Frequently Asked Questions2025-12-17T18:10:02+00:00

Frequently Asked Questions

Frequently Asked Questions

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How do I know if my underground heating oil tank is leaking?2026-01-19T22:11:33+00:00

Underground Heating Oil  Tank Leaking

The majority of residential underground heating oil tanks have an age range of 50 to 70 years, during which time the likelihood of leaks may increase.

Click below to explore several straightforward methods for assessing whether your underground heating oil tank is experiencing leaks!

What if my tank leaks?2026-01-19T22:26:29+00:00

What if my tank leaks?

If your tank leaks, you should call us at Tanks By Dallas immediately so we can assist you.

What is an “abandoned” underground oil tank?2026-01-19T22:30:18+00:00

What is an abandoned underground oil tank?

Many underground oil tanks are no longer being used, or are rendered obsolete by electric heaters or natural gas. An underground oil tank that is no longer being used is considered “abandoned.”

What if I am no longer using my underground home heating oil tank?2026-01-19T22:29:49+00:00

What if I am no longer using my underground home heating oil tank?

If you have switched from home heating oil to natural gas or electricity as a means of heating your home, and your heating oil tank is no longer in use, and known as abandoned. Abandoned underground storage tanks that are out of service for 12 months must be properly decommissioned. If removal isn’t possible you can decommission your home heating oil tank by closing it in place. Closing in place involves pumping out the oil, triple rinsing the tank, then filling the tank with an inert solid material.

Have all unused heating oil removed from your tank

Tanks by Dallas and The Washington State Department of Ecology recommend that you have all unused heating oil removed from your tank. 

How long should I expect an underground oil tank lifespan to last?2026-01-19T22:29:20+00:00

How long is an underground oil tank lifespan?

A common life expectancy of underground oil tanks is approximately 10-15 years, it is also possible for them to last longer. The older a tank gets the likelihood of a leak happening increase. The best way to avoid potential problems associated with a leaking tank is to have your tank taken out of the ground and have a new tank installed, either underground or aboveground.

What should I do with my abandoned underground oil tank?2026-01-19T22:26:56+00:00

What should I do with my abandoned underground oil tank?

The recommendation of  the Washington State Department of Ecology is permanent closure for abandoned underground storage tanks this is also required by many local Fire Departments. Decommissioning a tank is the process of permanently closing a tank. Removal of heating oil and sludge from the tank is also involved in decommissioning abandoned underground oil tanks.

Abandoned underground oil tanks often have been known to contain oil still in them. To help prevent possible soil and groundwater contamination, you should arrange to have the oil removed from your abandoned tank if you do not immediately decommission the tank.

Why should I decommission my abandoned underground oil tank?2026-01-19T22:25:57+00:00

Why should I decommission my abandoned underground oil tank?

Abandoned underground oil tanks are a potential source of soil and groundwater contamination. Underground oil tanks should be decommissioned whenever they are no longer used, if they have questionable structural integrity, or if they are leaking.

According to the Model Toxics Control Act, a tank owner may be held liable for contamination caused by a leak.

Often the abandoned tank does not become an issue until the homeowner decides to sell their home. The inspections done before closing exposes the abandoned tank, resulting in the lending institutions and homebuyers requiring sellers to remove or decommission the abandoned heating oil tank.

How do I know if the previous owners had the tank decommissioned?2026-01-19T22:24:51+00:00

How do I know if the previous owners had the tank decommissioned?

Give us a call at Tanks By Dallas 206-365-0291 or fill out this form and we will check for you.

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