Buying a Seattle home with a buried oil tank

5 min read · 5 sections

A buried heating oil tank is not automatically a dealbreaker. An undocumented one often is — not because of the tank itself, but because your lender may decline to fund the loan, and because a leak is a cleanup bill nobody has agreed to pay yet.

Why this stops deals#

Thousands of homes across Seattle and the north-end suburbs were heated with oil before converting to gas or electric. In many of them the tank was never dug out. It is still in the yard, or under the driveway, usually forgotten.

The problem is rarely the steel itself. It is that three separate parties each get a say, and any one of them can end the transaction. Lenders frequently decline to fund a purchase where an underground tank is present and undocumented. Insurers often exclude the resulting contamination from a standard homeowner's policy. And the City of Seattle notes cleanup costs for an oil leak can exceed $10,000, which is a number that has to land on somebody.

None of that is visible on the listing. It surfaces during inspection, at which point you have days rather than weeks to work out who is paying.

Sources

• The hidden risks beneath your yard: retiring your oil heating tank — City of Seattle
• Heating oil tank programs and pollution liability — Washington Pollution Liability Insurance Agency

Three states a tank can be in, and only one is fine#

Almost every argument about oil tanks comes from people using one word for three different situations.

Still in service means the house is heated with oil and the tank is live. That is a known quantity — it works, it has a fill pipe, and it can be converted later. It is not a hidden problem.

Decommissioned means the tank was emptied, cleaned and filled with an inert material, and left in the ground, with a permit and a certificate showing the work was done to standard. This is the common and generally accepted outcome. The paperwork is the whole point.

Abandoned means somebody stopped using it and walked away. No permit, no certificate, no record, no soil testing. This is the one that costs money, and it is far more common than sellers realise, because a previous owner did it and nobody has thought about it since.

How to check before you write the offer#

Most of this is public and free, and it takes under an hour. Do it before the offer rather than during inspection, because your leverage is much better before you are in contract.

1. Look for the physical signsA fill pipe or vent pipe near the foundation, a capped pipe in the driveway, or a patch of settled ground in the yard. Oil-era houses often still have the pipes even when the tank is long dead.
2. Search the decommissioning recordsAsk whether a decommissioning record exists for the address, and get the certificate rather than a verbal assurance. A tank with paperwork and a tank without are different properties at the same price.
3. Read the seller disclosure carefullyWashington's Form 17 asks the seller about known conditions. Read what they said about heating systems and storage tanks, and note what they did not say. Silence is information.
4. Ask for a tank scan, not just a home inspectionA standard home inspection does not locate buried tanks. Locating one is a separate service, and it is inexpensive relative to what it protects you from.
5. If a tank is found, get soil testing before you agree to anythingThe tank is not the cost. Contaminated soil is the cost, and the only way to know is to test. Agreeing to a repair credit before testing means agreeing to a number nobody has calculated.
6. Call your lender before you negotiateAsk directly whether they will fund the purchase as-is, with a decommissioning certificate, or only after removal. Their answer determines what you can even ask for.
7. Ask about state assistance programsWashington has run programs to help with heating oil tank decommissioning and remediation. Eligibility and funding change, so confirm current status directly rather than relying on what a blog said last year.

VERIFY BEFORE PUBLISHING — Programs, permit requirements and lender policies change, and the specifics differ between Seattle and each suburb. This page names the checks, not the current figures. Re-read quarterly and confirm anything numeric with the jurisdiction or the agency before relying on it.

What to do with the answer#

If the tank is decommissioned with a certificate, this is usually a non-event. Confirm your lender agrees and move on.

If a tank is present and undocumented, it is a negotiation, not a walk-away. The seller can decommission before closing, fund it through escrow, or reduce the price. Which one is right depends on your timeline and on what your lender will accept.

If soil testing shows contamination, slow down. That is a different conversation with different professionals in it, and it is not one to resolve inside a five-day inspection window.

Common questions#