Underground Storage Tank

An Underground Storage Tank endorsement is required for owners of storage tanks with all of the following:

Capacity greater than 110 gallons.
At least 10% of volume (including piping) below the surface of the ground.
Contain petroleum or other hazardous substances.

Note: Some tanks may be exempt.

Licensing requirements and additional supporting documents

Business License Application.
Underground Storage Tank Addendum.
Weighing and Measuring Devices Addendum.
Closure and Site Assessment Notice (required for temporary and permanent tank closures and change in service.)
Tank Owner/Operator Training Requirements.
The owner must file an application within 30 days after a new installation is complete, or upon modification or purchase of existing tanks.
A notice of intent to install must also be filed directly with the Department of Ecology at least 30 days before new installation work begins.
All owners of regulated UST's, other than state or federal government agencies, must provide proof of ability to pay costs of a release from their tanks at the liability minimums set in WAC 173-360A 1000 through 1015.

Note: If using insurance, attach the complete insurance policy from the provider, which includes the certificate as set forth in WAC 173-360A-1083. The certificate holder should be:

Business Licensing Service
PO Box 9034
Olympia WA 98507-9034

If you are not using liability insurance, attach a Certificate of Financial Responsibility as set forth in WAC 173-360A-1096.