Underground Storage Tank 

Flood Guide

 

 Junction, Texas Flood of 1935. Photo courtesy of Texas Escapes Online Magazine and Texas Department of Transportation

Printed on Recycled Paper
Contents

Introduction ............................................................................................1

Effects Of Flooding On Underground Storage Tank Systems.................2

What If An UST Is Located In A Flood Area? .........................................4

Before A Flood, What Should Owners And Operators Do? ....................6

After A Flood, What Should Owners And Operators Do? .......................7

What If A Tank Floats Out Of Its Excavation? ........................................8

What If A Remediation System is Flooded? ...........................................9

Other Useful Information ......................................................................10

Incident Response................................................................................11

Financial Assistance.............................................................................11

References...........................................................................................14

Appendix A – API Checklist..................................................................16

Appendix B - Selected State Information On Returning Flood Impacted 

USTs To Service ..................................................................................17
Underground Storage Tank Flood Guide 1

Note: EPA designed this underground storage tank guide to provide simple 

guidelines and useful information to state, local, and tribal authorities in the 

event of a threatened or actual flood. It includes information about preparing 

for a flood, important actions after the disaster strikes, and information on 

financial assistance.

Checklists in this guide are not comprehensive and owners and operators 

may wish to contact other entities for additional information.

This guide does not replace existing federal or state regulations and is not to 

be used as a regulation. It also does not impose legally binding requirements. 

The word “should” as used in this guide, is intended solely to recommend or

suggest and does not connote a requirement.

For regulatory requirements regarding UST systems, refer to the requirements 

listed in 40 CFR 280, or the corresponding state regulations.

Introduction

Floods are caused by many different phenomenon including natural processes such as heavy 

rains, snow melt, earthquakes, tsunamis, or hurricanes. Likewise, failure of levees and dams or 

inadequate drainage in urban areas can also result in flooding. Floods are often unpredictable 

and the aftereffects can be damaging and costly to mitigate.

During floods, underground storage tank (UST) systems can become submerged or displaced by 

flood waters, leading to damaged UST systems or even releases of regulated substances into the 

environment. If UST facilities are damaged, they need to be returned to normal operation in the 

most expedient, safe, and environmentally responsible manner possible.

In the event of a flood, you - the local, state, or tribal underground storage tank authority - may 

respond to emergency calls from owners, operators, and other affected parties. The U.S. 

Environmental Protection Agency (EPA) developed this guide to help provide information to 

localities, states, and tribes when addressing relevant compliance challenges that may arise after 

a flood. This guide may not cover every possible situation you encounter.

This basic reference guide consolidates published and unpublished information from various 

federal, state, non-governmental, and UST industry resources. You may use the information in 

this guide to prepare for, prevent, or lessen the catastrophic effects and environmental harm that 

could occur as a result of flooded UST systems, as well as help return these UST systems to 

service as soon as possible. 
Underground Storage Tank Flood Guide 2

Effects Of Flooding On Underground Storage Tank Systems

A flood creates an elevated level of risk for environmental damage from UST systems. For 

example, UST systems may become displaced and release their contents into the environment, 

causing soil, surface water, and groundwater contamination. While there is little that can be 

done to prevent flooding, UST owners can take actions to minimize the damage potential that 

impacted USTs have on human health and the environment when flooding occurs.

The following impacts on UST systems could occur as a result of flooding:

• buoyancy

• erosion and scour

• product displacement

• electrical system damage

UST lifted by buoyant force

Buoyancy 

During a flood, an UST system surrounded by floodwaters or saturated soil is subjected to 

buoyant forces that could offset the restraint of backfill, pavement, or hold-down straps, causing

the tank to shift in the backfill from its location. If the UST is unanchored, it may lift out of the 

ground and float, resulting in a rupture or separation of the connecting pipes, releasing product 

into the environment. 

Erosion And Scour

Forces of rapidly moving water can cause soil erosion (resulting from soil above or around the 

UST being carried away by wind and floodwaters) and scour (resulting from the velocity of 

flowing water removing soil cover and supporting backfill material around the UST system). 

Exposing the system to stressors from flood water pressure or floating debris makes it even more 

vulnerable to being undermined or collapse. As a result of erosion and scour, underground 

piping can also shift and become detached from the UST, releasing product into the environment. 

. 
Underground Storage Tank Flood Guide 3

 Collapsed gasoline tank. Hurricane Katrina – 2005, Biloxi, MS

Product Displacement

During a flood, water or other debris can enter an UST through openings such as fill pipes, vent 

pipes, gaskets, loose fittings, covers, sumps, and damaged tank walls. As water and debris settle 

on the bottom of the UST, product will rise and float on top until it exits the tank through 

openings, releasing product to the environment. 

Electrical System Damage 

Extended contact with floodwaters may cause damage to electrical 

equipment associated with UST systems (such as automatic tank gauging 

systems, panel boxes, emergency shutoff switches, submersible turbine 

pumps, dispensers, motors, cathodic protection, etc.). 
Underground Storage Tank Flood Guide 4

What If An UST Is Located In A Flood Area?

Because of their locations in or near water or low-lying areas, some USTs are particularly 

vulnerable to the effects of flooding. Installation standards such as the Petroleum Equipment 

Institute’s (PEI) Recommended Practice 100 and the American Petroleum Institute’s (API) 

Recommended Practice 1615 contain information about proper anchoring of USTs. 

If there is reason to believe an UST is in a vulnerable location, owners and operators may use the 

following methods to help prevent USTs from floating during a rise in water levels:

• Increase the burial depth and/or amount of 

pavement above the UST. The extra weight of the 

backfill and pavement may be enough to keep the 

tank from floating. The burial depth should not 

exceed the manufacturer’s recommendation.

• Anchor the UST to counteract the buoyancy force 

exerted by saturated soil during a flood to prevent 

flotation by: 

 using deadmen anchors placed outside 

of the tank diameter along the sides of 

the UST, with hold-down straps 

attached. 

 

 Deadmen anchors and straps used to offset buoyancy

Soil conditions can 

dramatically affect 

buoyancy forces. 

Owners should 

consult with a 

knowledgeable 

professional who is 

familiar with the 

local soil conditions 

when designing 

anchors to counter 

buoyancy forces.
Underground Storage Tank Flood Guide 5

 adding

additional 

weight by using 

a concrete 

collar.

 Illustration of adding a concrete collar at the top of the tank to offset buoyancy

 using hold-down 

straps to securely 

attach the tank to 

a bottom holddown pad. 

 Illustration of hold-down pad installation under the UST to offset buoyancy

Owners and operators may also want to consider taking the following precautionary actions:

• Equip fuel lines below the flood elevation level with automatic shut-off valves. This 

will help prevent loss of fuel in case of line breaks or disconnects from the UST.

• Add an extension to the vent pipe if it appears the tank may be submerged in deep 

flood waters. If water enters the vent pipe, it will settle at the bottom of the tank, 

pushing product out.
Underground Storage Tank Flood Guide 6

Before A Flood, What Should Owners And Operators Do?

In order to prevent UST system displacement and prevent water from entering the system,

owners and operators should consider taking these precautions if there is a threat of flood.

• Turn off all electricity to the UST system including power to dispensers, pumps, 

turbines, automatic tank gauging (ATG) consoles, lighting, and any other system 

components. 

• Take product inventory and water level reading of all USTs to help account for 

possible product loss.

• Fill the tank to weigh down the tank so it will not 

float out of the ground. 

• Secure all openings on top of the tank and make 

sure fill caps are in good condition and fastened 

securely in place and locked. If fill caps are not 

tightened, tanks will fill with water and release

product. Empty or near-empty tanks may float up, 

destroying overlying concrete/asphalt and distribution 

lines, which can also release product.

• Make sure the seal on spill bucket plungers are 

operational so water cannot enter the tank.

• Close the shear valve on pressurized piping to prevent releases from product dispenser 

lines.

• Temporarily cap off the vent pipes to prevent water from entering the tank and 

displacing product.

• Place a dumpster, sand bags, or large containers full of sand or rock over the tank to 

reduce the chance of a tank floating out of the ground. 

 

Tank owners and 

operators should 

not fill tanks with 

water because 

they may incur 

additional costs 

for the disposal of 

contaminated 

water.
Underground Storage Tank Flood Guide 7

After A Flood, What Should Owners And Operators Do?

After a flood, regional and state UST program 

representatives may receive calls from UST owners and 

operators with questions concerning problems with tank 

systems; or affected parties may call the National Response 

Center (NRC), the federal government’s sole point of contact 

for reporting all hazardous substance and oil spills. The 

following practices may help owners and operators quickly 

and safely restart UST systems and bring them back into 

service. Flood of 1977

 Matewan/Tug Valley, West Virginia

If the UST has been in a flood, depending on the site-specific situation, owners and operators 

may take the following actions after the water has receded and local officials allow for re-entry:

• Make sure the power is off to any UST-related equipment (such as power to the 

dispensers, pumps, release detection equipment, and other devices).

• Determine if product leaked from the UST.

• Determine if water or debris entered the UST.

• After inspecting the electrical system, return power to the UST system.

• Check release detection system for proper operation. Perform release detection again, 

as soon as possible after the flood.

• Check all equipment including pumps, shear valves, fill pipes, and vent lines for proper 

operation.

• Clean and empty spill buckets and sumps, including those under the dispensers and 

above the tanks. Inspect the piping and fittings for damage and possible leaks.

• Perform an UST system tightness test to ensure integrity prior to adding product. 

• Test spill buckets and sumps to ensure they are tight.

• Test cathodic protection to ensure it is operating properly.

For information and checklists about USTs and floods from API, Delaware, Iowa, Louisiana, 

Minnesota, and Washington, see Appendices A and B.
Underground Storage Tank Flood Guide 8

Remind tank 

owners and 

operators to 

follow 

established state 

program 

environmental 

compliance 

guidelines for 

emergency 

response, 

cleanup, tank 

removal, waste 

disposal, and 

reinstallation.

What If A Tank Floats Out Of Its Excavation?

The tank may float out of its original backfill site if not adequately anchored. If this occurs, the 

following actions may be appropriate:

• Notify the appropriate authorities according to 

applicable policies, if there is any evidence of spilled 

product. 

• Notify the local fire department.

• Turn off any power in the vicinity of the tanks and 

piping, and immediately call the electric company if any 

power lines are down in the area.

• Rope off the area and keep people away from the 

affected area.

• Remove all contents of the tank.

• Perform initial leak mitigation and release reporting, if necessary.

• Obtain a contractor to dismantle any piping and/or dispensers, and remove the 

piping and tank properly.

 

 

 Tank floating out of ground, Rockaway River, NJ Iowa flood of 2008 
Underground Storage Tank Flood Guide 9

What If A Remediation System is Flooded?

Some UST facilities have an active soil and/or groundwater remediation system in place that 

floods can significantly affect. Owners and operators may take the following precautions to 

minimize damage to the system and safely bring it back into service:

Before a flood –

• Shut off power to the remediation system.

• Disconnect the wiring and piping to the trailer and remove from the apparent flood 

hazard area, if there are any portable equipment trailers.

• Cap and secure any monitoring, recovery, or injection wells to prevent floodwaters from 

entering the wells.

• Remove equipment from the building and store away from flood waters, if remediation 

equipment is located in a non-portable building.

• Close all control valves to isolate as much of the system as possible.

After a flood –

• Do not attempt to restart motors until an electrician checks the motors and/or controls 

for damage and presence of moisture or silt.

• Reconnect the trailer to the power and piping system, if equipment trailer was removed 

from the site.

• Return power to the remediation system after inspecting electrical system. A qualified 

professional should disinfect components and systems.

• Remove and discard system components that are contaminated with flood water and 

cannot be effectively cleaned and disinfected. Replace them with new components.

• Clear piping of water and/or silt that may have collected in the lines, if piping has been 

damaged or flood water enter the piping.

• Inspect monitoring wells for damage.

• Check the valves in the piping system for proper operation.

• Check to see if water and/or silt entered monitoring/extraction/injection wells.

• Notify the implementing agency of any damage that may have occurred.
Underground Storage Tank Flood Guide 10

Other Useful Information

Industry and states developed guides to assist owners and operators in 

evaluating flood impact and damage to UST systems. Although federal 

UST regulations do not require using these guides, excerpts from selected 

guides are available in Appendices A and B.

Note: Leak detection equipment must be operational as soon as 

practically possible; however, certain leak detection methods may not be viable. 

• Use daily inventory control and monthly reconciliation if electronic method of leak 

detection is not operating. EPA provides guidance books and log sheets for daily 

inventory control and monthly reconciliation at www.epa.gov/OUST/pubs/doing.htm

• Owners and operators should perform daily checks for water with water-finding paste for 

several days until the owner determines the system is tight. 

• Owners and operators should empty tank contents and stop using the tank if water checks 

indicate excessive water or daily inventory control shows loss of product. 

• Owners and operators should notify the appropriate implementing agency, as soon as 

possible.
Underground Storage Tank Flood Guide 11

If there is a confirmed release, 

visible free product, or a 

substantial threat of a release, 

tell the caller to contain the

leak and notify appropriate 

local and state authorities. If 

the release may reach, or has 

reached, surface water or 

shoreline, instruct the caller to 

contact the National 

Response Center at 800-424-

8802 or 202-267-2675 or 

submit an incident report via 

email to 

http://www.nrc.uscg.mil/nrchp

.html. Also, inform callers to 

notify the appropriate local or 

state emergency management 

authority. If a release is 

reported, the NRC will notify 

the appropriate designated 

federal on-scene coordinator 

(EPA for inland areas or Coast 

Guard for coastal areas). 

Incident Response

Natural disaster occurrences can damage UST system components, resulting in oil, petroleum, or 

hazardous substance releases into the environment. You may receive a call requesting 

information such as: Who do I call? My tank is leaking, what should I do? Is there guidance 

available for emergency cleanup? Is funding available for cleanups? etc. 

What Do I Do If I Get A Phone Call?

Individual owners and operators are 

primarily responsible for initial response 

and cleanup and are expected to be the 

first to handle most problems with 

existing resources, but in some cases 

local assistance may be available. If local 

response capabilities are overwhelmed, 

state and then regional resources may be

used. In Indian country, local and tribal

officials are the first responders, and EPA is available for further 

assistance. The federal government generally only becomes 

involved when local and state resources are overwhelmed, or 

when incidents occur in Indian country. 

Local, state, tribal, and federal agencies engage in environmental 

cleanup actions on a regular basis and will be involved in natural 

disaster response. Local Emergency Planning Committees 

(LEPCs) plan initial response actions for emergencies within 

their jurisdiction. They do not perform actual incident response, 

but attempt to identify potential hazards, find available 

resources, and write emergency plans. However, they are not 

available within every locality. For more information or to 

locate a specific LEPC, see http://yosemite.epa.gov/oswer/lepcdb.nsf/HomePage. Owners 

and operators may also contact a local emergency management office or fire department. 

Other Emergency Contacts

• State emergency response or specific state office of emergency management: 

http://www.fema.gov/about/contact/statedr.shtm

• State environmental agency: http://www.epa.gov/epahome/state.htm

• EPA regional emergency response management programs: 

http://www.epa.gov/OEM/content/regional.htm

• National Response System (NRS): http://www.epa.gov/oem/content/nrs/index.htm
Underground Storage Tank Flood Guide 12

To qualify for FEMA assistance, the 

site must be located in one of the 

Presidential declared disaster 

counties. 

After a Presidential declaration has 

been made, FEMA will designate the 

area eligible for assistance and 

announce the types of assistance 

available. 

Financial Assistance

• Many states have financial assurance programs and/or disaster trust funds that provide 

loans and grants to eligible owners and operators for corrective actions and bringing UST 

facilities back into operation, where applicable. State trust funds may reimburse 

responsible parties or third parties for corrective actions related to UST releases if certain 

prerequisites for coverage are met. 

• In an emergency, states may use Leaking Underground Storage Tank (LUST) Trust Fund 

money to conduct emergency responses, site assessments, or corrective actions. In nonemergency situations, states may use LUST Trust Fund money to conduct site 

assessments or corrective actions where the responsible party is unknown, unwilling, or 

unable to respond. 

UST system owners and operators should contact their financial responsibility or 

insurance provider to file a notice or claim and determine minimum requirements 

necessary for continuing coverage. Failure to do so could jeopardize coverage in the 

event of a subsequent release.

Other Types Of Financial Assistance Available To Owners And Operators 

Businesses may obtain financial assistance 

following disasters, including floods, from the 

Federal Emergency Management Agency 

(FEMA) and the U.S. Small Business 

Administration (SBA). 

FEMA Public Assistance Grant 

The objective of FEMA’s public assistance (PA) grant program is to provide assistance to state, 

tribal, and local governments as well as certain types of private nonprofit organizations. 

Through the PA program, FEMA provides supplemental federal disaster grant assistance for 

debris removal; emergency protective measures; and repair, replacement, or restoration of 

disaster-damaged, publicly owned facilities and the facilities of certain private non-profit 

organizations. The PA program also encourages protection of these damaged facilities from 

future events by providing assistance for hazard mitigation measures during the recovery 

process.

The federal share of assistance is not less than 75 percent of the eligible cost for emergency 

measures and permanent restoration. The grantee (usually a state) determines how the nonfederal share (up to 25 percent) is split with the subgrantees (eligible applicants).
Underground Storage Tank Flood Guide 13

Additional State Assistance

During some disasters, states may also request that FEMA assign and fund EPA to 

provide direct assistance with oil and hazardous materials cleanup. This is 

accomplished under the Oil and Hazardous Materials Response section (i.e., Emergency 

Support Function 10 [ESF-10] of the National Response Framework). Facility owners do 

not request ESF-10 assistance directly from FEMA or EPA. Only a state can request 

assistance under this mechanism, and FEMA may require a state to contribute a 

percentage of the ESF-10 costs. For more information on the National Response 

Framework and ESF-10, see FEMA’s web page: http://www.fema.gov/emergency/nrf/.

FEMA Disaster Assistance Process

FEMA developed sequential steps owners and operators, as applicants, should follow to obtain 

prompt disaster assistance. If FEMA assistance is 

needed:

1- Applicants need to register with FEMA for an 

identification number. Applicants may register on 

FEMA’s website 

www.fema.gov/assistance/index.shtm or by phone by 

calling 800-621-FEMA (3362). Persons with speech 

or hearing disabilities may call TTY at 800-462-7585. 

2- Once a FEMA identification number is secured, 

applicants may file with SBA by downloading an 

application from SBA’s website

http://www.sba.gov/category/navigationstructure/starting-managing-business/startingbusiness/forms, or visiting a SBA local disaster 

office. For more information, contact SBA Disaster 

Assistance Customer Service Center at 800-659-2955 

or disastercustomerservice@sba.gov

www.sba.gov/services/disasterassistance.

3- Applicants should send the completed application 

to SBA. Applicants are encouraged to go to a local 

disaster recovery center (DRC) for assistance 

completing the SBA application. Some DRC 

locations will have business recovery centers with staff on the ground to help with paperwork 

and questions. In addition, applicants may also go to one of the existing small business 

development centers.

SBA Loans

Through its Office of Disaster 

Assistance, the SBA provides lowinterest loans for damage to 

businesses that are not fully 

covered by insurance. After a 

declared disaster, SBA will deploy 

loan officers to SBA local disaster 

offices to provide face-to-face 

service for disaster victims. Any 

business that is located in a 

declared disaster area and has 

incurred damage during the 

disaster may apply for a loan to 

help repair or replace damaged 

property to its pre-disaster 

condition. 

Physical disaster loans are for 

permanent rebuilding and 

replacement of uninsured or 

underinsured disaster-damaged 

privately-owned real and/or 

personal property. SBA’s physical 

disaster loans are available to 

businesses of all sizes.
Underground Storage Tank Flood Guide 14

References

EPA compiled many of the recommendations contained in this guide from other federal, state, 

and industry organizations. Listed below are publications from other organizations that EPA 

used to prepare this guide. They may be helpful to owners and operators when inspecting, 

installing, repairing, or replacing UST systems that are impacted by flooding. 

• American Petroleum Institute. Options for Consideration: Opening a Service Station 

after Flooding, 2005

• American Petroleum Institute. API Recommended Practice 1615 (1996, 5th ed), 

Installation of Underground Petroleum Storage Systems

• Canadian Petroleum Products Institute. Contingency planning for flood related 

emergencies at retail and wholesale petroleum facilities (2001). Retrieved from

http://www.cppi.ca/pdf/FloodProcedures.pdf 

• Delaware Department of Natural Resources and Environmental Control (2006). 

Salvageable Flooded Dispensing Facilities with USTs: Recommended Inspection and 

Integrity Assessment Protocol for Placing Flooded Facilities Back into Service. 

Retrieved from 

http://www.dnrec.state.de.us/dnrec2000/Divisions/AWM/ust/Download/pdf/Flooded%20

USTs.pdf

• Federal Emergency Management Agency. Principles and Practices for the Design and 

Construction of Flood Resistant Building Utility Systems (1999). Retrieved from 

http://www.fema.gov/hazard/flood/pubs/pbuffd.shtm

• Federal Emergency Management Agency – NRF Resource Center. Retrieved from 

http://www.fema.gov/emergency/nrf/aboutNRF.htm

• Federal Emergency Management Agency – State Offices and Agencies of Emergency 

Management. Retrieved from http://www.fema.gov/about/contact/statedr.shtm

• Iowa Department of Natural Resources (2008). Floods & Submerged USTs: Procedure 

to Return Tanks to Service. Retrieved from

http://www.iowadnr.gov/land/ust/documents/ustflood608.html

• Louisiana Department of Environmental Quality (2005). Plan For Evaluating 

Underground Storage Tank Sites Impacted By Hurricane Katrina. Retrieved from 

http://www.deq.louisiana.gov/portal/portals/0/news/pdf/UST_Cover_Letter_and_Emerge

ncy_Declaration.pdf

• Louisiana Department of Environmental Quality (2008). Plan For Evaluating 

Underground Storage Tank Sites Impacted By Hurricane Gustav. Retrieved from 

http://www.deq.state.la.us/portal/Portals/0/UndergroundStorageTank/hurricane%20packe

t.pdf
Underground Storage Tank Flood Guide 15

• Minnesota Pollution Control Agency (2006). Preparing Your Underground Storage Tank 

For A Flood. Retrieved from http://www.pca.state.mn.us/publications/t-u1-16.pdf

• National Fire Protection Association. NFPA 30 Flammable and Combustible Liquids 

Code, 2003

• National Fire Protection Association. NFPA 30A Code for Motor Fuel Dispensing 

Facilities and Repair Garages, 2008

• National Response Center – On-line reporting tool. Retrieved from 

http://www.nrc.uscg.mil/nrchp.html

• Petroleum Equipment Institute. RP900 Recommended Practices for the Inspection and 

Maintenance of UST Systems

• Petroleum Equipment Institute. RP100 Recommended Practices for Installation of 

Underground Liquid Storage Systems

• Petroleum Equipment Institute. RP500 Recommended Practices for Inspection and 

Maintenance of Motor Fuel Dispensing Equipment

• Siciliano, J. (2007). Mitigation funding in the FEMA Public Assistance Program. 

Adjusters International, Inc. Disaster Recovery Today (9). Retrieved from 

http://www.adjustersinternational.com/DisasterRecoveryToday/?CFID=1274911&CFTO

KEN=17903072

• U.S. Environmental Protection Agency, Office of Underground Storage Tanks - List of 

operation and maintenance resources: http://www.epa.gov/oust/ustsystm/tanko&m.htm

• U.S. Environmental Protection Agency, Office of Emergency Management – National 

Response Center. Retrieved from http://www.epa.gov/oem/content/partners/nrsnrc.htm

• U.S. Environmental Protection Agency, Office of Emergency Management – Local 

Emergency Planning Requirements. Retrieved from 

http://www.epa.gov/oem/content/epcra/epcra_plan.htm

• U.S. Environmental Protection Agency, Office of Emergency Management – Regional 

Emergency Management Programs. Retrieved from 

http://www.epa.gov/OEM/content/regional.htm

• Washington State Department of Ecology (2009). Focus on Flooding Prevention. 

Retrieved from http://www.ecy.wa.gov/biblio/0909190.html
Underground Storage Tank Flood Guide 16

Appendix A – API Checklist

Options for Consideration: Opening a Service Station after Flooding

This list is not intended to be a complete checklist. In general, after severe flooding, serious consideration should be 

given to having a system test similar to a test done for a new installation completed by a competent technician. All 

suggestions may not necessarily be applicable to every station or situation and therefore may not be required.

DOs:

UST

• Check electrical system for continuity and shorts (pumps, turbines, dispensers, emergency shutoff, panel box, etc.) 

• Check Critical safety devices (e.g., shear valves, stop switches, isolation relays on dispensers, etc.)

• Check tank bottoms for water and debris (due to surface infiltration) *

• Check tightness testing of tanks

• Check deflection of fiberglass tanks. If deflection is greater than manufacturer’s specification (general guideline is 

2%), call the manufacturer for instruction

• Check cathodic protection system to ensure it is connected and operational

• Flush dispensers and entire UST system with nitrogen (or some other inert gas)

• If tanks shifted and problems are found, repair them according to appropriate industry standards (API 1615 and 

NFPA 30 and 30A) and regulations (40 CFR 280)

• Follow proper procedures for calibrating tank inventory charts (SIR tank angle)

Dispenser/Lines

• Check vents for blockage and proper operation

• Eliminate water in dispenser sumps, pans, tank sumps, etc. (Sump water should be removed by an authorized 

and/or state licensed waste hauler to be taken to an appropriate treatment facility.)

• Check vent and vapor lines (Stage II) for movement and cracking

• Check all Stage II system equipment (e.g., filters, screens, etc., for the presence of dirt, mud, etc.) 

• Check dispenser filters and submersible check-valve screens for plugging with dirt or mud

• Check tightness testing of piping

Monitoring Equipment

• Check pressure transducers on product line leak detectors (ensure no water infiltration)

• Check monitoring wells for contamination

• Check with vendors for recommendations on proving equipment 

• Ensure that communication system working related to any remote monitoring (GVR and the FMS)

• Ensure security systems are in place (cameras and alarm functions)

Miscellaneous

• Treat and dispose of any hazardous waste (i.e., gasoline contaminated water or water contaminated gasoline) 

according to applicable federal (i.e., Resource Conservation and Recovery Act and its attendant regulations) and state 

laws and regulations

• Ensure payment process is functioning

• Ensure adequate lighting on forecourt

• Clear all stormwater drains of debris

• Notify authorities as appropriate

DON’Ts:

• DO NOT receive new product until system integrity is proven

• DO NOT assume everything is okay because water didn’t actually flood over station. The water table could have 

risen and caused problems

* Stick tank or read automatic tank gauge system to determine whether water has entered the UST. If using ethanol 

as an oxygenate in your fuels, determine whether ETOH phase-shift has occurred (use an ethanol-water detecting 

paste). If water is in the tank and ethanol is not an oxygenate, have the water pumped from your UST by a licensed 

and approved waste hauler to be taken to an appropriate treatment facility. If ethanol is used as an oxygenate and a 

phase-shift has occurred, which could happen with 5-6 inches of water) consider pumping the UST completely. Again 

have the water pumped from your UST by a licensed and approved waste hauler to be taken to an appropriate 

treatment facility. 
Underground Storage Tank Flood Guide 17

Appendix B – Selected State Information On Returning Flood 

Impacted USTs To Service

Delaware Department of Natural Resources recommended guidance on UST inspection and assessment after a 

flood

Salvageable Flooded Dispensing Facilities with USTs: Recommended Inspection 

and Integrity Assessment Protocol for Placing Flooded Facilities Back into Service 

1 Render the facility in a safe condition by turning off all power. 

2 Inspect for obvious damage to the dispensing facility. Cover pad movement is an indicator of 

possible tank movement. If there is an indication of cover pad movement, especially if the cover pad 

is needed to prevent floatation, remove cover pad, inspect tank and replace if tank is O.K. 

3 Any evidence of tank, vent or line movement (horizontal or vertical) will necessitate 

replacement of affected components. If the tank manufacturer will recertify the tank after removal, it 

may be reinstalled. 

4 Tanks and all lines need to be checked for water contamination and drained or pumped dry, 

cleaned and sanitized where necessary. 

5 Interstitial spaces of tanks and lines need to be drained, flushed and sanitized where possible. 

Blockage of interstitial spaces will render leak detection useless. Depending on the level of residual 

contamination at the facility, certain leak detection methods may no longer be viable. Be prepared to 

update leak detection equipment. 

6 Salvageable dispensers shall be flushed clean and all filters etc. replaced. 

7 Submerged dispensers will have to be replaced. This includes the hanging hardware. 

8 All facility sumps and spill buckets need to be pumped dry, cleaned and sanitized. Replace 

sump lid gaskets if applicable. If sump lids are missing, replace with new water tight lids. Test for 

tightness and replace sumps and spill buckets that fail tightness testing. 

9 Shear valves and related safety equipment may be salvaged if they can be cleaned and 

lubricated with corrosion preventative. Some will still have to be replaced. 

10 Sump sensors submerged for a prolonged period of time will need to be replaced. 
Underground Storage Tank Flood Guide 18

11 In-tank pumps, ATG probes, overfill devices, automatic line leak detectors, fill and vapor 

dust caps etc. are probably O.K. Assess their condition after cleaning and replace as necessary. 

12 Non water-tight conduits will be a problem. Drain and sanitize wherever possible. Check 

wiring for shorts. Consider sealing conduits where possible. 

13 Submerged ATG consoles and any associated electronics will need to be replaced. If not 

submersed, have certified technician perform a programming and operability check. 

14 Submerged CP rectifiers and associated aboveground equipment protecting tanks and/or lines

will have to be replaced. If not submersed, have a NACE certified professional perform an 

operability check of equipment. Inspect CP lines in saw cuts for damage and replace as necessary. If 

CP systems are out of service for an extended period of time, perform integrity assessment of 

affected component before placing CP system back into service. A NACE certified professional will 

be helpful in assessing the CP system. 

15 Check accessible fittings, valves and miscellaneous piping for damage and corrosion. Clean 

and replace as necessary. 

16 Pressure test tanks, lines and interstitial spaces. Assess interstitial spaces for blockages, 

especially if used for leak detection. 

17 Perform blockage tests on all lines prior to start up. 

18 To assess tightness of vapor spaces, perform pressure decay test of the system. 

19 Document all inspection, repair and assessment activities at each flooded facility in 

accordance with Tank Management Branch requirements. 

20 Check with the Tank Management Branch to verify what Financial Responsibility items that 

need to be addressed prior to placing the facility back into service. 
Underground Storage Tank Flood Guide 19

Excerpt from Iowa Department of Natural Resources guidance for UST system evaluation 

Before flooded UST systems are returned to operation, they must be evaluated by an Iowa licensed 

installer, installation inspector or compliance inspector to determine the extent of damage or whether they 

are suitable to receive product. The owner or operator must document to the DNR that the system has 

been inspected and certified as safe to return to operation. A list of Iowa licensed installers can be found 

at DNR’s UST Section website: http://www.iowadnr.com/land/ust/ustinstall.html. 

The evaluation of UST status should begin as soon as conditions and officials allow flood area re-entry. 

This policy assumes that there is a reasonable likelihood that a release of product may have occurred if 

an UST system has been submerged or affected by flood waters. The following procedure is intended to, 

in part, comply with the "system check" requirements whenever there is a suspected release as provided 

in agency rule 567 Iowa Administrative Code 135.6. This policy further assumes that damage may have 

occurred such that inspection, product removal and repairs may need to be undertaken. All submerged 

and flood affected USTs must follow the proceeding evaluation before start up. 

1. Measure for water in the tank bottoms with your ATG system or by using a gauge stick (capable 

of measuring the level of product to within 1/8 inch) and water finding paste. If you have over an 

inch of water you will need to remove it. No water is acceptable for tanks containing an ethanol 

blend as the water will be absorbed by the ethanol and create fuel quality problems. Contact a 

hazardous waste management company (see last page for a list) for more information about 

removing water/ethanol mix from ethanol blended tanks. Fuels sold in retail markets must meet 

strict ASTM standards; make sure your fuel quality is not compromised. Fine silts are present in 

flood waters and may contaminate the fuel. The fine silts will need to be removed if present. 

Fuels will have to be removed if the UST system is found to be damaged during the evaluation. 

2. Before returning to operation, all flooded UST systems must conduct tank and line tightness 

testing (0.1 gph). Tightness testing may be conducted using an Automatic Tank Gauging (ATG) 

system or a third party tightness tester. Tanks with secondary containment (double wall) may use 

interstitial monitoring in lieu of tightness testing. Tanks with confirmed “Fail” results must be 

emptied. 

3. If water entered interstitial spaces of tanks and product lines, they must be drained and flushed 

where possible. Tanks with brine, vacuum or interstitial sensors may be returned to service if the 

levels are normal. 

4. Empty and clean all containment sumps, spill buckets and dispenser pans. If there is no 

petroleum sheen on the water, you should be able to empty it onto the concrete where it can 

evaporate. Water with a petroleum sheen or floating product in a containment sump must be 

investigated for a release. The water and petroleum must be removed and properly disposed by 

a hazardous waste management company (a list is provided with this guidance memo). Do not 

discharge contaminated water to a streets, storm sewers, ditches or sumps. Do not operate 

pumps and dispensers if they continue to fill with flood waters as there is chance water could 

enter the fueling system and damage components.

5. Submerged dispensers may have to be replaced or repaired if possible. Any submerged suction 

system will have damaged motors and pumps. Check hanging hardware for damage. 

6. Check sump lid gaskets. After initial cleaning and drying make sure sumps, dispenser pans and 

spill buckets are liquid tight and prevent water ingress.

7. If you have more than one inch of water in a diesel or gasoline tank (non-ethanol blend), have it 

removed by a hazardous waste management company. More than an inch of water at the bottom 

of the tank can contaminate fuel systems in vehicles. Hazardous waste management companies 

can remove the water and leave the product in the tank. 

8. Check the deflection of fiberglass tanks to make sure they meet the manufacturer’s specification. 
Underground Storage Tank Flood Guide 20

9. Determine whether the tank moved or shifted. If problems are found, repair according to 

manufacturer’s instructions and appropriate industry standards and regulations. These tanks 

must not receive fuel until that are deemed safe and tight. 

10. Check vents for movement, cracking, blockage and proper operation. This is a common area for 

water ingress and damage from flooding. 

11. Check dispenser filters and submersible check-valve screens for plugging with dirt or mud.

12. Check critical safety devices (e.g., emergency power off controls, line leak detectors, air 

compressor pressure limiters, shear valves, stop switches, isolation relays on dispensers, etc.). 

Shear valves may be salvaged if they can be cleaned and lubricated with corrosion preventative. 

Some may still have to be replaced. 

13. Sump sensors may need to be replaced after emergency conditions cease.

14. Submersible turbine pumps, ATG probes, overfill devices, ALLDs and all caps at the top of the 

tanks must be assessed for damage and replaced if necessary. 

15. After flooding has abated, submerged CP systems must be assessed by a NACE or Steel Tank 

Institute certified cathodic protection professional. Submerged rectifiers may have to be replaced, 

if not submerged they must be checked for proper operation. Inspect CP wiring in saw cuts for 

damage and replacement if necessary. 

16. Make sure the electrical system for the ATG, fueling and corrosion prevention systems is checked 

for shorts and continuity before restoring power. 

17. All electrical junction boxes and conduit should be inspected for the presence of water and dried 

or vacuumed and for the presence of electrical shorts or opens. Open all dispenser panels to 

inspect and dry out. 

18. Make sure tank management tags are present on the fill port. If missing contact the numbers 

listed in this guidance. 

The following steps should be taken after your UST system is evaluated as safe and operational: 

1. Check daily for the presence of water (with water finding paste) to ensure the system is tight. If 

these water checks indicate excessive water or you are showing loss of product on daily 

inventory, the tanks should be emptied of product and use of the tanks should discontinue. Such 

a condition must be reported to DNR (515.281.8879 or 515.281.8779) no later than 24 hours after 

discovery. See rule 567 IAC 135.6 .

2. Use daily inventory control and monthly reconciliation if your current electronic method of leak 

detection is not operating. Guidance books and log sheets for daily inventory control and monthly 

reconciliation are provided on EPA’s website: http://www.epa.gov/OUST/pubs/doing.htm.
Underground Storage Tank Flood Guide 21

Excerpt from Louisiana Department of Environmental Quality plan for evaluating underground storage tank 

sites impacted by Hurricanes Gustav and Katrina

GENERAL INFORMATION 

UST Owners/Operators will be responsible for evaluating underground storage tank 

systems to determine if they are suitable for receiving product. Flooded systems that are 

determined to be suitable for receiving product may be put back into service and should 

have an integrity test performed as soon as contractors and services become available to 

perform the testing and no later than six months after product was first placed into the tank 

after flooding. If the tank inspection outlined below (or subsequent monitoring of the tank), 

indicates that the system has been comprised; the system should be taken out of 

service and repaired or replaced as necessary and an integrity test performed prior to 

again putting the system into operation. 

General Evaluation Protocol for Contractors 

No equipment should be turned on prior to examination. Check all electrical panels and 

make sure they are clean and dry. All equipment related to electric power service should be 

inspected and any necessary repairs should be made prior to power restoration. This 

includes all fueling systems, leak-detection devices and corrosion prevention (impressed 

current) equipment. The electrical system should be checked for continuity and shorts 

(pumps, turbines, dispensers, ATG consoles, emergency shutoff, panel box, etc.) 

Specifically, all electrical junction boxes and dispenser heads should be opened, inspected 

and dried if necessary. Conduits should be inspected for the presence of water, insulation 

damage, shorts or opens. Conduits exhibiting water should be dried or vacuumed as 

appropriate and all defective wiring should be replaced. To apply electrical power to a UST 

system before conducting basic examination could be extremely dangerous. 

Submerged pumps and dispensers should not be operated if there is the possibility of water 

entering into the system as pumping water may damage hydraulic components. 

Technical Protocol for Contractors 

These protocols should be followed to place tanks back into service: 

1. Stick tanks using water finding paste or read automatic tank gauge system, if 

operable, to determine whether water has entered the UST. 

2. Flooded or water impacted tanks and all lines may need to be drained of water 

and dirt/mud or perhaps pumped dry and cleaned as conditions warrant. 

Liquids removed must be properly handled and disposed. 

3. Interstitial spaces of tanks and lines of double walled systems, if flood-impacted, 

will need to be drained and flushed where possible. Blockage of interstitial 

spaces will render leak detection useless. Depending on the level of residual 

contamination at the facility, certain leak detection methods may no longer be 

viable. Tanks with brine or vacuum interstitial sensors may be returned to 

service if brine or vacuum levels are normal. Be prepared to update damaged 

leak detection equipment after emergency conditions are abated. 
Underground Storage Tank Flood Guide 22

4. All facility sumps, pans, and spill buckets need to be pumped dry and cleaned. 

Replace sump lid gaskets if applicable. If sump lids are missing, replace with 

new water tight lids. Replace sumps and spill buckets that fail to prevent 

water intrusion after initial cleaning and drying. 

5. Check tank bottoms for water and debris. Remove and dispose as appropriate 

(see item #2 above). 

6. Check deflection of fiberglass tanks. If deflection is greater than manufacturer’s 

specification (general guideline is 2%) call the manufacturer for instruction. 

7. If tanks shifted and problems are found, repair or replace them according to 

manufacturer’s instructions and appropriate industry standards and 

regulations. Obviously, these systems should be shut down and not 

receive fuel until they are deemed safe for reuse (tightness tested). 

8. Check vents for movement, cracking, blockage and proper operation. 

9. Check dispenser filters and submersible check-valve screens for plugging with dirt 

or mud. 

10. Flush dispensers and UST system if necessary. Collect fluids for proper 

disposal. 

11. Check critical safety devices (e.g., emergency power off controls, line leak 

detectors, air compressor pressure limiters, shear valves, stop switches, 

isolation relays on dispensers, etc.) Shear valves may be salvaged if they can 

be cleaned and lubricated with corrosion preventative. Some will still have to 

be replaced. 

12. Sump sensors may need to be replaced after emergency conditions cease. 

13. In-tank pumps, Automatic Tank Gauge (ATG) probes, overfill devices, automatic 

line leak detectors, fill and vapor dust caps, etc. should be assessed. Assess 

their condition after cleaning and replace as necessary. 

14. ATG consoles and any associated electronics that are not submerged, should 

have a programming and operability check performed by a certified technician 

after emergency conditions cease. 

15. After emergency conditions are abated, submerged Corrosion Protection (CP) 

rectifiers and associated aboveground equipment protecting tanks and/or 

lines may have to be replaced. If not submersed have a National Association 

of Corrosion Engineers (NACE) certified professional perform an operability 

check of the equipment. Inspect CP lines in saw cuts for damage and replace 

as necessary. If CP systems are out of service for an extended period of time 

perform integrity assessment of affected component before placing CP 

system back into service. A NACE certified professional will be helpful 

assessing the CP system. 

16. Check accessible fittings, valves and miscellaneous piping for damage and 

corrosion. Clean and replace as necessary. 

17. Document all inspection, assessment and repair activities at each UST system 

site. Provide this information to the LDEQ in stand-alone report format within 

90 days of initiation of operations of that UST facility. 

18. Submerged dispensers will have to be replaced or repaired as necessary. This 

includes the hanging hardware. Any suction system dispensers will probably 

have flood impacted motors and pumps and may need complete 

replacement. 
Underground Storage Tank Flood Guide 23

General Protocol Upon Resumption of Service: 

Depending on the level of residual contamination at the facility, certain leak detection 

methods may no longer be viable. Daily inventory control (with strict record keeping) may be 

the short-term leak detection method by necessity. Daily checks for water with water-finding 

paste should be done for several days until it has been determined that the system is tight. 

If these daily water checks indicate excessive water or the daily inventory control shows 

loss of product, the tanks should be emptied of product and use of the tanks should 

cease. Notification of these conditions should be made to the LDEQ UST hotline (225) 219-

3406) as soon as practical. 

Post Start-Up Protocol for Contractors 

This protocol should be followed once flood-impacted tanks have been placed back into 

service and emergency response and restoration have been completed or as otherwise 

directed by LDEQ: 

Precision tightness test tanks, lines and interstitial spaces (after emergency conditions 

abate). Assess interstitial spaces for blockages, especially if used for leak detection. 

Decisions regarding replacement of tanks and lines should be made based on outcome of 

these tests. LDEQ field staff should be consulted on these decisions whenever possible. 

Cathodic protection systems should be checked to make sure they are connected and 

operational. 

These actions are being delayed in an effort to expedite fuel delivery capabilities and due to 

unavailability of sufficient contractors to perform the otherwise required work in a timely 

manner. All leak detection equipment must be put back into operation as soon as practically 

possible or as directed by the LDEQ after the emergency has abated. 

Other General Provisions for Owner/Operators and Contractors: 

At flood-impacted sites, facilities will be allowed to salvage useable fuel in USTs by 

checking fuel for water and allow salvage of useable fuel. If flood water covered vent lines, 

displacement of fuel would have occurred and large volumes of water may exist in the 

affected USTs and require proper storage/disposal. This water should not be discharged to 

areas such as streets, storm drains, sumps and ditches that are not permitted to receive 

these liquids. 

Requirements for remediation of contaminated groundwater via approved corrective action 

plans in place prior to the Hurricane are suspended at UST sites in the parishes of 

Jefferson, Orleans, Plaquemines and St. Bernard unless otherwise directed by the LDEQ. 

However, LDEQ may require systems remediating free phased product to continue pumping 

operations. 

Sites which have not experienced impacts from the Hurricane shall continue with routine 

remedial efforts and reporting (Unless RAC/consulting firm handling the remediation has 

been affected and displaced by the storm). 

All facilities in which remedial efforts are temporarily suspended or delayed must provide 

notice to the LDEQ UST hotline (225) 219-3406 and provide written documentation as 

directed. 
Underground Storage Tank Flood Guide 24

EVALUATION SCHEDULE 

The evaluation of UST status should be initiated as soon as conditions allow flood area reentry. Further testing will be performed once emergency conditions and major restoration 

efforts are complete and when sufficient contractors are available to perform the work. This 

further testing should be performed no later than six months after product was first placed 

into the tank after flooding.
Underground Storage Tank Flood Guide 25

Minnesota Pollution Control Agency guidance on preparing an UST before a flood
Underground Storage Tank Flood Guide 26
Underground Storage Tank Flood Guide 27

Washington State Department of Ecology guidance on flood prevention for USTs in high risk areas
Underground Storage Tank Flood Guide 28
Underground Storage Tank Flood Guide 29
Underground Storage Tank Flood Guide 30

United States Solid Waste And EPA 510-R-10-002

Environmental Emergency Response November 2010

Protection Agency 5401P www.epa.gov/oust/