape maintenance 

a. The permittee must evaluate the materials used and activities performed on 

public spaces such as parks, schools, golf courses, easements, public rights of 

way, and other open spaces for pollution prevention opportunities. 

Maintenance activities for the turf landscaped portions of these can include 

mowing, fertilization, pesticide application, irrigation, etc. Typical pollutants 

include sediment, nutrients, hydrocarbons, pesticides, herbicides and organic 

debris. 

b. The permittee must implement the following practices to minimize landscapingrelated pollutant generation: 

1. Educational activities, permits, certifications, and other measures for 

municipal applicators and distributors. 

2. Integrated pest management measures that rely on non-chemical solutions, 

including 

 Use of native plants, xeriscaping in arid/semi-arid regions (reduces water 

usage and fertilization) 

 Keeping clippings and leaves away from waterways and out of the street 

using mulching, composting, or landfilling 

 Limiting application of pesticides and fertilizers if precipitation is 

forecasted within 24 hours or as specified in label instructions 

 Limiting or replacing pesticide use (e.g., manual weed and insect 

removal) 

 Limiting or eliminating the use of fertilizers, or, if necessary, prohibiting 

application within 5 feet of pavement, 25 feet of a storm drain inlet, or 

50 feet of a waterbody 

 Reducing mowing of grass to allow for greater pollutant removal, but 

not jeopardizing motorist safety 

3. Schedules for chemical application that minimize the discharge of such 

constituents due to irrigation and expected precipitation. 

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MS4 Permit Improvement Guide 

4. The collection and proper disposal of unused pesticides, herbicides, and 

fertilizers.25

Example Permit Requirement Rationale for the Fact Sheet 

The permit focuses on requiring source controls to reduce the amount of chemicals used. The 

permit specifies the use of integrated pest management, selection of native vegetation that is 

naturally adapted to local conditions and therefore requires fewer chemical and water inputs, 

reducing exposure of the chemicals to water by scheduling application according to weather 

forecasts and plant needs, and ensuring that municipal employees who are responsible for 

storing and handling these materials are educated about their use, disposal, and possible 

impacts. 

Recommendations for the Permit Writer 

EPA is currently developing a general permit to control discharges from the application of pesticides 

to or over, including near, waters of the U.S. EPA is working closely with state NPDES and pesticide 

control authorities, the regulated community, and environmental organizations to develop its 

permit that will be required for such discharges beginning in April 2011. It is important to note that 

some of the permit language in this section may need to be altered to be consistent with the 

pesticide permit once it is finalized. For up-to-date information, go to EPA’s website 

(www.epa.gov/npdes/agriculture). 

6.7 Training and Education 

Example Permit Provision 

6.7.1 Employee Training Requirements – Permittees must develop an annual employee 

training program for appropriate employees involved in implementing pollution 

prevention and good housekeeping practices in the preceding Parts. All new hires 

must receive training within the first year of their hire date. This annual training 

must include a general stormwater education component, any new technologies, 

operations, or responsibilities that arise during the year, and the Permit 

Requirements that apply to the staff being trained. A description of the program 

must be maintained for review by the permitting authority. The permittee must also 

identify and track all personnel requiring training and records must be maintained. 

Training must begin [insert deadline] from the effective date of permit authorization. 

 

25 San Diego Phase I MS4 Permit (CAS0108758) (www.swrcb.ca.gov/rwqcb9/water_issues/programs/stormwater/

docs/oc_permit/updates_8_13_09/R9-2009-0002_12Aug09.pdf) 

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Chapter 6: Pollution Prevention/Good Housekeeping 84

Example Permit Requirement Rationale for the Fact Sheet 

The regulations found at 40 CFR 122.34(b)(6) specifically requires that the permittee develop a 

“training component” that trains employees “to prevent and reduce stormwater pollution from 

activities such as park and open space maintenance, fleet and building maintenance, new 

construction and land disturbances, and storm water system maintenance.” This permit 

requires employee training for existing and new employees who are involved in performing 

pollution prevention and good housekeeping practices. All training must include a general 

stormwater educational component, including an overview of the requirements with which the 

municipality needs to comply. The permittee is responsible for identifying which staff must 

attend trainings based on the applicability of the topics listed, and they are required to conduct 

refresher training on an annual basis. 

Recommendations for the Permit Writer 

The topics included in the trainings should take into consideration the types of activities in which the 

municipality engages and the extent to which such activities are performed in-house or contracted. 

6.8 Contractor Requirements and Oversight 

Example Permit Provision 

6.8.1 Requirements for Contractors: 

a. Any contractors hired by the permittee to perform municipal maintenance 

activities must be contractually required to comply with all of the stormwater 

control measures, good housekeeping practices, and facility-specific stormwater 

management SOPs described above. 

b. The permittee must provide oversight of contractor activities to ensure that 

contractors are using appropriate control measures and SOPs. Oversight 

procedures must be described in the SWMP document. 

Example Permit Requirement Rationale for the Fact Sheet 

Many municipalities use third-party contractors to conduct municipal maintenance activities in 

lieu of using municipal employees. Contractors performing activities that can affect stormwater 

quality must be held to the same standards as the permittee. Not only must these expectations 

be defined in contracts between the permittee and its contractors, but the permittee is 

responsible for ensuring, through contractually-required documentation or periodic site visits, 

that contractors are using stormwater controls and following standard operating procedures. 
CHAPTER 7: INDUSTRIAL STORMWATER SOURCES

Introduction 

Phase I MS4 permittees are required to develop and implement an 

inspection and oversight program to monitor and control pollutants 

in stormwater discharges to the MS4 from industrial facilities. 

Regulations addressing industrial stormwater management in Phase 

I MS4 permits is found at 40 CFR 122.26(d)(2)(i)(B, C, E, and F) and 

40 CFR 122.26(d)(2)(iv). Requirements to regulate the stormwater 

discharges from commercial facilities are found at 40 CFR 

122.26(d)(2)(iv)(A). 

This program component typically applies only to Phase I MS4 

permittees as Phase II federal regulations (40 CFR 122.34(b)) do not 

specifically address stormwater discharges from industrial facilities 

and commercial businesses (other than as part of the education and outreach program). However, EPA 

recommends that permit writers consider including requirements pertaining to stormwater discharges 

to the MS4 from industrial sources in Phase II permits to further reduce stormwater pollutants from the 

MS4. 

Phase I MS4 regulations specify that several key elements be included in Phase I MS4 stormwater 

management programs. These elements include: adequate legal authority to require compliance and 

inspect sites, inspection of priority industrial and commercial facilities, establishing control measure 

requirements for facilities that may pose a threat to water quality, and enforcing stormwater 

requirements. In order to implement these requirements, MS4 permits require the development of an 

inventory of facilities and prioritization protocol and adequate staff training to ensure proper inspection 

and enforcement of requirements. 

7.1 Facility Inventory 

Example Permit Provision 

7.1.1 Source Identification 

a. The permittee must continue to maintain an inventory of all industrial and 

commercial sites/sources within its jurisdiction (regardless of ownership) that 

could discharge pollutants in stormwater to the MS4. The inventory must be 

updated [insert frequency, e.g. annually] and available for review by the 

permitting authority upon request. 

b. The inventory must include the following minimum information for each 

industrial and commercial site/source: 

1. Name 

Included Concepts

► Facility inventory 

► Industrial facility 

stormwater control 

measures 

► Industrial and commercial 

facility inspections 

► Staff training 

Chapter 7: Industrial Stormwater Sources 85 
MS4 Permit Improvement Guide 

2. Address 

3. Physical location of storm drain receiving discharge 

4. Name of receiving water 

5. Pollutants potentially generated by the site/source 

6. Identification of whether the site/source is (1) tributary to an impaired 

water body segment (i.e., whether it is listed under Section 303(d) of the 

Clean Water Act) and (2) whether it generates pollutants for which the 

water body segment is impaired 

7. A narrative description including standard industrial classification (SIC) 

codes, which best reflects the principal products or services provided by 

each facility. 

The use of a geolocational database system is highly recommended. 

c. At a minimum, the following sites/sources must be included in the inventory: 

1. Commercial Sites/Sources: 

[insert commercial sources that are a priority such as

 Airplane repair, maintenance, fueling, or cleaning 

 Animal facilities 

 Automobile and other vehicle body repair or painting 

 Automobile (or other vehicle) parking lots and storage facilities 

 Automobile repair, maintenance, fueling, or cleaning 

 Boat repair, maintenance, fueling, or cleaning 

 Building material retailers and storage 

 Cement mixing or cutting 

 Eating or drinking establishments (e.g., restaurants), including food 

markets 

 Equipment repair, maintenance, fueling, or cleaning 

 Golf courses, parks and other recreational areas/facilities 

 Landscaping 

 Marinas 

 Masonry 

 Mobile automobile or other vehicle washing 

 Mobile carpet, drape or furniture cleaning 

 Nurseries and greenhouses 

 Painting and coating 

 Pest control services 

 Pool and fountain cleaning 

 Portable sanitary services 

Chapter 7: Industrial Stormwater Sources 86
MS4 Permit Improvement Guide 

 Power washing services 

 Retail or wholesale fueling] 

2. Industrial Sites/Sources: 

 Industrial Facilities, as defined at 40 CFR § 122.26(b)(14), including those 

subject to the Multi Sector General Permit or individual NPDES permit 

 Facilities subject to Title III of the Superfund Amendments and 

Reauthorization Act (SARA) 

 Hazardous waste treatment, disposal, storage and recovery facilities 

3. All other commercial or industrial sites/sources tributary to an impaired 

water body segment, where the site/source generates pollutants for which 

the water body segment is impaired 

4. All other commercial or industrial sites/sources that the permittee 

determines may contribute a significant pollutant load to the MS426

Example Permit Requirement Rationale for the Fact Sheet 

The permit requires the permittee to develop an inventory of all potential commercial and 

industrial sites/sources that could contribute pollutants to the MS4. A list of specific 

commercial and industrial sites/sources is included in the permit, and additional sites/sources 

can be added if they are likely to discharge a pollutant of concern to an impaired waterbody or 

they are contributing a significant pollutant load to the MS4. 

The inventory information will provide the permittee with information on potential pollutant 

sources that contribute to its MS4 system, and at what locations in the system into which they 

discharge. This information will also allow the permittee to prioritize inspections and tailor 

education and outreach efforts, which will best assist the facility in implementing appropriate 

pollution prevention practices or other on-site stormwater controls. In addition, the inventory 

data will allow the permittee to determine whether the facilities may discharge pollutants of 

concern into impaired waters. Finally, the information contained in the inventory will enable 

permittees to characterize these facilities and prioritize them based on their potential impact on 

stormwater quality. By prioritizing facilities in such a manner, the permittee may then establish 

a targeted approach towards conducting inspections (see Part 7.3 for a discussion of inspection 

frequency). 

In addition, data from NPDES pretreatment programs within the MS4 boundary on significant 

industrial users (SIUs) could also be used to identify and prioritize the industrial sites in the 

stormwater program. 

 

26San Diego MS4 Permit (www.swrcb.ca.gov/rwqcb9/water_issues/programs/stormwater/docs/sd_permit/

r9_2007_0001/2007_0001final.pdf), with modifications. 

Chapter 7: Industrial Stormwater Sources 87
MS4 Permit Improvement Guide 

Recommendations for the Permit Writer 

The example permit provision lists specific commercial and industrial sources to be included in the 

inventory, but permit writers should customize this list to meet specific issues in their area. For 

example, some permittees may have large industrial areas with few commercial businesses, while 

others may have a large number of restaurants and retail businesses but no industrial facilities at all. 

Other permittees may have had past water quality problems at certain types of commercial or 

industrial sites, in which case such facilities should be included in their inventories. 

7.2 Industrial Facility Stormwater Control Measures 

Example Permit Provision 

7.2.1 The permittee must require industrial and commercial facilities included in the Part 

7.1 inventory to select, install, implement, and maintain stormwater control 

measures. At a minimum, these control measures must: 

a. Minimize Exposure – Industrial/commercial facilities must minimize the 

exposure of manufacturing, processing, and material storage areas (including 

loading and unloading, storage, disposal, cleaning, maintenance, and fueling 

operations) to rain, snow, snowmelt, and runoff by either locating these 

industrial materials and activities inside or protecting them with storm resistant 

coverings (although significant enlargement of impervious surface area is not 

recommended). The facilities must consider, where appropriate: 

1. Using grading, berming, or curbing to prevent runoff of contaminated flows 

and divert run-on away from these areas 

2. Locating materials, equipment, and activities so that leaks are contained in 

existing containment and diversion systems (confine the storage of leaky or 

leak-prone vehicles and equipment awaiting maintenance to protected 

areas) 

3. Cleaning up spills and leaks promptly using dry methods (e.g., absorbents) to 

prevent the discharge of pollutants 

4. Using drip pans and absorbents under or around leaky vehicles and 

equipment or store indoors where feasible 

5. Using spill/overflow protection equipment 

6. Draining fluids from equipment and vehicles prior to on-site storage or 

disposal 

7. Performing all cleaning operations indoors, under cover, or in bermed areas 

that prevent runoff and run-on and also that capture any overspray 

8. Ensuring that all wash water drains to a proper collection system (i.e., not 

the stormwater drainage system) 

b. Follow Good Housekeeping Practices – Industrial/commercial facilities must 

keep clean all exposed areas that are potential sources of pollutants, using such 

Chapter 7: Industrial Stormwater Sources 88
MS4 Permit Improvement Guide 

measures as sweeping at regular intervals, keeping materials orderly and 

labeled, and storing materials in appropriate containers. 

c. Conduct Maintenance – Industrial/commercial facilities must regularly inspect, 

test, maintain, and repair all industrial equipment and systems to avoid 

situations that may result in leaks, spills, and other releases of pollutants in 

stormwater discharged to receiving waters. 

d. Implement Spill Prevention and Response Procedures – Industrial/commercial 

facilities must minimize the potential for leaks, spills and other releases that may 

be exposed to stormwater and develop plans for effective response to such spills 

if or when they occur. At a minimum, the facilities must implement: 

1. Procedures for plainly labeling containers (e.g., “Used Oil,” “Spent Solvents,” 

“Fertilizers and Pesticides,”) that could be susceptible to spillage or leakage 

to encourage proper handling and facilitate rapid response if spills or leaks 

occur 

2. Preventative measures such as barriers between material storage and traffic 

areas, secondary containment provisions, and procedures for material 

storage and handling 

3. Procedures for expeditiously stopping, containing, and cleaning up leaks, 

spills, and other releases. Employees who may cause, detect, or respond to a 

spill or leak must be trained in these procedures and have necessary spill 

response equipment available. 

4. Procedures for notification of appropriate facility personnel, emergency 

response agencies, and regulatory agencies [Insert appropriate contacts for 

reporting] 

e. Implement Erosion and Sediment Controls – Industrial/commercial facilities 

must stabilize exposed areas and contain runoff using structural and/or nonstructural control measures to minimize onsite erosion and sedimentation, and 

the resulting discharge of pollutants. 

f. Manage Runoff – Industrial/commercial facilities must divert, infiltrate, reuse, 

contain, or otherwise reduce stormwater runoff, to minimize pollutants in 

discharges. 

g. Address Salt Storage Piles or Piles Containing Salt – Industrial/commercial 

facilities must enclose or cover storage piles of salt, or piles containing salt, used 

for deicing or other commercial or industrial purposes, including maintenance of 

paved surfaces. If a permanent storage structure is required but does not exist, 

one must be built within [insert timeframe], and seasonal tarping must be used 

as an interim control until the permanent structure is completed. Facilities must 

implement appropriate measures (e.g., good housekeeping, diversions, 

containment) to minimize exposure resulting from adding to or removing 

materials from the pile. Piles do not need to be enclosed or covered if 

stormwater runoff from the piles is not discharged or if discharges from the piles 

are authorized under another NPDES permit. 

h. Conduct Employee Training – All facility employees who work in areas where 

industrial materials or activities are exposed to stormwater, or who are 

Chapter 7: Industrial Stormwater Sources 89
MS4 Permit Improvement Guide 

responsible for implementing activities necessary to manage stormwater must 

be trained. Training must be conducted [insert frequency, e.g. at least annually]. 

i. Address Non-Stormwater Discharges – Industrial/commercial facilities must 

eliminate non-stormwater discharges not authorized by an applicable NPDES 

permit. 

j. Control Waste, Garbage and Floatable Debris – Facilities must ensure that waste, 

garbage, and floatable debris are not discharged to receiving waters by keeping 

exposed areas free of such materials or by intercepting them before they are 

discharged. 

k. Control Dust Generation and Vehicle Tracking of Industrial Materials – 

Industrial/commercial facilities must minimize generation of dust and off-site 

tracking of raw, final, or waste materials.27

7.2.2 Within the [insert deadline, e.g. first two years of permit term], the permittee must 

notify the owner/operator of each industrial and commercial site/source of the 

stormwater requirements for control measures in Part 7.2.1. 

7.2.3 As necessary to minimize any pollutants causing the applicable receiving waterbody 

to be listed as impaired, the permittee must require implementation of additional 

controls for industrial and commercial sites/sources that are tributary to the 

impaired water body segments and that are likely to generate such impairment 

pollutants.28

Example Permit Requirement Rationale for the Fact Sheet 

The permittee is required to ensure that the minimum control measures are implemented, as 

applicable, at every industrial/commercial facility included in its inventory. The minimum 

measures outlined, when properly selected, designed and implemented, promote prevention 

and source control, before treatment. 

The control measures in this permit are consistent with the control measure requirements 

found in EPA’s 2008 Multi-Sector General Permit (MSGP) for stormwater discharges from 

industrial activities. The permit writer should ensure that these requirements are consistent 

with the State’s industrial stormwater permit. The control measures in this permit describe 

specific activities that the permittee must require industrial facilities and commercial sites to 

implement to minimize stormwater pollution. Another control measure is simply preventing 

pollutants from coming into contact with precipitation in the first place since this will ensure 

they are not carried into nearby waterways. General good housekeeping and maintenance 

procedures are also required. Additional control measures address spill prevention and 

response, erosion and sediment controls, managing runoff, and controlling discharges from salt 

storage piles. 

 

27 2008 MSGP (Section 2) (www.epa.gov/npdes/pubs/msgp2008_finalpermit.pdf), with modifications 28 San Diego MS4 Permit (www.swrcb.ca.gov/rwqcb9/water_issues/programs/stormwater/docs/sd_permit/

r9_2007_0001/2007_0001final.pdf), with modifications 

Chapter 7: Industrial Stormwater Sources 90
MS4 Permit Improvement Guide 

The control measures must also include employee training, controlling non-stormwater 

discharges, addressing waste, garbage and floatable debris, and addressing dust generation and 

vehicle tracking.29

The permittee is required to notify industrial and commercial sites of the control measure 

requirements and their responsibility to implement and comply with the requirements. 

Facilities that discharge into impaired waterbodies may be required to implement additional 

controls as necessary to prevent the discharge of the associated pollutants of concern. 

7.3 Industrial and Commercial Facility Inspections 

Example Permit Provision 

7.3.1 Industrial and Commercial Site Inspection Program 

a. The permittee must continue to implement a program to inspect all commercial 

and industrial facilities included in its Part 7.1(a) inventory. The permittee must 

describe how this will occur in the SWMP. 

b. The inspection program must: 

1. Prioritize all facilities into high, medium, and low categories on the basis of 

the potential for water quality impact using criteria such as pollutant sources 

on site, pollutants of concern, proximity to a water body, and violation 

history of the facility. The different priority categories will be assigned 

different inspection frequencies, with the highest priority facilities receiving 

more frequent inspections. Describe the process for prioritizing inspections 

and frequency of inspections. If any geographical areas are to be targeted 

for inspections due to high potential for stormwater pollution, these areas 

must be listed in the Inspection Plan. 

3. Explain how the priority assigned to any one facility may be modified based 

on the site inspection findings and the facility’s potential to discharge 

pollutants. 

7.3.2 Minimum Inspection Requirements 

a. Inspection Frequency – The permittee is required to conduct inspections at the 

following frequencies, at a minimum: 

1. Facilities with high potential for water quality impact must be inspected 

[insert frequency, e.g. annually]. 

2. Facilities with medium potential for water quality impact must be inspected 

at least [insert frequency, e.g. once every three years]. 

3. Facilities with low potential for water quality impact must be inspected at 

least [insert frequency, e.g. once every 5 years]. 

 

29 2008 MSGP Fact Sheet (www.epa.gov/npdes/pubs/msgp2008_finalfs.pdf), with modifications 

Chapter 7: Industrial Stormwater Sources 91
MS4 Permit Improvement Guide 

4. Facilities with either a [insert violation type] written violation occurring in 

the previous year must be inspected at least [insert frequency, e.g. annually] 

until compliance is achieved. 

5. For facilities with no exposure of commercial or industrial activities to 

stormwater, no inspections are required. However, the permittee must 

continue to track these facilities for significant change in the exposure of 

their operations to stormwater. 

b. Scope of Inspection – Inspections must at a minimum: 

1. Evaluate the facility’s compliance with the Part 7.2 requirement to select, 

design, install, and implement stormwater control measures. 

2. Conduct a visual observation for evidence of unauthorized discharges, illicit 

connections, and potential discharge of pollutants to stormwater. 

3. Verify whether the facility is required to be authorized under the [insert 

applicable NPDES general industrial stormwater permit], and whether the 

facility has in fact obtained such permit coverage.30

4. Evaluate the facility’s compliance with any other relevant local stormwater 

requirements. 

c. Documentation Requirements – At a minimum, the permittee must document 

the following for each inspection: 

The inspection date and time; 

The name(s) and signature(s) of the inspector(s); 

1. Weather information and a description of any discharges occurring at the 

time of the inspection; 

2. Any previously unidentified discharges of pollutants from the site; 

3. Any control measures needing maintenance or repairs; 

4. Any failed control measures that need replacement; 

5. Any incidents of noncompliance observed; and 

6. Any additional control measures needed to comply with the Permit 

Requirements. 

d. Track Inspections – Inspection findings must be tracked to ensure inspections 

are conducted at the frequency specified in Part 7.3.2.b., highlight and 

document the recidivism of noncompliant facilities, and aid follow up and 

enforcement activities. 

7.3.3 Enforcement – The permittee must ensure that all necessary follow up and 

enforcement activities are conducted as necessary to require necessary 

implementation and maintenance of the control measures described in Part 7.2. 

The permittee is required to utilize the approved ERP for all enforcement actions. 

 

30 San Francisco Bay Region Municipal Regional Stormwater NPDES Permit 

(www.swrcb.ca.gov/sanfranciscobay/board_decisions/adopted_orders/2009/R2-2009-0074.pdf), with 

modifications 

Chapter 7: Industrial Stormwater Sources 92
MS4 Permit Improvement Guide 

Example Permit Requirement Rationale for the Fact Sheet 

The permittee must design an inspection program that facilitates more frequent inspections of 

the highest priority facilities. (See 40 CFR 122.26(d)(iv)(C)(1)). This will help maximize use of the 

permittee’s existing inspection resources and ensure that the permittee inspectors are the most 

visible and the most familiar with the facilities with the highest potential for water quality 

impact. 

The permittee must develop a process for prioritizing inspections and designating all facilities in 

the industrial and commercial inventory as either a high, medium or low priority. The 

designation could occur by individual facility or by facility type. The prioritization for individual 

facilities may be adjusted after the first, or any subsequent, inspection (for example, if a facility 

is a high priority facility and the inspection reveals it has little potential for stormwater 

pollution, then the facility could be reprioritized as a low priority facility). 

It is important that inspections be conducted in a thorough and consistent manner in 

accordance with a formal protocol for conducting an inspection. This protocol should be the 

basis for inspector training as well. Inspections should include a thorough walk-through of the 

facility. 

The documentation of inspections is very important, not only when tracking noncompliance, but 

also to facilitate effective enforcement action when needed. A timeline of noncompliance and 

subsequent enforcement action is critical when escalating measures to gain compliance. 

Typically, the use of inspection forms facilitates complete and consistent documentation among 

inspectors and over time. 

Recommendations for the Permit Writer 

The permit writer may choose to define what criteria the permittee will use to determine the 

priority of each facility on its inventory. For example, the Phase I Los Angeles County MS4 permit 

specifies which facilities are Tier 1 and Tier 2 and provides the required inspection frequency for 

each. The permit writer could also automatically designate certain sets of industries to a certain 

priority category (e.g., all facilities subject to the State’s Industrial General Permit could be 

designated as high priority facilities in the permit). If the permit does not define what criteria are to 

be used when prioritizing facilities, the permittee should be required to develop this protocol and 

submit it to the permitting authority for review. 

The permit writer should review available industrial and commercial inventories to determine if 

more specific inspection frequencies should be set. For example, an MS4 with only 10 facilities in 

the inventory could probably inspect those facilities annually. However, an MS4 with over 2,000 

facilities in the inventory may need to set the inspection frequency at a less frequent interval. 

Chapter 7: Industrial Stormwater Sources 93
MS4 Permit Improvement Guide 

Chapter 7: Industrial Stormwater Sources 94

7.4 Staff Training 

Example Permit Provision 

7.4.1 The permittee must ensure that all staff whose primary job duties are implementing 

the industrial stormwater program is trained to conduct facility inspections. The 

training must cover what is required under this permit in terms of stormwater 

control measures, the requirements of other applicable Industrial Stormwater 

general permits or other related local requirements, the permittee’s site inspection 

and documentation protocols, and enforcement procedures. Follow-up training 

must be provided every other year to address changes in procedures, techniques, or 

staffing. Permittees must document and maintain records of the training provided 

and the staff trained.31

Example Permit Requirement Rationale for the Fact Sheet 

Inspectors responsible for conducting inspections at industrial/commercial facilities must be 

trained on the applicable stormwater requirements for the different types of facilities (i.e., 

industrial, commercial, other). Training must include a summary of federal, state, and local 

stormwater regulations that may apply to industrial/commercial facilities. Inspectors must be 

familiar with various types of stormwater control measures commonly used at the types of 

facilities typically found in the MS4 area and must be able to educate facility operators about 

such stormwater control measures. In addition, inspectors must understand and use the 

permittee’s established enforcement response plan (see Chapter 1 of this Guide) to gain 

compliance as necessary. The inspection staff must be proficient in the enforcement escalation 

procedure and must properly document all enforcement actions accordingly per the ERP. 

 

31 Western Washington Phase I MS4 Permit (www.ecy.wa.gov/programs/wq/stormwater/municipal/phaseIpermit/

MODIFIEDpermitDOCS/PhaseIpermitSIGNED.pdf), with modifications 
CHAPTER 8: MONITORING, EVALUATION, AND REPORTING

Introduction 

Phase I MS4s are required to conduct discharge characterization, 

field screening and develop a monitoring program. Phase I MS4s are 

also required to conduct an assessment of controls. See 40 CFR 

122.26(d)(1)(iii), (d)(2)(iii), and (d)(2)(v). 

Phase II MS4 regulations allow, but do not specifically require, 

monitoring. Phase II MS4s are required to evaluate program 

compliance, the appropriateness of identified control measures, 

and progress toward achieving identified measurable goals. See 40 

CFR 122.34(g). 

There are many components involved in monitoring and evaluating 

the effectiveness of a municipal stormwater program. Any 

comprehensive monitoring program should have clear monitoring 

objectives to help determine compliance and water quality impacts. 

Each monitoring program is unique and should be customized to the specific waterbodies, impairments, 

and pollutant sources of the MS4. 

Included Concepts

► Consolidated information 

tracking system 

► Development of a 

comprehensive 

monitoring and 

assessment program 

► Evaluation of overall 

program effectiveness 

► Requirements for annual 

reporting of MS4 activities 

Evaluating the overall effectiveness of the municipal stormwater program should be done using 

information from the monitoring program, progress toward meeting measurable goals, and other 

indicators. Without assessing the effectiveness of the stormwater management program the permittee 

will not know which parts of the program need to be modified to protect and/or improve water quality 

and instead will essentially be operating blindly. Establishing a comprehensive monitoring and 

assessment program will enable the permittee to track progress in complying with permit provisions and 

implementing a program to protect water quality. 

8.1 Consolidated Information Tracking System 

Example Permit Provision 

8.1.1 Within the first [insert time frame which corresponds to the development of the 

monitoring program e.g. first two years of permit], the permittee must develop a 

tracking system to track the information required in the permit as well as the 

information required to be reported in the annual report (see Part 8.4). 

Chapter 8: Monitoring, Evaluation, and Reporting 95 
MS4 Permit Improvement Guide 

Example Permit Requirement Rationale for the Fact Sheet 

An important part of any municipal stormwater program is to document and track information 

on activities the permittee undertakes to comply with the Permit Requirements. Tracking 

should be integrated into each of the minimum measures. For example, tracking the location of 

illicit discharges may indicate that a specific area has a high incidence of motor oil being 

dumped into storm drains. Investigations may reveal that homeowners are changing the motor 

oil in their cars, but not properly disposing it. Therefore, the permittee will need to educate the 

homeowners in that area regarding proper disposal. 

The permittee must develop a tracking system to monitor implementation of its various 

programs in order to document the permittee’s compliance with its Permit Requirements, such 

as the number of construction sites and industrial facilities inspected. In addition, the tracking 

system will allow the permitee to monitor the compliance status of those entities within its 

jurisdiction, such as construction sites and industrial facilities, and to ensure compliance of 

municipally-owned and operated facilities. 

Any tracking system should be coordinated with the monitoring and evaluation programs 

developed by the permittee. Ideally, a monitoring and evaluation program will link the 

“actions” (e.g., the inspections, maintenance, education and other activities the permittee 

implements) with the “results” (e.g., water quality monitoring data, improvements in 

environmental indicators) of the monitoring program. 

In addition, adequate tracking is necessary to generate and provide reports of program progress 

not only to the permitting authority, but to a permittee’s internal management for planning and 

funding purposes. Ideally, a MS4 permittee will have at least one person in charge of overall 

coordination, including tracking. While many departments or agencies might implement various 

stormwater program components, it is helpful for a single person or department to gather and 

analyze applicable data. This can be accomplished in a number of ways and will vary based on 

existing data tracking mechanisms used by a permittee, the data being captured and the reporting 

requirements the permittee must comply with. Ideally, the program would have a database 

accessible by all parties which specifies the required data. Lacking this, the permittee will need to 

coordinate all responsible parties. The permittee will need to ensure that responsible parties 

“mine” all data necessary to adequately represent the program and permit compliance, and 

specify adequate internal reporting deadlines to guarantee that the data is available in a timely 

manner for program planning, effectiveness assessments and permit reporting. Some permittees 

create reporting forms for program component managers to complete and submit by internal 

deadlines. Regardless of how the permittee coordinates the effort internally, without adequate 

tracking of data the permittees will not be able to submit annual reports to the permitting 

authority that provide the necessary information to determine permit compliance. 

Recommendations for the Permit Writer 

To assist the permittee in ensuring appropriate data is gathered and analyzed, the permitting 

authority should be very clear regarding annual reporting requirements. In addition, the text for this 

section should be tailored depending on the permittee. For example, some permittees may be able 

to develop a GIS-based system complete with the option to upload pictures and inspection reports 

versus a spreadsheet. In the text provided either system would meet the requirements, but more 

detailed information can be obtained with the GIS-based system. 

Chapter 8: Monitoring, Evaluation, and Reporting 96
MS4 Permit Improvement Guide 

8.2 Development of a Comprehensive Monitoring & Assessment 

Program 

Example Permit Provision 

8.2.1 The permittee must continue to implement, and revise as necessary, a 

comprehensive monitoring and assessment program. A description of this program 

must be included in the SWMP document. The monitoring and assessment program 

must be designed to meet the following objectives: 

a. Assess compliance with this permit; 

b. Measure the effectiveness of the permittee’s stormwater management 

program; 

c. Assess the chemical, physical, and biological impacts to receiving waters 

resulting from stormwater discharges; 

d. Characterize stormwater discharges; 

e. Identify sources of specific pollutants; 

f. Detect and eliminate illicit discharges and illegal connections to the MS4; and 

g. Assess the overall health and evaluate long-term trends in receiving water 

quality. 

NOTE: Because monitoring programs and requirements are very specific to the MS4 and 

local water quality impairments, permit writers are directed to the “Recommendations to 

the Permit Writer” section below for examples of comprehensive monitoring program 

Permit Requirements. 

Example Permit Requirement Rationale for the Fact Sheet 

Without clear monitoring objectives and a detailed monitoring plan, it will be difficult for 

permittees and permitting authorities to evaluate the effectiveness of the municipal stormwater 

program. 

There are numerous factors that should be examined while setting up the water quality 

monitoring portion of the comprehensive program. Understanding and considering climatic 

conditions such as precipitation patterns, temperature, and seasonal variations will ensure the 

study design will collect data that are representative of typical storms in the area and that 

sampling occurs during times of the year when it is most logical to do so. Acknowledging the 

different types of land uses within the area will also help the permittee to prioritize monitoring 

efforts based on the areas most likely to be impacted by stormwater. The type of waterbody 

monitored must also be considered when selecting sampling locations since pollutants behave 

differently depending on the environment thereby impacting sampling protocols. For example, 

sampling in a freshwater lake involves different protocols than monitoring in a tidally influenced 

river or a first order stream. Waterbody type can also influence the data results and conclusions 

(e.g. freshwater wetlands typically have high denitrification rates that will likely impact the 

results of nitrate sampling). 

Chapter 8: Monitoring, Evaluation, and Reporting 97
MS4 Permit Improvement Guide 

Selection of specific sampling locations is also very important. If particular sites are of concern, 

then monitoring both above and below the sites to figure out their contributions to the overall 

water quality issues may make sense. Also, the actual location in the waterbody is important to 

specify for consistency. For example, should samples be taken close to the stream bank or in 

the center of the waterbody, in riffles or pools? The answers to these questions, of course, 

depend on the goals of the monitoring and the constituents (biological, chemical, hydrological) 

being examined. 

In addition, the number and frequency of samples collected and stream assessments performed 

will determine how robust the data will be (see page 287 in National Research Council’s Report 

Urban Stormwater Management in the United States (2009) available at 

www.epa.gov/npdes/pubs/nrc_stormwaterreport.pdf). Monitoring may or may not be tied to 

specific wet weather events (i.e. within 72 hours after a rainfall event). A combination of 

specific wet weather samples and dry weather samples may be appropriate. 

Establishing objectives with associated indicators (environmental or administrative) for each 

minimum measure can help put each component into perspective when considering the overall 

program. Indicators are one way to evaluate the success of the program from the overall 

program level. Developing standard environmental indicators is a critical step to evaluate the 

SWMP. Permittees need practical tools, such as these indicators, in order to determine if their 

stormwater programs are working, and that help elucidate where additional efforts may be 

most critical. Environmental indicators should be selected based on the type 

(estuarine/freshwater/brackish) and condition (impaired/non-impaired) of the waterbody to 

which stormwater is discharged as well as the intended use of the area where the stormwater is 

discharged (source water protection area, etc.). 

In addition, permittees should document certain administrative efforts associated with 

developing and implementing their SWMPs. In this context ‘administrative’ is considered quite 

broad, including such things as control measures, inspection programs, policies and rules, MS4 

system scope and condition, educational efforts and any other variable or outcome that could 

reflect on the quality of a stormwater program other than the actual environmental quality 

outcomes, which are covered under ‘Environmental Indicators’. 

Good administrative indicators are numerous, and good suites of indicators will vary from one 

community to another. More information can be obtained on each of the environmental and 

administrative indicators listed by going to the Stormwater Manager’s Resource Center 

(www.stormwatercenter.net) and selecting “Monitor/Assess” on the left navigation bar. 

Several protocols have been developed to assess the effectiveness of stormwater control 

measures: 

 Guidance for Evaluating Emerging Stormwater Treatment Technologies, Technology 

Assessment Protocol - Ecology (TAPE) www.ecy.wa.gov/biblio/0210037.html . This 

guidance document′s primary purpose is to establish a testing protocol and process for 

evaluating and reporting on the performance and appropriate uses of emerging 

stormwater treatment technologies. 

 Technology Acceptance Reciprocity Partnership (TARP) Protocol for Stormwater Best 

Management Practice Demonstrations www.dep.state.pa.us/dep/deputate/

pollprev/techservices/tarp/pdffiles/Tier2protocol.pdf . The purpose of the TARP 

Chapter 8: Monitoring, Evaluation, and Reporting 98
MS4 Permit Improvement Guide 

Protocol is to provide a uniform method for demonstrating stormwater technologies 

and developing test quality assurance (QA) plans for certification or verification of 

performance claims. 

 BMP Performance Verification Checklist. This is a tool that helps permittees provide a 

consistent set of questions for applicants proposing to use manufactured and 

proprietary BMP. It is available as Tool # 8 of the Center for Watershed Protection’s 

Managing Stormwater in Your Community. The checklist is accompanied by an 

explanation and instructions for using the checklist, technical appendices, and a matrix 

that compares existing verification protocols, such as TARP and TAPE. 

Additional monitoring resources include: 

 CWP, 2008, Monitoring to Demonstrate Environmental Results: Guidance to Develop 

Local Stormwater Monitoring Studies Using Six Example Study Designs (www.cwp.org) 

 Geosyntec Consultants and Wright Water Engineers, 2009, Urban Stormwater BMP 

Performance Monitoring, (bmpdatabase.org/MonitoringEval.htm) 

 CASQA, 2007, Municipal Stormwater Program Effectiveness Assessment Guidance

(www.casqa.org) 

Recommendations for the Permit Writer 

Because of the site-specific nature and variability of these monitoring programs between 

permittees, the detailed requirements should be provided by each permit writer. For example, the 

Phase I regulations included specific monitoring requirements while the Phase II regulations allow, 

but do not specifically require monitoring. To assist permit writers, several examples of monitoring 

requirements from existing MS4 permits are listed below: 

 Baltimore County, MD Phase I MS4 permit (issued 2005); see the watershed assessment and 

planning requirements (Part II.F) and assessment of controls (Part II.H) 

www.mde.state.md.us/assets/document/sedimentStormwater/MSSPermit/BA%20final%20

permit.pdf

 Southern California Regional Bioassessment Monitoring Program (this is a regional monitoring 

program involving coastal counties in Southern California) 

www.socalsmc.org/Docs/SMC-DesignofBioassessmentRegionalMonitoringProgram.pdf

 San Diego, CA Phase I MS4 Permit (issued 2007); see Receiving Waters and Urban Runoff 

Monitoring and Reporting Program. 

www.waterboards.ca.gov/sandiego/water_issues/programs/stormwater/docs/sd_permit/

r9_2007_0001/2007_0001final.pdf

The permit writer could consider the role of partnerships among the MS4s in establishing and 

implementing the monitoring programs so that any data collected is robust, useful, and meaningful. 

In addition, communities may benefit more by working with local organizations and/or neighboring 

communities who are already collecting similar data. By doing so resources may be used more 

efficiently and results of testing may be more robust. 

Chapter 8: Monitoring, Evaluation, and Reporting 99
MS4 Permit Improvement Guide 

The permit writer should also require the permittee to assess the effectiveness of the SWMP in 

meeting applicable Permit Requirements. The sampling protocols developed must support the goals 

of the monitoring program. The monitoring and assessment program must include water quality 

monitoring as well as an assessment of environmental and administrative indicators. Along these 

lines, the permit writer could also add requirements such as the ones provided below: 

Water Quality Monitoring

a. The Permittee must develop a water quality monitoring program that includes [insert 

specific monitoring programs and requirements, such as: 

 Ambient receiving water monitoring, 

 Biological monitoring, 

 Control measure performance monitoring, or 

 Discharge (wet weather) monitoring 

Because the detailed monitoring program requirements are very unique to each MS4, 

the permitting authority should insert here the specific details of the relevant 

monitoring program, such as monitoring type, frequency, location, etc.] 

b. When determining water quality monitoring components, the permittee must 

examine and consider a variety of factors, including, but not limited to: 

 Climatic conditions, including precipitation patterns, temperature, and seasonal 

variations 

 Land uses in the MS4 

 Waterbody type 

c. The permittee must consider and address specific sampling quality assurance/quality 

control protocols, including, but not limited to: 

 Specific chemical constituents (pollutants), biological stream indicators, and physical 

stream indicators that will be monitored to best achieve the purpose of the monitoring 

 Sampling locations 

 Number and frequency of sample collection and assessments 

 Timing of sample collection 

d. The permittee must determine if any similar monitoring is occurring within the MS4 

and if it is logical to link efforts. 

Environmental Indicators

 As part of the comprehensive monitoring and assessment program, the permittee must 

identify and track at least [insert number of indicators to be tracked] environmental 

Chapter 8: Monitoring, Evaluation, and Reporting 100
MS4 Permit Improvement Guide 

indicators from each category listed below (physical and hydrologic indicators; biological 

indicators; water quality indicators). The indicators must be appropriate to assess if the 

SWMP is meeting goals and objectives: 

Physical and hydrological 

indicators

 Stream widening/ 

downcutting 

 Physical habitat quality 

 Impacted dry weather 

flows 

 Increased flooding 

frequency 

 Stream temperature 

monitoring 

Biological indicators

 Fish assemblage 

analysis 

 Macro-invertebrate 

assemblage 

 Single species 

indicator 

 Composite indicators 

 Other biological 

indicators 

Water quality indicators

 Water quality pollutant 

constituent monitoring 

 Toxicity testing 

 Non-point source 

loadings 

 Exceedance frequencies 

of water quality 

standards 

 Sediment contamination 

 Human health criteria 

Administrative indicators

As part of the comprehensive monitoring and assessment program, the permittee must identify 

and track at least [insert number of indicators to be tracked] administrative indicator from each 

category listed below (social indicators; programmatic indicators; site indicators). The indicators 

must be appropriate to assess if the SWMP is meeting goals and objectives: 

Social indicators

 Public attitude surveys 

 Industrial/commercial 

pollution prevention 

 Public involvement and 

monitoring 

 User perception 

Programmatic indicators

 Number of illicit 

connections identified 

and corrected 

 Number of control 

measures installed, 

inspected, and 

maintained 

 Permitting and 

compliance 

 Growth and 

development 

Site indicators

 Control measure 

performance 

monitoring 

 Industrial site 

compliance monitoring 

Performance Monitoring of Stormwater Controls

When monitoring the performance of stormwater controls, EPA recommends that percent 

removal efficiencies are not calculated and compared since results can be misleading because 

the percentages may be based on differing levels of the influent concentration (see 

cfpub.epa.gov/npdes/stormwater/urbanbmp/bmptopic.cfm#percentremoval for further 

discussion; also see National Research Council’s Report Urban Stormwater Management in the 

United States (2009) available at www.epa.gov/npdes/pubs/nrc_stormwaterreport.pdf). 

Modeling can also be a useful tool to quantify the impacts of municipal stormwater management. 

The following resources provide summaries and reviews of different types of models available to 

Chapter 8: Monitoring, Evaluation, and Reporting 101
MS4 Permit Improvement Guide 

determine existing loading from an MS4 as well as the effects expected from various stormwater 

controls. 

1. USEPA Handbook for Developing Watershed Plans to Restore and Protect Our Waters 

www.epa.gov/nps/watershed_handbook/

Chapter 8 of this document focuses on methods for estimating pollutant loads, including the use 

of watershed models. This chapter provides assistance in selecting and applying watershed 

models to estimate pollutant loads from existing conditions. 

2. USEPA TMDL Model Evaluation and Research Needs 

www.epa.gov/nrmrl/pubs/600r05149/600r05149.htm

This report documents the review of more than 60 available watershed and receiving water 

models. It discusses model selection on the basis of model capabilities and provides a series 

of tables rating the capabilities or applicability the models using the categories of TMDL 

endpoints, general land and water features, special land processes, special water processes, 

and application considerations including the selection of appropriate best management 

practices and their water quality impacts. The document also provides individual fact sheets 

for each reviewed model. 

8.3 Evaluation of Overall Program Effectiveness 

Example Permit Provision 

8.3.1 Annual Effectiveness Assessment – The annual effectiveness assessment must: 

a. Use the monitoring and assessment data described in Part 8.2 to specifically 

assess the effectiveness of each of the following: 

1. Each significant activity/control measures or type of activity/control 

measure implemented; 

2. Implementation of each major component of the Stormwater Management 

Program (Public Education/Involvement, Illicit Discharges, Construction, 

Post-Construction, Good Housekeeping); and 

3. Implementation of the Stormwater Management Program as a whole. 

b. Identify and use measurable goals, assessment indicators, and assessment 

methods for each of the items listed in Part 8.3.1.a above. 

c. Document the permittee’s compliance with permit conditions. 

8.3.2 Based on the results of the effectiveness assessment, the permittee must annually 

review its activities or control measures to identify modifications and improvements 

needed to maximize SWMP effectiveness, as necessary to achieve compliance with 

this permit. The permittee must develop and implement a plan and schedule to 

address the identified modifications and improvements. Municipal activities/control 

Chapter 8: Monitoring, Evaluation, and Reporting 102
MS4 Permit Improvement Guide 

measures that are ineffective or less effective than other comparable municipal 

activities/control measures must be replaced or improved upon by implementation 

of more effective municipal activities/control measures. 

8.3.3 As part of its Annual Reports, the permittee must report on its SWMP effectiveness 

assessment as implemented under Part 8.3.1 above. 

Example Permit Requirement Rationale for the Fact Sheet 

A key requirement in the stormwater Phase II rule is a report (40 CFR 122.34(g)(3)) that includes 

“the status of compliance with permit conditions, an assessment of the appropriateness of 

identified [control measures] and progress towards achieving identified measurable goals for 

each of the minimum control measures.” This assessment is critical to the stormwater program 

framework which uses the iterative approach of implementing controls, conducting 

assessments, and designating refocused controls leading toward attainment of water quality 

standards. 

Building on the monitoring and assessment program developed in Part 8.2, the permittee must 

conduct an annual effectiveness assessment to assess the effectiveness of significant control 

measures, SWMP components, and the SWMP as a whole. The California Stormwater Quality 

Association’s (CASQA) Municipal Stormwater Program Effectiveness Guidance describes 

strategies and methods for assessing effectiveness, including examples of effectiveness 

assessment for each SWMP program component. The CASQA Effectiveness Guidance is available 

at www.casqa.org for purchase. A two-hour EPA webcast focusing on the CASQA Guide is also 

available (available at www.epa.gov/npdes/training under “Assessing the Effectiveness of Your 

Municipal Stormwater Program”). A resources document from the webcast includes a 10 page 

summary of the Guide and example pages from the municipal chapter 

(www.epa.gov/npdes/outreach_files/webcast/jun0408/110961/municipal_resources.pdf). 

The Municipal Stormwater Program Effectiveness Assessment Guidance synthesizes information 

on designing and conducting program effectiveness assessments. The document also explains 

how to select certain methods based on programmatic outcomes and goals. The reader is led 

through a series of questions and case studies to demonstrate how proper assessments are 

selected. Techniques are related to different level of outcomes: level one – documenting 

activities, level two – raising awareness, level 3 – changing behavior, level 4 – reducing loads 

from sources, level 5 – improving runoff quality, and level 6 – protecting receiving water quality. 

The Guide includes fact sheets for all six NPDES program elements, outlining methods and 

techniques for assessing effectiveness of each program. 

Recommendations for the Permit Writer 

Adaptive management is the appropriate process for assessing new opportunities for improving 

program effectiveness in controlling stormwater pollution. The permit writer should require the 

permittee to use adaptive management throughout the permit term to assess options for improving 

controls on stormwater discharges as compared with measurable goals and demonstrated by 

monitoring and assessment protocols. The permit writer should have the permittee monitor and 

Chapter 8: Monitoring, Evaluation, and Reporting 103
MS4 Permit Improvement Guide 

assess the data and analyses required under the permit as well as applicable information from other 

sources in the adaptive management process. 

In addition, the permit writer should have the permittee assess and modify, as necessary, any or all 

existing SWMP components and adopt new or revised SWMP components to optimize reductions in 

stormwater pollutants through an iterative process. This iterative process should include routine 

assessment of the need to further improve water quality and protect beneficial uses, review of 

available technologies and practices to accomplish the needed improvement, and evaluate 

resources available to implement the technologies and practices. 

8.4 Requirements for Annual Reporting of MS4 Activities 

Example Permit Provision 

8.4.1 Summary Annual Report - The Permittee must submit annual reports on or before 

[specify deadline, e.g., the anniversary date of this permit] for the reporting period 

[specify the reporting period, e.g., July 1-June 30]. The Permittee must use the 

Summary MS4 Annual Report template in Appendix A to document a summary of 

the past year activities. All of the information required on this form must be 

completed. 

8.4.2 Detailed Annual Report - The Permittee must also submit a detailed annual report 

that addresses, for the activities described in the SWMP document required in Part 

1.1, the following: 

 A summary of past year activities, including where available, specific quantities 

achieved and summaries of enforcement actions. See Part 8.4.3 for required 

information specific to certain SWMP areas. 

 A description of the effectiveness of each SWMP program component or activity 

(see Part 8.3); and 

 Planned activities and changes for the next reporting period, for each SWMP 

program component or activity. 

 Detailed fiscal analysis described in Part1.4.2. 

8.4.3 [Specify any additional information and/or data pertaining to implementation of 

priority activities the Permitting Authority would like to see in Annual Reports, e.g. a 

list of green roofs (with square footage) installed in the MS4, a summary of water 

quality monitoring data collected for a specific waterbody, etc.] 

The Annual Report must clearly refer to the Permit Requirements, and describe in 

quantifiable terms, the status of activities undertaken to comply with each 

requirement. 

Chapter 8: Monitoring, Evaluation, and Reporting 104
MS4 Permit Improvement Guide 

Example Permit Requirement Rationale for the Fact Sheet 

In general, an annual report must document and summarize implementation of the SWMP 

during the previous year and evaluate program results and describe planned changes towards 

continuous improvement. The annual report also can serve as a “state of the SWMP” report for 

the general public or other stakeholders in the community. While records are to be kept and 

made available to the public, the annual report is an excellent summary document to provide as 

well. 

Recommendations for the Permit Writer 

EPA recommends using its Summary Annual Report Template (see Appendix A) in this guidance in 

order to obtain summary information about the status of MS4 programs. In addition to the 

summary annual report template, permittees must also submit a more detailed annual report. 

The permit writer may determine that additional, more detailed, information is needed to 

determine compliance with the Permit Requirements. Even if these reporting details are not 

required within the permit, the permitting authority and enforcement officials can still request them 

at any time or during a program audit. 

MS4 permits should require permittees to summarize and analyze data concerning the effectiveness 

of the SWMP and submit the analysis to the permitting authority. For example, the permittees 

should address such questions as: 

 For illicit discharge data, what are the most prevalent sources and pollutants in the illicit 

discharge data, and where are these illicit discharges occurring? How many illicit discharges 

have been identified, and how many of those have been resolved? How many outfalls or 

screening points were visually screened, how many had dry weather discharges or flows, at how 

many were field analyses completed and for what parameters, and at how many were samples 

collected and analyzed? Does the MS4 need to conduct more inspections in these areas, or 

develop more specific outreach targeting these sources and pollutants? 

 For the construction data, what are the most common construction violations, and are there any 

trends in the data (e.g., construction operators who receive more violations than others, areas 

of the MS4 with more violations, need to refine guidance or standards to more clearly address 

common violations). How has the permittee responded to these trends? Over the last year, 

how many construction site plan reviews were completed and approved? How many 

inspections were conducted, how many noncompliant sites were identified, and how many 

enforcement actions (and of what type) were taken? 

At a minimum, the permit should require that the annual report clearly illustrate three key items for 

each SWMP area: 

 Summary of the Year’s Activities. The summary should describe and quantify program activities 

for each SWMP component. Responsible persons, agencies, departments or co-permittees 

should be included. Each activity should be described in relation to achievement of established 

goals or performance standards. 

Chapter 8: Monitoring, Evaluation, and Reporting 105
MS4 Permit Improvement Guide 

 Description of SWMP Effectiveness. An annual report should not only describe the previous 

year’s activities, but should also highlight the SMWP’s effectiveness (see Part 8.3) using the 

indicators required in Part 8.2. 

 Planned Activities and Changes. The annual report should describe activities planned for the 

next year highlighting any changes made to improve control measures or program effectiveness. 

Also, although the stormwater Phase II rule requires reports, after the first permit term, to be 

submitted in only years two and four of the permit term, EPA strongly encourages annual reports for 

all permittees. 

Chapter 8: Monitoring, Evaluation, and Reporting 106
MS4 Permit Improvement Guide 

Appendix A: Summary Annual Report Template 107

APPENDIX A: SUMMARY ANNUAL REPORT TEMPLATE
National Pollutant Discharge Elimination System Stormwater Program 

Small MS4 Report Form 

The purpose of this report is to contribute information to an evaluation of the NPDES small municipal separate storm sewer 

system (MS4) permit program. Consistent with 40 CFR §122.37 the U.S. Environmental Protection Agency is assessing the 

status of the program nation-wide. A “no” answer to a question does not necessarily mean noncompliance with your permit or 

with the federal regulations. In order to establish the range of variability in the program it is necessary to ask questions along a 

fairly broad performance continuum. Your permitting authority may use some of this information as one component of a 

compliance evaluation. 

1. MS4 Information 

 

Name of MS4 

 

Name of Contact Person (First) (Last) (Title) 

 

Telephone (including area code) Email 

 

Mailing Address 

 

City State ZIP code 

What size population does your MS4 serve? NPDES number 

What is the reporting period for this report? (mm/dd/yyyy) From to 

2. Water Quality Priorities 

A. Does your MS4 discharge to waters listed as impaired on a state 303(d) list? Yes No 

B. If yes, identify each impaired water, the impairment, whether a TMDL has been approved by EPA for each, and whether 

the TMDL assigns a wasteload allocation to your MS4. Use a new line for each impairment, and attach additional pages as 

necessary. 

Impaired Water Impairment Approved TMDL TMDL assigns WLA to MS4

 Yes No Yes No 

 Yes No Yes No 

 Yes No Yes No 

 Yes No Yes No 

 Yes No Yes No 

 Yes No Yes No 

 Yes No Yes No 

 Yes No Yes No 

C. What specific sources contributing to the impairment(s) are you targeting in your stormwater program? 

 

D. Do you discharge to any high-quality waters (e.g., Tier 2, Tier 3, outstanding natural resource 

waters, or other state or federal designation)? Yes No 

E. Are you implementing additional specific provisions to ensure their continued integrity? Yes No 
Small MS4 Annual Report Form (cont) 2 

3. Public Education and Public Participation 

A. Is your public education program targeting specific pollutants and sources of those pollutants? Yes No 

B. If yes, what are the specific sources and/or pollutants addressed by your public education program? 

 

C. Note specific successful outcome(s) (e.g., quantified reduction in fertilizer use; NOT tasks, events, publications) fully 

or partially attributable to your public education program during this reporting period. 

 

D. Do you have an advisory committee or other body comprised of the public and other 

stakeholders that provides regular input on your stormwater program? Yes No 

4. Construction 

A. Do you have an ordinance or other regulatory mechanism stipulating: 

 Erosion and sediment control requirements? Yes No 

 Other construction waste control requirements? Yes No 

 Requirement to submit construction plans for review? Yes No 

 MS4 enforcement authority? Yes No 

B. Do you have written procedures for: 

 Reviewing construction plans? Yes No 

 Performing inspections? Yes No 

 Responding to violations? Yes No 

C. Identify the number of active construction sites > 1 acre in operation in your jurisdiction at any time during the 

reporting period. 

D. How many of the sites identified in 4.C did you inspect during this reporting period? 

E. Describe, on average, the frequency with which your program conducts construction site inspections. 

 

F. Do you prioritize certain construction sites for more frequent inspections? Yes No 

 If Yes, based on what criteria? 

G. Identify which of the following types of enforcement actions you used during the reporting period for construction 

activities, indicate the number of actions, or note those for which you do not have authority: 

 Yes Notice of violation # No Authority 

 Yes Administrative fines # No Authority 

 Yes Stop Work Orders # No Authority 

 Yes Civil penalties # No Authority 

 Yes Criminal actions # No Authority 

 Yes Administrative orders # No Authority 

 Yes Other # 

H. Do you use an electronic tool (e.g., GIS, data base, spreadsheet) to track the locations, 

inspection results, and enforcement actions of active construction sites in your jurisdiction? Yes No 

I. What are the 3 most common types of violations documented during this reporting period? 

 

J. How often do municipal employees receive training on the construction program? 
Small MS4 Annual Report Form (cont) 3 

5. Illicit Discharge Elimination 

A. Have you completed a map of all outfalls and receiving waters of your storm sewer system? Yes No 

B. Have you completed a map of all storm drain pipes and other conveyances in the storm sewer 

system? Yes No 

C. Identify the number of outfalls in your storm sewer system. 

D. Do you have documented procedures, including frequency, for screening outfalls? Yes No 

E. Of the outfalls identified in 5.C, how many were screened for dry weather discharges during this reporting period? 

 

F. Of the outfalls identified in 5.C, how many have been screened for dry weather discharges at any time since you obtained 

MS4 permit coverage? 

G. What is your frequency for screening outfalls for illicit discharges? Describe any variation based on size/type. 

 

H. Do you have an ordinance or other regulatory mechanism that effectively prohibits illicit 

discharges? Yes No 

I. Do you have an ordinance or other regulatory mechanism that provides authority for you to 

take enforcement action and/or recover costs for addressing illicit discharges? Yes No 

J. During this reporting period, how many illicit discharges/illegal connections have you discovered? 

K. Of those illicit discharges/illegal connections that have been discovered or reported, how many have been eliminated? 

 

L. How often do municipal employees receive training on the illicit discharge program? 

6. Stormwater Management for Municipal Operations 

A. Have stormwater pollution prevention plans (or an equivalent plan) been developed for: 

All public parks, ball fields, other recreational facilities and other open spaces Yes No 

All municipal construction activities, including those disturbing less than 1 acre Yes No 

All municipal turf grass/landscape management activities Yes No 

All municipal vehicle fueling, operation and maintenance activities Yes No 

All municipal maintenance yards Yes No 

All municipal waste handling and disposal areas Yes No 

Other 

B. Are stormwater inspections conducted at these facilities? Yes No 

C. If Yes, at what frequency are inspections conducted? 

D. List activities for which operating procedures or management practices specific to stormwater management have been 

developed (e.g., road repairs, catch basin cleaning). 

 

E. Do you prioritize certain municipal activities and/or facilities for more frequent inspection? Yes No 

F. If Yes, which activities and/or facilities receive most frequent inspections? 

G. Do all municipal employees and contractors overseeing planning and implementation of 

stormwater-related activities receive comprehensive training on stormwater management? Yes No 

H. If yes, do you also provide regular updates and refreshers? Yes No 

I. If so, how frequently and/or under what circumstances? 
Small MS4 Annual Report Form (cont) 4 

7. Long-term (Post-Construction) Stormwater Measures 

A. Do you have an ordinance or other regulatory mechanism to require: 

Site plan reviews for stormwater/water quality of all new and re-development projects? Yes No 

Long-term operation and maintenance of stormwater management controls? Yes No 

Retrofitting to incorporate long-term stormwater management controls? Yes No 

B. If you have retrofit requirements, what are the circumstances/criteria? 

 

C. What are your criteria for determining which new/re-development stormwater plans you will review (e.g., all projects, 

projects disturbing greater than one acre, etc.) 

D. Do you require water quality or quantity design standards or performance standards, either 

directly or by reference to a state or other standard, be met for new development and 

re-development? 

 Yes No 

E. Do these performance or design standards require that pre-development hydrology be met for: 

Flow volumes Yes No 

Peak discharge rates Yes No 

Discharge frequency Yes No 

Flow duration Yes No 

F. Please provide the URL/reference where all post-construction stormwater management standards can be found. 

 

G. How many development and redevelopment project plans were reviewed during the reporting period to assess impacts to 

water quality and receiving stream protection? 

H. How many of the plans identified in 7.G were approved? 

I. How many privately owned permanent stormwater management practices/facilities were inspected during the reporting 

period? 

J. How many of the practices/facilities identified in I were found to have inadequate maintenance? 

K. How long do you give operators to remedy any operation and maintenance deficiencies identified during inspections? 

 

L. Do you have authority to take enforcement action for failure to properly operate and maintain 

stormwater practices/facilities? Yes No

M. How many formal enforcement actions (i.e., more than a verbal or written warning) were taken for failure to adequately 

operate and/or maintain stormwater management practices? 

N. Do you use an electronic tool (e.g., GIS, database, spreadsheet) to track post-construction 

BMPs, inspections and maintenance? Yes No 

O. Do all municipal departments and/or staff (as relevant) have access to this tracking system? Yes No 

P. How often do municipal employees receive training on the post-construction program? 

8. Program Resources 

A. What was the annual expenditure to implement MS4 permit requirements this reporting period? 

B. What is next year’s budget for implementing the requirements of your MS4 NPDES permit? 
Small MS4 Annual Report Form (cont) 5 

C. This year what is/are your source(s) of funding for the stormwater program, and annual revenue (amount or percentage) 

derived from each? 

 Source: Amount $ OR % 

 Source: Amount $ OR % 

 Source: Amount $ OR % 

D. How many FTEs does your municipality devote to the stormwater program (specifically for implementing the stormwater 

program; not municipal employees with other primary responsibilities)? 

E. Do you share program implementation responsibilities with any other entities? Yes No 

Entity Activity/Task/Responsibility Your Oversight/Accountability Mechanism

9. Evaluating/Measuring Progress 

A. What indicators do you use to evaluate the overall effectiveness of your stormwater management program, how long have 

you been tracking them, and at what frequency? These are not measurable goals for individual management practices or 

tasks, but large-scale or long-term metrics for the overall program, such as macroinvertebrate community indices, 

measures of effective impervious cover in the watershed, indicators of in-stream hydrologic stability, etc. 

Indicator 

Began Tracking 

(year) Frequency 

Number of 

Locations 

B. What environmental quality trends have you documented over the duration of your stormwater program? Reports or 

summaries can be attached electronically, or provide the URL to where they may be found on the Web. 

 

 

 
Small MS4 Annual Report Form (cont) 6 

10. Additional Information 

In the space below, please include any additional information on the performance of your MS4 program. If providing 

clarification to any of the questions on this form, please provide the question number (e.g., 2C) in your response. 

Certification Statement and Signature 

I certify that all information provided in this report is, to the best of my knowledge and belief, true, 

accurate and complete. Yes 

Federal regulations require this application to be signed as follows: For a municipal, State, Federal, or other public facility: by either a principal 

executive or ranking elected official. 

 

Name of Certifying Official, Title Date (mm/dd/yyyy) 
APPENDIX B: DEFINITIONS

Commencement of Construction – the initial disturbance of soils associated with clearing, grading, or 

excavating activities or other construction-related activities (e.g., stockpiling of fill material). (Source: 

2008 CGP) 

Control Measure – any best management practice (BMP) or other method used to prevent or reduce 

the discharge of pollutants to waters of the United States. (Source: 2008 CGP) 

Discharge – when used without qualification means the “discharge of a pollutant.” (Source: 2008 CGP) 

Discharge of Stormwater Associated with Construction Activity – as used in this permit, refers to a 

discharge of pollutants in stormwater from areas where soil disturbing activities (e.g., clearing, grading, 

or excavation), construction materials or equipment storage or maintenance (e.g., fill piles, borrow area, 

concrete truck chute washdown, fueling), or other industrial stormwater directly related to the 

construction process (e.g., concrete or asphalt batch plants) are located. (Source: 2008 CGP) 

Illicit Discharge - any discharge to a municipal separate storm sewer that is not composed entirely of 

storm water except discharges pursuant to a NPDES permit (other than the NPDES permit for discharges 

from the municipal separate storm sewer) and discharges resulting from fire fighting activities. (Source: 

40 CFR 122.26) 

Large Construction Activity – is defined at 40 CFR §122.26(b)(14)(x) and incorporated here by reference. 

A large construction activity includes clearing, grading, and excavating resulting in a land disturbance 

that will disturb equal to or greater than five acres of land or will disturb less than five acres of total land 

area but is part of a larger common plan of development or sale that will ultimately disturb equal to or 

greater than five acres. Large construction activity does not include routine maintenance that is 

performed to maintain the original line and grade, hydraulic capacity, or original purpose of the site. 

(Source: 2008 CGP) 

Non-Structural Controls – preventative actions that involve management and source controls. Refer 

also to 40 CFR 122.34(b)(5)(c)(iii). (Source: 40 CFR 122.26) 

Qualified Personnel – A person knowledgeable in the principles and practice of erosion and sediment 

controls who possesses the skills to assess conditions at the construction site that could impact 

stormwater quality and to assess the effectiveness of any sediment and erosion control measures 

selected to control the quality of stormwater discharges from the construction activity. (Source: EPA’s 

2008 Construction General Permit) 

Receiving Water – the “Water of the United States” as defined in 40 CFR §122.2 into which the 

regulated stormwater discharges. (Source: 2008 CGP) 

Small Construction Activity –includes clearing, grading, and excavating resulting in a land disturbance 

that will disturb equal to or greater than one (1) acre and less than five (5) acres of land or will disturb 

Appendix B: Definitions 108
Appendix B: Definitions 109

less than one (1) acre of total land area but is part of a larger common plan of development or sale that 

will ultimately disturb equal to or greater than one (1) acre and less than five (5) acres. Small 

construction activity does not include routine maintenance that is performed to maintain the original 

line and grade, hydraulic capacity, or original purpose of the site. (Source: 2008 CGP) 

Stormwater control measure – see control measure.

Structural Control - physically designed, installed, and maintained practices used to prevent or reduce 

the discharge of pollutants in stormwater, to minimize erosion, and/or to minimize the impacts of 

stormwater on waterbodies. 

Wasteload Allocation – the portion of a receiving water's loading capacity that is allocated to one of its 

existing or future point sources of pollution. Wasteload allocations constitute a type of water qualitybased effluent limitation. (40 CFR 130.2)