Petroleum Storage Tanks - Spill and Overfill Prevention

Why You Need Spill and Overfill Prevention Equipment

When filling an underground storage tank (UST), spill and overfill prevention equipment helps prevent releases to the environment. Without this equipment, overfills and spills can result in significant cleanup costs and lost product from your UST system.

With few exceptions, all UST systems must have spill and overfill prevention equipment.

Exceptions include:

• Facilities that do not exceed 25 gallons per transfer.
• UST systems equipped with alternative equipment that we have reviewed and approved.

Aboveground storage tanks typically do not need spill and overfill prevention equipment but may have requirements if subject to the Spill Prevention, Control, and Countermeasures (SPCC) regulation.

• See EPA’s SPCC Applicability webpage for more information.

Equipment Requirements

Read our PST Spill and Overfill Prevention and Control module (RG-475e) of the PST Super Guide (RG-475) for equipment requirements.

• See EPA’s guide to Inspecting and Maintaining Sumps and Spill Buckets for more help.

You may also need to meet requirements under EPA’s SPCC regulation if your total underground storage capacity is greater than 42,000 gallons.

Inspection Requirements

You must inspect spill and overfill prevention equipment every 30 days, plus periodic testing every three years. Containment sumps must be inspected every year.

30-Day Walkthrough Inspections

Applicable to spill prevention equipment. Inspect the equipment every 30 days to make sure it is in good working condition. Keep a logbook with dates of inspections, any results, and names of inspectors.

During this inspection:

• Remove any liquid and debris within 96 hours and properly dispose of it.
• Make sure fill pipes do not have obstructions and the cap fits securely.
• If there is double-walled spill prevention, check for leaks in the interstitial area.

Periodic Integrity Testing

Spill Prevention Equipment and Containment Sumps Used for Interstitial Monitoring:

Single-walled equipment and sumps must be tested at least once every three years to ensure the equipment is liquid tight by using vacuum, pressure, or liquid testing. Testing must be done using one of the following:

• manufacturer guidelines
• accredited lab testing procedures
• Petroleum Equipment Institute's RP-1200 testing procedures (available for purchase online )

If the spill prevention equipment and containment sumps are double-walled, wall integrity can be evaluated during the 30-day walkthrough inspections instead of doing the 3-year test. Keep records showing the equipment is double-walled and inspected every 30 days.

Overfill Prevention Equipment:

Overfill prevention equipment must be inspected at least once every three years.

During the inspection

• Check the equipment is set to activate at the correct level.
• Confirm equipment will activate when a regulated substance reaches that level.

Testing must be done according to manufacturer requirements or a code of practice developed by a nationally recognized association.

Annual Walkthrough Inspections

Inspect all sumps every year. During an annual inspection, check for damage, leaks, or evidence of potential releases. 

Other annual inspection requirements depend on:

• If your USTs were built before or after January 1, 2009.
• You used for interstitial monitoring.
• Whether the sumps has containment or not.

For sumps used for interstitial monitoring and USTs built after January 1, 2009: ensure any sump secondary containment is liquid tight and check for leaks in the interstitial area.

• Remove any liquid and debris within 96 hours and properly dispose of it.

For single-walled sumps not used for interstitial monitoring and USTs built before 2009: check for functioning cathodic protection if metal components in the sump are in contact with water and remove any debris.

For submersible turbine pumps and under dispenser areas that do not have containment sumps: check for functioning cathodic protection if metal components are in contact with soil or water and remove any debris.

Keep a logbook with dates of inspections, any results, and names of the inspectors.

If you do not know when your sumps were installed, check your facility’s information in our Central Registry. You can also find a licensed UST contractor to determine if your containment sumps are single-walled, contained, uncontained, or used with interstitial monitoring.

Wastewater from Tightness Testing

You need a permit to dispose of wastewater from tightness testing, but your authorization depends on how you plan to dispose of the wastewater. See Disposing of Wastewater Contaminated with Petroleum for more information.

If you discharge hydrostatic testing wastewater within the boundaries of a Municipal Separate Storm Sewer System (MS4), always let the MS4 operator know before discharging, even if you have a permit. City partnership is very important, and it lets them know the discharge was intended.

Recordkeeping

For spill and overfill prevention records, keep logs of 30-day and annual walkthrough inspections, periodic testing and inspection results, installation records for your UST system, and any documentation of repairs or replacements. You can find more information and example logs in the UST Compliance Notebook (RG-543).

More Information

See the following resources for more on PST rules and requirements:

• PST: Compliance Resources
• PST Super Guide (RG-475)
• PST Program

TCEQ's Small Business and Local Government Assistance section offers free, confidential help to small businesses and local governments working to follow state environmental regulations. Call us at 800-447-2827 or visit our webpage at TexasEnviroHelp.org.