Washington Department of Ecology

State of Washington Department of Ecology

The Washington Department of Ecology does not regulate the use or operation of residential heating oil tanks, like the State of Oregon does. However, some local governments may have different requirements or guidelines that may apply to residential storage tanks. Regulations and policies vary from place to place and may change from time to time.

Are there specific concerns I should have as a homeowner if I have an abandoned oil tank on my property?

  • Tanks can develop holes and release heating oil into the soil. The released oil can contaminate groundwater, surface water, storm sewers, and cause vapor problems in nearby buildings. Under the state Model Toxics Control Act, the tank owner may be held liable for damage caused by a leaking tank.
  • Corrosion can cause underground tanks to deteriorate, making cave-ins a possibility. The homeowner could be held liable for injuries caused by a cave-in.
  • Before finalizing the sale of a house, lending institutions and home buyers may want sellers to remove or “close” unused heating oil tanks. To “close” a heating oil tank, the homeowner has the tank cleaned out and filled. The tank is then left buried in the ground.
Washington Department of Ecology

Washington Department of Ecology – tank found within a backyard in Vancouver, vent pipe can be found running along the side of the house to the left of the window. The sampling of this tank resulted in a Risk Based Clean-Up.

How does Ecology prefer decommissioning take place?

Ecology recommends that the tank is removed with proper soil samples taken, and remediation, if necessary. However, decommissioning the tank in-place is also acceptable, as long as soil samples take place and remediation is completed, if necessary.

Can I decommission my tank as a homeowner?

There is no law prohibiting homeowners from doing their own decommissioning. Although, Ecology does not recommend doing the tank work yourself because of the potential safety risks. Hiring an experienced contractor is advised, as working on an underground storage tank can be dangerous. Under certain conditions, tanks can explode. Working in the excavation pit, cutting open or handling heavy tanks, and using power equipment also pose risks to the homeowner. Ecology recommends that homeowners hire an experienced contractor to perform decommissioning work.

Leaking tanks and the State of Washington Department of Ecology

What if a tank has leaked?

Knowingly using a leaking tank is negligence. If you discover that your tank is leaking you must take immediate action to stop the leak. In most cases where a tank has leaked, only the soil near the tank is affected. Sometimes, however, the heating oil may also have contaminated groundwater or surface water. It is the homeowners or contractors responsibility to:

  • Evaluate the extent of contamination caused by the leak
  • Evaluate the extent of the contamination caused by the leak
  • Determine if it is a threat to human health and the environment
  • Clean-up any contamination caused by the leak

Should I report the leak to Ecology?

Minor Leaks or Spills that affect only the soil near the residential heating oil tank do not have to reported to the Department of Ecology.   However, if the minor leak was discovered during the process of the tank being decommissioned, Ecology does recommend reporting the minor spill through the ERTS program.

Contaminated Soil above 2000 PPM does need to be reported to the Department of Ecology. Any groundwater, surface water, free product or vapor intrusion should also be noted during the reporting process.

How do I report a leak to Ecology?

All confirmed releases must be reported to the Washington Department of Ecology within 24 hours to the ERTS SYSTEM. A leak can be reported via a phone call or through the online reporting system.

Should I clean-up contamination?

Absolutely, and the Department of Ecology recommends that homeowners hire a qualified clean-up contractor to perform the remediation. When the clean-up has been completed, the contractor should give the homeowner a copy of the clean-up report. Clean-up reports of minor leaks do not need to be sent to Ecology, as they do not track or report on these clean-ups. Clean-up reports on more extensive leaks do need to be sent to the Ecology regional office, as they do keep track of and report on these sites. All reports should be kept by the homeowner for their records and the remaining life of the property.

Does the Department of Ecology have a LUST list like the State of Oregon?

Yes, it is called the Confirmed and Suspected Contaminated Site List (CSCSL). However, the majority of the sites on this list are large properties, with larger leaks (i.e. gas stations). It is extremely rare when a residential property does appear on this list, reasons that a site would appear on CSCSL is as follows:

  • When a property has been reported, but after 90 days, no closure and/or continued work to complete the remediation has taken place.
  • If groundwater has been encountered, the property automatically gets put on the CSCSL. The homeowner/contractor then has to go through the voluntary clean-up to get taken off the list. Ecology then works with the homeowner/contractor to get off the list by providing opinions on the work being completed and to verify if meets the status of no further action.

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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.