Our Underground Storage Tank (UST) program is one of the largest pollution prevention programs at Ecology. Every year, just over 3 billion gallons of fuel are stored underground. We conduct compliance inspections and provide technical assistance to help tank owners prevent leaks and spills.
We regulate more than 9,200 tanks at more than 3,400 facilities, including gas stations, industrial and commercial properties, and government-owned properties. We make sure these tanks and their associated piping systems are installed, managed, and monitored to prevent releases into the environment.
Washington’s UST program is federally-approved. This means that state law, not federal law, applies to UST systems in this state. We are federally required to inspect tanks at least every three years.
Find it fast
The annual fee for each underground storage tank is:
Sources and causes of releases
View our data on the sources and causes of releases from UST systems in Washington.
Other storage tanks
You must report any spills or leaks of petroleum or hazardous substances to Ecology, whether or not we regulate the tank. Report releases affecting water or spills of dangerous materials immediately.
Aboveground storage tanks
Ecology does not regulate most above-ground storage tanks (ASTs). These tanks typically hold petroleum products (like heating oil, propane, or diesel) or other potentially hazardous chemicals. Local fire agencies, counties, and/or cities, regulate and permit ASTs, with two exceptions:
Certain ASTs are subject to federal regulations, including:
Home heating oil tanks
We do not regulate any home heating oil tanks, underground or aboveground. For information about home heating oil tanks, contact the Pollution Liability Insurance Agency (1-800-822-3905).