+-----------------+-----------------+-----------------+-----------------+
|                 | **United States | **Office of     | **EPA           |
|                 | Environmental   | Water**         | 8##-R-03-###**  |
|                 | Protection      |                 |                 |
|                 | Agency**        | **4607**        | **Month 2007**  |
+-----------------+-----------------+-----------------+-----------------+

**Consecutive System Guide for the Ground Water Rule**

**May 1, 2007**

**Draft for Review**

Comments regarding this document should be addressed to

Michael J. Finn

U.S. EPA Office of Ground Water and Drinking Water

Standards and Risk Management Division

1200 Pennsylvania Avenue, N.W. 4607M

Washington, DC 20460

Finn.Michael@epa.gov

202-564-5261

202-564-3767 (facsimile)

**CONTENTS**

[1. Introduction 1-1](#introduction)

[1.1 General requirements of the GWR
1-1](#general-requirements-of-the-gwr)

[2. GWR Requirements for Consecutive and Wholesale Ground Water Systems
2-1](#gwr-requirements-for-consecutive-and-wholesale-ground-water-systems)

[2.1 Is triggered source water monitoring always required?
2-2](#is-triggered-source-water-monitoring-always-required)

[2.2 What if you believe a fecal indicator-positive source water sample
positive is due to a lab error or other cause rather than source water
contamination?
2-2](#what-if-you-believe-a-fecal-indicator-positive-source-water-sample-is-due-to-a-lab-error-or-other-cause-rather-than-source-water-contamination)

[2.3 How should the triggered source monitoring for a consecutive system
with its own sources be conducted?
2-3](#how-should-the-triggered-source-monitoring-for-a-consecutive-system-with-its-own-sources-be-conducted)

[2.4 How should triggered source monitoring for a consecutive system
with more than one connection to a wholesale system (or connections to
more than one wholesale system) be conducted?
2-3](#how-should-triggered-source-monitoring-for-a-consecutive-system-with-more-than-one-connection-to-a-wholesale-system-or-connections-to-more-than-one-wholesale-system-be-conducted)

[2.5 How should triggered source water monitoring for a wholesale system
with multiple wells be conducted?
2-4](#how-should-triggered-source-water-monitoring-for-a-wholesale-system-with-multiple-wells-be-conducted)

[2.6 How can a wholesale system ensure that it meets the requirements
for source water sampling under the GWR?
2-5](#how-can-a-wholesale-system-ensure-that-it-meets-the-requirements-for-source-water-sampling-under-the-gwr)

[3. GWR Consecutive System Examples
3-1](#gwr-consecutive-system-examples)

[3.1 Example 1 (See Figure A-1) 3-1](#example-1-figure-a-1-to-be-added)

[3.2 Example 2 (See Figure A-2) 3-2](#example-2-figure-a-2-to-be-added)

[3.3 Example 3 (See Figure A-3) 3-2](#example-3-figure-a-3-to-be-added)

[4. Example: Triggered Source Water Monitoring Plan -- First Valley
Water System 4-1](#glossary)

[5. Glossary 5-1](#__RefHeading___Toc163119983)

**Abbreviations**

GWR Ground Water Rule (40 CFR Subpart S)

SDWA Safe Drinking Water Act

TCR Total Coliform Rule (40 CFR Subpart C)

LCR Lead and Copper Rule (40 CFR Subpart I)

**For more information**, contact EPA\'s Safe Drinking Water Hotline, 1
(800) 426-4791, or see the Office of Ground Water and Drinking Water web
page at [<http://www.epa.gov/safewater>.]{.underline}

This guidance manual is available electronically at
<http://www.epa.gov/safewater/disinfection/gwr/compliance>help/html. To
order a paper copy of guidance manuals you may contact the US EPA Water
Resource Center at 202-566 -1729 or by mail at :

US Environmental Protection Agency

Water Resource Center (RC-4100)

1200 Pennsylvania Ave NW

Washington DC 20460

E-mail: <center.water.resource@epa.gov>

**Other Guidance Manuals**

EPA has developed other guidance manuals to aid EPA, State agencies, and
you in implementing the GWR and other rules and to help to ensure
consistent implementation.

> **Consider the Source : A Pocket Guide to Protecting Your Source:
> Drinking Water Pocket Guide #3** An electronic version is available at
> http://www.epa.gov/safewater/protect/swpocket.html
>
> **Public Notification Handbook (EPA 816 R 00-010)-**An electronic
> version is available at
> http://www.epa.gov/safewater/pws/pn/handbook.pdf
>
> **Surface Water Treatment Rule Guidance Manual** The Appendices also
> include CT tables for the inactivation of Giardia and viruses for
> chlorine, chlorine dioxide and ozone.
>
> **Complying with the Ground Water Rule: Small Entity Compliance
> Guide(EPA 81#-R-###)-**This guide is designed for owners and operators
> of public water systems serving 10,000 or fewer persons that are
> required to comply with the Ground Water Rule.
>
> **Ground Water Rule Corrective Action Guidance Manual** **(EPA
> 81#-R-###)-**This manual provides information for ground water systems
> that must apply treatment techniques as a result of uncorrected
> significant deficiencies or fecally contaminated source water. The
> guidance includes technical information on selecting appropriate
> disinfection technologies to enable primacy agencies and PWSs to
> select the treatment most appropriate for a given system. Also
> provides technical information to States and systems on eliminating
> sources of contamination, utilizing alternate sources and correcting
> significant deficiencies for situations in which disinfection is not
> the selected treatment technique.

**Sanitary Survey Guidance Manual for Ground Water Systems(EPA
81#-R-###)-**This guidance is provides information to assist States and
other primacy programs in conducting sanitary surveys of ground water
systems.

**Ground Water Rule Source Water Monitoring Guidance Manual (EPA
81#-R-###) -**This manual provides guidance on triggered and optional
assessment source water monitoring issues such as: Selection of fecal
indicators, sample collection and shipping, source water monitoring
methods, laboratory quality assurance (QA) and quality control (QC), and
evaluation of fecal indicator data. This manual also provides an
overview of GWR requirements and includes frequently asked questions
regarding source water monitoring.

**Ground Water Rule Source Water Assessment Guidance (EPA
81#-R-###)-**This manual provides information on procedures for
identifying ground water sources at risk for contamination. Risk factors
are discussed with emphasis on identifying readily available factors
suitable for office, rather than field determination, of risk at an
individual PWS well. The guidance also lists sources of information for
making determinations and includes field methods for determining the
presence of a hydrogeologic barrier. EPAs recommended source water
assessment monitoring is included.

# Introduction

This guide describes the regulatory requirements of the Ground Water
Rule (GWR) as it applies to wholesale systems that supply ground water
and to the consecutive water systems that receive and distribute that
ground water supply.

.

+-----------------------------------------------------------------------+
| The GWR applies to all public water systems that use **ground water   |
| unless** the system combines all its ground water with surface water  |
| **prior** to treatment under 40 CFR 141 Subpart H(Filtration and      |
| Disinfection)                                                         |
|                                                                       |
| A **wholesale system** is public water system that supplies finished  |
| water to one or more other public water systems.                      |
|                                                                       |
| A **consecutive system** is a public water system that buys or        |
| otherwise receives some or all of its finished water from a wholesale |
| system.                                                               |
+-----------------------------------------------------------------------+

This document is intended to provide guidance to wholesale and
consecutive ground water systems and States in applying one of the main
components of the GWR, risk-based source water monitoring to identify
fecal contamination of ground water sources.

Consecutive systems, and wholesale /consecutive system interactions and
contractual relationships, can be complex. There are a variety of State
approaches to addressing regulatory requirements for consecutive systems
since most previous regulations under the SDWA did not specifically
address consecutive systems.

In the development of the GWR, the Stage 2 Disinfectants and
Disinfection Byproducts Rule and the Long Term 2 Enhanced Surface Water
Treatment Rule under the SDWA, EPA has explicitly addressed the
applicability of regulations to consecutive systems. EPA is providing
guidance to assist public water systems and States in implementing
regulations addressing consecutive systems*.*

## 1.1 General requirements of the GWR {#general-requirements-of-the-gwr .unnumbered}

The requirements of the GWR (40 CFR Subpart S) constitute national
primary drinking water regulations. The GWR was published in the Federal
Register on November 8, 2006, (Federal Register Volume 71, Number 216,
65574 available at
http://www.epa.gov/fedrgst/EPA-WATER/2006/November/Day-08/w8763.pdf). A
copy of the rule language can be found on EPA's website at
<http://www.epa.gov/safewater/disnifection/gwr/regulations.html>.

The following are general GWR requirements applicable to wholesale and
consecutive ground water systems :

+-----------------------------------------------------------------------+
| \(a\) Provide existing information to the State to aid the State in   |
| performing a sanitary survey of your system.                          |
|                                                                       |
| \(b\) Wholesale systems and consecutive systems with their own ground |
| water sources must perform triggered microbial monitoring of ground   |
| water source(s) after a routine Total Coliform Rule (TCR)-positive    |
| sample if they do not provide 4-log (99.99 percent) treatment (by     |
| inactivation, removal or a combination of inactivation or removal)    |
| for the source.                                                       |
|                                                                       |
| \(c\) A consecutive system is required to report TCR- positive        |
| samples to the wholesale supplier(s) []{.mark}within 24 hours of      |
| being notified of the TCR-positive sample. unless the consecutive     |
| system or wholesale system(s) provide 4-log (99.99 percent) treatment |
| (by inactivation, removal or a combination of inactivation or         |
| removal) for the wholesale ground water source(s).                    |
|                                                                       |
| \(d\) A wholesale system is required to notify the consecutive        |
| system(s) of a fecal indicator- positive ground water source sample   |
| within 24 hours of being notified of the fecal indicator- positive    |
| sample.                                                               |
|                                                                       |
| \(e\) Correct any significant deficiencies identified by the State in |
| your system or correct fecal contamination of your ground water       |
| source(s).                                                            |
|                                                                       |
| \(f\) If required, provide existing information to the State to aid   |
| the State in performing a hydrogeologic sensitivity assessment for    |
| your source(s).                                                       |
|                                                                       |
| \(g\) Wholesale systems and consecutive systems with their own ground |
| water sources must perform assessment microbial monitoring of ground  |
| water source(s) if required by the State.                             |
|                                                                       |
| \(h\) If required, monitor any treatment process used to provide      |
| 4-log (99.99 percent) treatment (by inactivation, removal or a        |
| combination of inactivation or removal) of viruses for your           |
| source(s), and                                                        |
|                                                                       |
| \(i\) Keep records and report to the State for some of the            |
| requirements listed in (a)-(h) above.                                 |
+-----------------------------------------------------------------------+

The requirements specific to wholesale and consecutive systems are
discussed in greater detail in the next section.

# GWR Requirements for Consecutive and Wholesale Ground Water Systems

Exhibit 2.1 describes the specific responsibilities of consecutive and
wholesale ground water systems under the GWR.

**Exhibit 2.1 GWR Requirements for Wholesale and Consecutive Systems\
(Yes=Required, No=Not Required)**

+------------------------------------+---------+-----------+----------+
| **Ground Water Rule Requirement**  | **Wh    | **Co      | **Con    |
|                                    | olesale | nsecutive | secutive |
|                                    | S       | System    | system - |
|                                    | ystem** | -100% of  | p        |
|                                    |         | supply    | urchased |
|                                    |         | pu        | and own  |
|                                    |         | rchased** | supply** |
+------------------------------------+---------+-----------+----------+
| Provide the State with information | Yes     | Yes       | Yes      |
| it requests to complete the        |         |           |          |
| sanitary survey                    | Yes     | No        | Yes      |
|                                    |         |           |          |
| If directed by the State, provide  | Yes     | Yes       | Yes      |
| the State with information it      |         |           |          |
| requests to complete the           | No      | Yes       | Yes      |
| hydrogeologic sensitivity          |         |           |          |
| assessment for your water system.  | Yes     | No        | Yes      |
|                                    |         |           |          |
| Correct any significant            | Yes     | No        | No       |
| deficiencies identified by the     |         |           |          |
| State.                             | Yes     | No        | No       |
|                                    |         |           |          |
| Notify your wholesale supplier     | Yes     | No        | Yes      |
| within 24 hours of being notified  |         |           |          |
| by your laboratory of a TCR-       | Yes     | No        | Yes      |
| positive sample in your            |         |           |          |
| distribution system **if you or    | Yes     | Yes       | Yes      |
| your wholesale supplier do not     |         |           |          |
| provide** 4-log treatment of       |         |           |          |
| viruses for your ground water      |         |           |          |
| supply.                            |         |           |          |
|                                    |         |           |          |
| Triggered ^1^source water          |         |           |          |
| monitoring of your own sources ^2^ |         |           |          |
| **if you do not provide** 4-log    |         |           |          |
| treatment of viruses for those     |         |           |          |
| sources                            |         |           |          |
|                                    |         |           |          |
| Triggered^1^ source water          |         |           |          |
| monitoring of your source(s)^2^    |         |           |          |
| **if** you are notified of TCR-    |         |           |          |
| positive distribution sample by a  |         |           |          |
| consecutive system you serve **and |         |           |          |
| if** you or the consecutive system |         |           |          |
| **do not** provide a 4-log         |         |           |          |
| treatment of viruses for your      |         |           |          |
| sources.                           |         |           |          |
|                                    |         |           |          |
| Notify consecutive systems you     |         |           |          |
| serve if a ground water source     |         |           |          |
| sample is fecal                    |         |           |          |
| indicator-positive.                |         |           |          |
|                                    |         |           |          |
| If directed by the State, conduct  |         |           |          |
| assessment source water monitoring |         |           |          |
| of your ground water sources.      |         |           |          |
|                                    |         |           |          |
| Corrective action and/or treatment |         |           |          |
| of your groundwater sources, **if  |         |           |          |
| required**, **after** a fecal      |         |           |          |
| indicator-positive source water    |         |           |          |
| sample.                            |         |           |          |
|                                    |         |           |          |
| Reporting, record keeping and      |         |           |          |
| public notification requirements   |         |           |          |
| of the GWR                         |         |           |          |
+------------------------------------+---------+-----------+----------+

**1** Triggered source monitoring consists of collecting a sample from
your ground water sources(s) after a routine TCR- positive sample and
analyzing the sample for a fecal indicator approved by the State.

**2** All sources do not have to be monitored under triggered monitoring
if a "triggered source water monitoring plan" has been developed and
approved by the State.

## Is triggered source water monitoring always required?

A wholesale system or a consecutive system with its own groundwater
source(s) that has evidence that the TCR- positive sample is due to
distribution system contamination, rather than source water
contamination, may apply to the State for an exception to the triggered
source water monitoring requirements on a case-by-case basis.

-   The State is then required to make a determination that the total
    coliform-positive sample is caused by a distribution system
    deficiency.

-   If the State decides to grant an exception to the triggered source
    water monitoring requirements, then a State official must document
    the decision, including the rationale for the decision, in writing
    and sign the document.

-   You should have information that demonstrates the distribution
    problem that caused the positive sample available for the State when
    you make your request for an exception.

The State may also establish criteria for distribution system conditions
that will cause total-coliform positive samples. If the total
coliform-positive sample was collected under conditions that meet those
State-specified criteria, you are not required to conduct triggered
source water monitoring. You must notify the State within 30 days of the
total coliform-positive sample that met State criteria for an exception
to the triggered monitoring requirements of the GWR. You should become
familiar with State criteria for exceptions to triggered monitoring.

## What if you believe a fecal indicator-positive source water sample is due to a lab error or other cause rather than source water contamination?

The State may invalidate a fecal indicator-positive source sample if the
laboratory establishes that improper sample analysis occurred or if the
State has substantial grounds to believe that a sample result is due to
circumstances that do not reflect source water quality.

-   If the State invalidates a fecal indicator-positive sample, then the
    GWR requires that a State official document the decision in writing.

-   You should have information from the laboratory about the analysis
    or information that demonstrates the fecal indicator-positive does
    not reflect source water quality available for the State to review
    when you make your request to invalidate.

-   If the State invalidates a fecal indicator-positive source water
    sample, the GWR requires that the system must collect another source
    water sample and have it analyzed for the same fecal indicator
    within 24 hours of being notified of the invalidation.

## How should the triggered source monitoring for a consecutive system with its own sources be conducted?

One of the main elements of the GWR is to identify contaminated ground
water sources through sampling and correct them as needed. If a
consecutive system that has its own source(s) of ground water has a
TCR-positive sample in its distribution system and does not know which
source is the cause, it must sample its source(s) and must notify its
wholesale supplier as required by the GWR.

However, if the consecutive system can identify portions of its system
that are served by only one source, monitoring of all the sources may
not be necessary. Consecutive systems with their own sources should
review their distribution systems and available water quality data to
determine if certain parts of its system are served by a particular
source. Information that could help identify areas served by a
particular source includes:

-   Distribution system maps with pressure zones, isolation valves,
    storage tanks, sources, flow meters, and any other significant
    facilities identified

-   Normally closed valves between service areas or pressure zones

-   Water quality information that identifies a particular source
    (alkalinity, pH, disinfectant residual, fluoride, Lead and Copper
    Rule parameters etc.)

-   Distribution system models (proprietary software , EPANET) These
    tools need to be properly calibrated and verified for valid results
    in a specific distribution system

If sufficient information is available, it may be possible to associate
a routine TCR monitoring site with a particular source. In the event of
a TCR-positive sample at such a site, the system and the State can be
confident that the correct source is being sampled.

A triggered source water monitoring plan can help ensure the correct
source is sampled without collecting unnecessary samples. Under the GWR,
States may require a triggered source water monitoring plan to be
submitted for systems with more than one ground water source. Even if
your State does not require you to submit a triggered source water
monitoring plan, you may wish to develop one anyway and discuss it with
your State. You may also want to develop a monitoring plan if you rotate
the wells you use on a regular basis or if you only use a well during
certain times of the year. The GWR requires that a triggered source
sample be collected within 24 hours of being notified of a TCR- positive
sample. A triggered source water monitoring plan can help you make a
decision about where to collect a sample more rapidly.

## How should triggered source monitoring for a consecutive system with more than one connection to a wholesale system (or connections to more than one wholesale system) be conducted?

A consecutive system with multiple connections to a wholesale system or
with connections to more than one wholesale system may not know which
connection is responsible for a TCR- positive sample in its distribution
system. If the system does not know which connection could be the cause
and has more than one wholesale supplier, it must notify all its
wholesale suppliers as required by the GWR. However, if the consecutive
system can identify portions of its system that are served by a
particular connection, monitoring of all the wholesale sources may not
be necessary.

Wholesale systems that serve through multiple connections should review
their distribution system and available water quality data to determine
if certain consecutive systems or certain connections are served by a
particular source. As in the previous discussion, water quality data,
pressure zone and valve maps and modeling can be useful in determining
if a particular consecutive system connection is served by particular
source. This would also apply to wholesale systems that serve
consecutive systems served by multiple wholesale system(s). If there is
sufficient information to demonstrate that a particular sample location
in a consecutive system is served by a particular wholesale supply, then
the required triggered source water monitoring may not have to be
completed for all sources.

For wholesale systems with multiple consecutive systems and consecutive
systems with multiple wholesale suppliers, the decision about where to
collect a source water sample may not be straightforward. As discussed
previously, a triggered source water monitoring plan can help ensure the
correct source is sampled without collecting unnecessary samples. States
may require a triggered source water monitoring plan to be submitted for
consecutive systems. Even if your State does not require you to submit a
triggered source water monitoring plan, you may wish to develop one and
have it approved by your State.

-   A triggered source water monitoring plan is particularly useful for
    wholesale systems with multiple consecutive systems and multiple
    sources and for consecutive systems with their own sources or
    multiple wholesale suppliers.

-   Wholesale and consecutive systems may also want to develop a
    triggered source water monitoring plan if they rotate the wells used
    on a regular basis or only use a well during certain times of the
    year.

## How should triggered source water monitoring for a wholesale system with multiple wells be conducted? 

Most wholesale ground water systems will have more than one well. The
wells may not draw from the same aquifer or certain wells may not serve
certain parts of the system or customers. Once the wholesale system is
notified of a TCR- positive by one of its consecutive systems it must
decide (within 24 hours) where to collect the required source water
samples and collect the sample.

-   If you are a wholesale system with more than one ground water source
    and you cannot identify which wells serve the consecutive system, or
    identify a well or wells representative of the ground water you
    supplied, you must sample all your sources.

-   A representative well (or wells) should represent all your ground
    water sources that have the potential to serve the area that had the
    total-coliform positive sample. Use of a representative well (or
    wells) requires State approval.

-   If a well (or wells) only serve some of the consecutive systems or
    portions of the wholesale distribution system and you provide this
    information to the State in a triggered source water monitoring
    plan, you may be able to sample only the source(s) that serves the
    system, or portions of the system, with a TCR- positive.

## How can a wholesale system ensure that it meets the requirements for source water sampling under the GWR?

##  {#section .unnumbered}

Under the GWR, a wholesale system is responsible for collecting source
water samples after being notified of a TCR- positive in its own or any
of its consecutive system's distribution system(s). Information about
and communication with the consecutive systems is needed to meet the GWR
requirements

Steps a wholesale system can take to ensure that it is notified of TCR-
positives in the consecutive systems it serves include:

-   Identify all consecutive systems subject to the TCR and to triggered
    source water monitoring under the GWR.

-   Identify all connection(s) to those consecutive systems. Include
    information about the source and status (active, standby, abandoned
    etc.) of each connection. Identify who has the ability to alter the
    status of the connection and the date the status was last confirmed,
    if applicable.

-   Identify those consecutive systems with their own ground water
    sources and those supplied by another wholesale water system.

-   Identify a contact (and alternates and after hours contacts) for
    each consecutive system, keep a record of contact phone numbers, and
    develop a procedure to keep the contact list up to date and
    accurate.

-   Identify the local laboratories used by the consecutive systems and
    contacts in those laboratories. With cooperation of the consecutive
    systems and the laboratory, develop a response plan for notification
    of any TCR-positive samples from either the wholesale system or the
    consecutive system.

-   Identify staff contacts within the wholesale systems for consecutive
    system communication and liaison functions.

-   Develop a documentation process for all communications.

It is also important to establish a communication process for the
consecutive systems to notify the wholesale system of TCR-positive
samples and be aware of water quality and operational issues in the
wholesale systems. Communication processes could include:

-   Dedicated phone lines with after hours forwarding or recorded
    message capacity.

-   Web based information pages and message posting.

-   Pager, cell phone and wireless message transmission.

-   E-mail notification.

-   Laboratory notification of both the consecutive and wholesale system
    for a TCR- positive.

# GWR Consecutive System Examples

## Example 1 (Figure A-1 to be added)

-   The First Valley Water District purchases ground water from the Big
    Mountain Water District in addition to having one well.

-   The First Valley supply is delivered through valved connections from
    Big Mountain's Cross County Pipeline.

-   First Valley Water District also has its own well that is used
    routinely.

-   Pressure in the Big Mountain supply is only adequate to serve the
    low zone of the systems.

-   Some mixing of the Big Mountain supply and First Valley's own supply
    occurs between the low and the high zone (Mixed Zone).

-   The Big Mountain supply can only reach the high zone when the Walnut
    Grove Pump Station is operated to move water between zones and this
    occurs only when the Alder Grove Well is out of service or in an
    emergency (fire, major leak).

Based on the hydraulics of the First Valley system:

-   A TCR- positive sample in the low zone (TCR sites 1 and 2) triggers
    source water sampling in the Big Mountain Water District's sources.

-   A TCR- positive sample in the high zone (TCR sites 5 and 6) triggers
    a source water sample from the Alder Grove Well. This is true as
    long as the Walnut Grove Pump Station was not operating at the time
    of the TCR-positive sample collection.

-   The mixed zone contains water from both sources. Since a single
    source cannot be identified for this zone, triggered source water
    samples must be collected from both the Big Mountain source(s) and
    the Alder Grove Well after a TCR- positive in the mixed zone (TCR
    sites 3 and 4).

In this example, system hydraulics and operation allow for some of the
routine TCR monitoring sites to be identified as supplied by only one of
the First Valley District's sources. The GWR requires that source water
samples be collected no more than 24 hours after being notified of a
TCR- positive sample, or for a wholesale system, no more than 24 hours
after being notified by their consecutive system of TCR- positive in the
consecutive system's distribution system. To meet these requirements, it
important that samples be properly identified and that system personnel
are aware of the correct response to a TCR- positive at a particular
sample location. Also, the State would have to approve representative
sampling or a triggered source water monitoring plan.

## Example 2 (Figure A-2 to be added)

The Second Valley Water District purchases its entire supply from the
Big Mesa Water District and the Third Valley Water District.

-   Second Valley has three pressure zones in its system.

-   Two zones are served by connection to Big Mesa; the third zone is
    served by a connection to a Third Valley Water District pipeline.

-   The Big Mesa Water District adds chlorine to its groundwater supply
    but does not provide a 4 log inactivation of viruses.

-   The Third Valley Water District adds chloramine to its supply.

-   The Third Valley supply is a mix of surface water and ground water
    depending on the time of year and Second Valley provides a 4 log
    virus inactivation for its groundwater supply.

-   The three zones are interconnected but the Second Valley operators
    keeps the connections between the zones at valves and pump stations
    closed to prevent mixing and the taste and odor complaints that
    often happen when the two supplies mix.

    In this example, there are multiple wholesale sources, however the
    two sources do not mix under normal conditions. If a TCR positive
    occurred in the Second Valley system,

-   A source water sample from the Big Mesa sources would be required
    for a TCR positive in the two zones served by the Big Mesa supply

-   No source water sample would be required for TCR positive sample
    that occurred in the zone served by the Third Valley supply since
    Third Valley provides a 4 log virus inactivation for its sources.

## Example 3 (Figure A-3 to be added)

The Fourth Valley Water District purchases its entire supply from the
Big Gulch Water District and the Last Valley Water District. Fourth
Valley has three pressure zones in its system. One zone is served by
connection to Big Gulch the other two zones are served by connections to
the Last Valley Water District transmission pipeline.

-   The Big Gulch Water District adds chlorine to its wholesale supply
    but do not provide a 4 log inactivation of viruses.

-   The Last Valley Water District supply is a mix of surface water and
    ground water.

    The Last Valley Water District also adds chlorine to its supply but
    does not provide a 4 log inactivation of viruses for its ground
    water sources.

-   The Last Valley Water District surface water supply has a low
    alkalinity and the Last Valley District adjust the pH to protect its
    pipelines and meet the water quality parameters set by the State
    under the Lead and Copper Rule.

-   As Fourth Valley has conducted its Lead and Copper Rule water
    quality parameters tap sampling it has identified the parts of its
    service area that receive the Second Valley supply. That information
    has been put on a distribution system map along with the locations
    of the routine TCR monitoring sites.

    This example is more complicated than the first two because Fourth
    Valley has two wholesale supplies with both surface and groundwater
    sources and multiple pressure zones. For large wholesale systems
    with multiple customers and multiple sources deciding where to
    collect the required source water samples could be even more
    complicated.

    In this example, Fourth Valley has information it collected for the
    Lead and Copper Rule that could allow it to identify the wholesale
    supply at any of its routine TCR monitoring sites and reduce the
    number of source water samples that must be collected. The water
    quality information combined with a sampling plan would allow the
    Fourth Valley system to quickly identify the source and notify the
    correct wholesale supplier.

#  [[]{#__RefHeading___Toc163119983 .anchor}]{.mark}Example: Triggered Source Water Monitoring Plan -- First Valley Water System

+----------------+---------------+-----------------+------------------+
| Routine TCR    | Served by     | Source sample   | Comme            |
| site           |               | at/by           | nts/Instructions |
+----------------+---------------+-----------------+------------------+
| #1 Turnout     | Big Mountain  | Big Mountain WD | Contact Big      |
| Valve lot      |               |                 | Mountain WD      |
|                |               |                 | Water Quality    |
|                |               |                 | Section          |
+----------------+---------------+-----------------+------------------+
| #2 Redwood     | Big Mountain  | Big Mountain WD | Day phone:       |
| Park           |               |                 |                  |
|                |               |                 | Fax:             |
|                |               |                 |                  |
|                |               |                 | After hours:     |
+----------------+---------------+-----------------+------------------+
| #3 Old Town    | Both          | Big Mountain WD | Contact Big      |
|                |               |                 | Mountain WD      |
|                |               | First Valley WD | Water Quality    |
|                |               | (Alder Grove    | Section.         |
|                |               | Well sample     |                  |
|                |               | tap)            | Contact lab for  |
|                |               |                 | sample pick up.  |
|                |               |                 |                  |
|                |               |                 | Day phone:       |
|                |               |                 |                  |
|                |               |                 | Fax:             |
|                |               |                 |                  |
|                |               |                 | After hours :    |
+----------------+---------------+-----------------+------------------+
| \# 4 Walnut    | Both          | Big Mountain WD | Sample bottles   |
| Grove PS       |               |                 | at corp yard     |
|                |               | FV (Alder Grove | -label as SOURCE |
|                |               | Well sample     | and follow chain |
|                |               | tap)            | of custody       |
+----------------+---------------+-----------------+------------------+
| \# 5           | Alder Grove   | FV (Alder Grove | Contact lab for  |
| Freshwater     | Well          | Well sample     | sample pick up.  |
| School         |               | tap)            |                  |
+----------------+---------------+-----------------+------------------+
| \# 6           | Alder Grove   | FV (Alder Grove | Sample bottles   |
| Corporation    | Well          | Well sample     | at corp yard     |
| Yard           |               | tap)            | -label as SOURCE |
|                |               |                 | and follow chain |
|                |               |                 | of custody       |
+----------------+---------------+-----------------+------------------+

# []{.mark}  {#section-1 .unnumbered}

# Glossary {#glossary .unnumbered}

**Fecal Indicator** -- Microorganisms (i.e. bacteria and viruses) that
are closely associated with fecal contamination and indicate that a
source of water may be fecally contaminated. For the GWR, fecal
indicators are *E.Coli*, enterococci or coliphage as specified by the
State.

**Sanitary survey** -- A "sanitary survey," as conducted by the State,
includes but is not limited to an onsite review of the water source
(identifying sources of contamination by using results of source water
assessments or other relevant information, where available), facilities,
equipment, operation, maintenance, and monitoring compliance of a public
water system to evaluate the adequacy of the system, its sources and
operations and the distribution of safe drinking water.

**Significant deficiency** -- A "significant deficiency" includes, but
is not limited to: a defect in design, operation, or maintenance, or a
failure or malfunction of the sources, treatment, storage, or
distribution system that the State determines to be causing, or has the
potential for causing the introduction of contamination into the water
delivered to consumers.

**State** -- Refers to the agency of the State or Tribal government
which has jurisdiction over public water systems. During any period when
a State or Tribal government does not have primary enforcement
responsibility pursuant to Section 1413 of the Safe Drinking Water Act,
the term 'State' means the Regional Administrator, U.S. Environmental
Protection Agency.

**Source sample** -- A sample collected at the source of water for the
public water system before treatment or the distribution system (i.e at
the wellhead)

**Subpart H system --** A public water system serving surface water or
ground water under the influence of surface water. These systems are
subject to the filtration and disinfection requirements of 40 CFR
Subpart H.

**TCR- positive sample** -- A sample collected to meet the TCR
requirements that has been found to have total coliform present.

**Treatment technique violation --** Violation of a treatment technique
established in lieu of a Maximum Contaminant Level. For the GWR this
includes failure to provide corrective action for fecal contamination of
ground water source and failure to correct significant deficiencies.
Treatment technique violations require the system to provide public
notification and systems in violation of treatment technique
requirements are subject to enforcement actions by the State and EPA.

**Triggered Monitoring** -- For the GWR, ground water source samples
collected after a routine TCR- positive sample and analyzed for a fecal
indicator. Triggered monitoring consists of collection of source water
samples and analysis of those samples for a fecal indicator specified by
the State or systems collecting one routine TCR sample or fewer each
month, one of the four repeat samples required under the TCR may be
collected from the ground water source to satisfy the triggered ground
water source monitoring requirements of the GWR .The GWR is not
applicable to any source determined by the State to groundwater under
the direct influence of surface water (GWUDI).

**Well**- For the purposes of the GWR, the term "well" includes springs,
spring boxes, vertical and horizontal wells, infiltration galleries and
any other method of delivering ground water.

**Wholesale system** -- A wholesale system is a public water system that
treats source water as necessary to produce finished water and then
delivers some or all of that finished water to another public water
system. Delivery may be through a direct connection or through the
distribution system.