Soil Sampling in Washington

Soil Sampling in Washington State

Like Oregon, in order to determine if a tank is currently or has previously leaked, an investigative process needs to take place through soil sampling. Again, showcasing the differences between the two states, soil sampling in Washington State separates this function into either a Site Check or a Site Assessment.

Additionally, when the initial soil sampling takes place, to determine if contamination is present, the State of Washington requires a minimum of three (3) samples be taken. One sample must be taken from each end of the tank and the third sample must be taken from the middle of one side of the tank. This is unlike OR, in that, the DEQ requires only two (2) samples be taken from each end of the tank. The three (3) soil sampling requirements are the same as when decommissioning an underground storage tank in place or by removal, as long as no obvious contamination is discovered.

Soil Sampling in Washington

Soil Sampling in Washington – three (3) soil samples are taken in a Washington UST. A sample must be taken from each end of the tank and one from either side of the tank in the middle.

Site Check is the investigation of an underground storage tank site for the presence of a release when evidence indicates that a release may have occurred, but existence of such a release has not been confirmed. Once the existence of a release has been confirmed, the release shall be reported to the State of Washington Department of Ecology.

Examples for a site check include:

  • Environmental contamination may be suspected and can include, but not limited to, constituents in soils, basement, groundwater and/or surface waters.
  • If environmental contamination is discovered off site and a UST is a suspected source of the release, the department may require a site check to confirm whether the UST system is the source of the release.

Site Assessment is an investigation to determine if a release has occurred: it may be required as part of a routine closure, change-in-service, and temporary closure extension, or as directed by the Department of Ecology.

  • For the purpose of a real estate transaction or to determine the state of an in-use or abandoned underground storage tank, a site assessment is conducted.
  • If an UST System is being decommissioned in-place or removed, a site assessment must be conducted after the UST system is emptied and cleaned and all liquid and accumulated sludge has been removed. While removed, a site assessment must be conducted following tank removal.
  • If a UST system was permanently closed or abandoned before December 22, 1988 and the department determines that suspected releases from the UST system may pose a current or potential threat to human health or the environment, the department may require a site assessment to be conducted. If an abandoned tank contains product, a site assessment is required.
  • Owner/operator applies to the department to extend a temporary closure of an UST system beyond 12 months, a site assessment must be completed before the application extension will be considered.

Leaking Soil Samples in Washington State

Contamination has been verified through soil sampling, within 24 hours the leak must be reported to the Department of Ecology. Department of Ecology reporting can either be completed through contacting the state directly or through their online system.  Once the contamination submission has been received by the State, an ERTS number will be given to the person who reported the leak. The ERTS number will also be forwarded to PLIA, as PLIA has an agreement with Ecology to evaluate the adequacy of any independent clean-up action performed by the requirements in the Model Toxics Control Act.

PLIA, can also provide homeowners the option of insuring their underground storage tanks before they leak, as well as helping after a leak has been discovered. Please see detailed information on our PLIA informational page.