oEPA

Underground Storage Tank Owners and Operators
Compliance Assistance Fact Sheet

UST Spill and Overfill Prevention

This document provides compliance tips for owners and operators of USTs regulated by the U.S.
Environmental Protection Agency (i.e., USTs in Indian country). It does not replace the federal UST
regulation. Additional information can be found at eDa.aov/ust.

EMERGENCIES
SEPA

Report oil or
chemical spills at:
800-424-8802

Repeated small releases can cause big environmental problems. So, every UST that is filled with more than 25
gallons of product needs spill and overfill prevention.

SPILL PREVENTION WITH SPILL BUCKETS. Spill buckets attached to USTs
temporarily contain small product spills during delivery. However, improper spill
bucket maintenance could lead to soil and groundwatercontamination. Follow these
tips to keep your spill buckets in good working order and to reduce risks.

¦	Be vigilant before and after product delivery. Inspect spill buckets before and immediately after product
delivery. Remove any spilled product immediately.

¦	Keep your spill buckets clean and dry. Accumulated debris or liquid in the spill bucket reduces its capacity
and ability to contain product. Inspect spill buckets after weather events like rains or snow melts. Empty
them immediately and properly dispose of the contents.

¦	Repair or replace damaged parts.

o Replace damaged gaskets and seals. Damaged seals and gaskets can result in non-tight spill buckets.
Inspect your spill bucket every 30 days during walkthrough inspection. Inspect all seals, including
around the fill riser, for any cracks, damage, or holes. Replace or repair as needed.

o Repair or replace damaged spill buckets, lids, and drain valves. Damaged, cracked, or corroded
spill buckets are not liquid-tight and will not contain spilled product. A damaged, missing, or poorly
fitting spill bucket lid may allow water and debris to collect in the spill bucket and enter the tank

¦	Think long-term. At least every three years, your singled-walled spill bucket must be tested for tightness.
For double-walled spill buckets, check for a leak in the interstitial area. Inspect for damage, corrosion,
deformation. Repair or replace if necessary.

¦	Get help if you need it. If you are unsure about yourspill bucket tightness, have a qualified service technician
test them for leaks.

For additional information on requirements for managing your spill bucket, see EPA's Must For USTs, available
online at epa.gov/ust/musts-usts.

[Type here]

EPA 510-F-24-006
July 2024


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Underground Storage Tank Owners and Operators
Compliance Assistance Fact Sheet

UST Spill and Overfill Prevention

Overfill prevention equipment is installed inside your tank to
stop or reduce product flow and to alert the delivery person
before the tank becomes full. If a tank is overfilled, product could
be forced through the vent line and other loose tank fittings,
potentially resulting in a release into the environment. Inspect
your overfill prevention equipment every three years to make
sure it is working properly.

¦	Overfill alarms let the delivery person know that product is reaching a certain level in the tank. They give
the delivery person time to shut off product flow.

O Alarms must be located where the delivery person can easily see or hear them.

O If you hear the alarm, make sure the delivery person has stopped the flow of fuel to the tank.
O Inspect the automatic shutoff device to make sure it has not been tampered with, disabled, or
removed from the fill pipe and there are no obstructions in the drop tube. A disabled automatic
shutoff prevents the valve from closing to prevent an overfill.

¦	Ball float valves slow product flow by preventing vapors from leaving the tank when product reaches a
certain level. This alerts the driver to stop the delivery. The top of the tank must be tight during deliveries
so that vapors cannot escape.

O Have a qualified UST contractor check to make sure the ball float operates properly and moves freely,

the cage is intact, and the ball float air hole is not plugged.

O Note: Ball floats may be used on tanks installed on or before 10/13/2015 if they operate properly.
Ball float valves may not be used when overfill prevention is installed or replaced.

Watch product deliveries and transfers.

¦	Pay close attention before, during, and after product delivery to help the delivery person avoid overfilling.

¦	Immediately report spills to your implementing agency. In Indian Country, this will be the EPA regional
office. Find regional contacts at: https://www.epa.gov/ust/underground-storage-tank-ust-regional-
contacts. In the states, it will be your state implementing agency. Find state contacts at:

https://www.epa.gov/ust/underground-storage-tank-ust-state-contacts.

Order the right amount of product Order the amount that will fill the tank to 90%. To determine the maximum
amount to order, multiply the tank capacity by 90 then subtract the amount of product currently in tank.

For inspection guidelines, checklists, and tips for overfill prevention, see EPA's Operating And Maintaining Underground
Storage Tank Systems: Practical Help And Checklists, available online at eDa.aov/ust/oDeratina-and-maintainina-
underaround-storaae-tank-svstems-Dractical-help-and-checklists.

[Type here]

EPA 510-F-24-006
July 2024

SEPA

OVERFILL PREVENTION

Overfill alarm	Automatic shutoff Flow restrictor

device	(ball float valve)

(flapper valve)


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