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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