Underground storage tank program

Our Underground Storage Tank program protects the environment by regulating more than 9,200 tanks across the state. Are you a tank owner? Learn what you need to do to ensure your underground tanks stay safe.

Overview of our program

Our Underground Storage Tanks program is one of the largest pollution prevention programs at Ecology. Every year, just over 3 billion gallons of fuel are stored underground. Our job is to make sure it stays there safely until it goes into your tank.

We currently regulate more than 9,200 tanks at more than 3,400 facilities, including gas stations, industrial and commercial properties, and government-owned properties.

We work to ensure these tanks are installed, managed, and monitored to prevent releases into the environment. The federal requirement is to inspect tanks every three years but we inspect tanks every two and a half years. We conduct compliance inspections at about 1,200 facilities each year and provide technical assistance to tank owners.

Washington has a federally-approved Underground Storage Tank (UST) program. This means that state law, not federal law, applies to UST systems in this state.

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Sources and causes of releases

We collect data on the sources and causes of releases from UST systems in Washington. We are required to report this information under the Underground Storage Tank Compliance Act of 2005.

Home heating oil tanks

We do not regulate home heating oil tanks. For help and information, please contact the Pollution Liability Insurance Agency at 1-800-822-3905 or visit them at www.plia.wa.gov.