UST Tank Search for Sellers

UST Tank Search for Sellers – Common Questions

As a homeowner, you may be thinking about or are preparing to put your home up for sale. For some homeowners, you may want to perform a tank search to prepare yourself for any unforeseen surprises during the home inspection period. On the other hand, you may know that there is a tank on your property that was decommissioned and never registered with the DEQ or that there is an abandoned oil tank, but you don’t know where. These are some of the most common questions that we are asked regarding the tank inspection process and important information you should know before you sell.

What is an underground storage tank (UST)?

Homes, apartments, farms and some businesses that are currently or were previously heated using diesel heating oil, used an underground storage tank (UST) to store the heating oil. The USTs were usually buried in the yard, and copper tubing or steel piping was installed to deliver the diesel from the tank to the furnace. In Oregon, an estimated 100,000 USTs were installed for home heating.

UST Tank Search for Sellers

UST Tank Search for Sellers – Rendition of an underground storage tank (UST) buried in a yard, with the supply lines running into the home.

Why should I worry about an UST?

Underground storage tanks are made of steel, which are selected for their strength, not for their corrosion resistance. Therefore steel USTs rust through, given enough time. Like a roof, steel storage tanks have a life of about 25 years, and like a roof it is cheaper to replace the tank or convert to another heat source before it leaks and the damage is done.

UST Tank Search for Sellers

UST Tank Search for Sellers – Shot from interior of tank, many small holes in the UST, which will cause diesel fuel to leak into the surrounding soil.

Performing the UST tank search

How do you find an abandoned UST?

The best way to determine if there is an abandoned oil tank on the property, is to conduct a tank search. As the homeowner, you may also look for these tell-tale signs of an abandoned oil tank:

  • An Oil Fill Pipe, these are usually close to the ground and near where the furnace is located in your home.  The lid itself will usually indicate OIL in the center of the cap.
UST Tank Search for Sellers

UST Tank Search for Sellers – Fill pipes can appear in multiple places within a property, in a walkway, grass, driveway, and even under a deck are a few examples.

  • A Vent Pipe, this is usually attached to the home, about two to eight feet up the side of the house and it is 1.25 to 1.5 inches in diameter with a small vent cap on it.


UST Tank Search for Sellers

UST Tank Search for Sellers – 4 different types of vents and their locations.  Fill vents can come in different sizes, colors, and may be placed at varying sections of the home.

  • Product lines, may be found sticking out of the ground in the yard, in a crawlspace or basement floor.  Product lines may still be attached to a basement or crawlspace wall next to water or gas pipes.
UST Tank Search for Sellers

UST Tank Search for Sellers – Crimped product lines may appear as random pipes sticking out of a basement floor or out of the dirt near the home in the yard. A product line may also appear running up a wall in a basement or crawlspace, like the far right picture (the thin line on the right)

  • Patching, will be present on a basement floor, it appears as though a pipe has been removed and covered with concrete.  The patching may appear as a bad “patch job” with numerous bumps and grooves.
UST Tank Search for Sellers

UST Tank Search for Sellers – Patching on a basement floor.

How do you perform a tank search?

EcoTech first will perform a Tank Background Search, this entails a detailed examination of state and local databases, as applicable. Besides years of on-the-job experience, our technician conducts a visual inspection for product lines and fill or vent pipes, utilizes metal detectors and Terra, our specially trained Petroleum Detection K-9.

UST Tank Search for Sellers

UST Tank Search for Sellers – Terra finds a tank within a planter.

UST Tank Search for Sellers

UST Tank Search for Sellers – The tank that Terra found is marked out. The purple arrow indicates where the vent pipe has been removed from the siding. The red arrows indicate the length of the tank, marked with orange flags as well as the tip of the measuring tape.


Underground Storage Tank or UST Decommissioning

Underground Storage Tank or UST Decommissioning Common Questions


What does it mean to decommission a UST?

The most generic term, is to take the tank out of service.  Underground Storage Tank or UST decommissioning is accomplished by ensuring the tank has been properly cleaned and removed or completely filled with an inert material. The inert material consists either of perlite, a sand-like material or slurry, concrete.

If the tank is to be registered with DEQ, two soil samples will be taken from inside the bottom of the tank, after being pumped and cleaned, and analyzed for diesel and heavy oil. Each sample needs to be analyzed at an independent laboratory that is DEQ certified.

If the samples come back as non-detected, the tank can be then registered with the DEQ.

If the samples come back above the DEQ reporting limit (50.1 PPM), remediation will need to take place and once the corrective action has been completed, the tank will be registered with DEQ.  If soil remediation is need, please see our Decommissioning via Heating Oil Contaminated Soil Clean-Up page.

Why should homeowners decommission their UST and register it with the DEQ

I’ve emptied my tank of oil years ago and don’t use it any more, doesn’t that mean it is decommissioned?

No, in order to decommission the tank you will need to take the tank permanently out of service. This is completed by either removing the tank or filling it in place with an inert material.

Can I decommission my own UST?

According to the DEQ, it is legal for a homeowner to decommission their own UST, assuming that you perform the work yourself and comply with all applicable local, state and federal rules. Before deciding to decommission your own tank, the DEQ highly recommends that you read the DEQ Cleanup Guidance for Homeowners to understand the full scope of work involved in completing a decommissioning project. DEQ Decommissioning Guide for Homeowners

I’m selling my home and have switched over to gas years ago, should I decommission my tank?

It is not a requirement to decommission your tank before selling your home. Unfortunately in this highly active real estate market, many buyers will require at a minimum, proof of recent clean soil samples. Additionally, you will need to provide the buyer with documentation that the tank has been pumped of all of its contents. The documentation that the DEQ requires is dated receipts from the company that pumped the oil out of the tank; or receipts from the oil recycling company, if you pumped the tank yourself.

Do I have to decommission my UST?

No, it is not a requirement to decommission your tank once you stop using it.  However, if you are thinking about selling your home, most buyers and their agents request decommissioning and registration before closing. Per DEQ, you will need to ensure that the tank has been emptied of oil and you will need to provide that documentation to the new buyer.  DEQ Requirements for Tanks No Longer in Use

Do I have to register my UST?

It is not required by DEQ to register the tank, but it is highly recommended. However, if you are decommissioning the tank as part of the sale of the home, this is usually a prerequisite prior to closing.

Why should I register my UST?

There are three primary benefits of registering the UST decommissioning with the DEQ:

  1. The decommissioning becomes public record.  So, even if your copy of the paperwork is misplaced or the name of the contractor that performed the work is forgotten, the record remains in the DEQ files.
  2. When the DEQ changes any of their rules (i.e. reporting limits, remediation guidelines, etc.), previously closed or registered tanks are “grandfathered” in.  Tanks that were decommissioned and not registered are subject to the new rules.  For example, over time the DEQ required the locations of soil sampling to change.  Meaning a previously unregistered decommissioned tank, would need to obtain additional soil samples to bring the tank up to the new DEQ sampling requirements.
  3. Most buyers are requiring DEQ registration because they don’t want to deal with future DEQ rule changes.  Even if you don’t plan to sell the property any time soon, registering the tank now can prevent added costs prior to and during a future sale.

I have a tank that was decommissioned years ago, but never registered with the DEQ, how do I now get it registered?

In order to establish if the tank has been decommissioned properly, soil samples and a tank inspection would be required. Soil samples need to be taken in order to determine if the tank had leaked prior to decommissioning. A tank inspection is necessary to establish if the tank has been decommissioned properly.

If the soil samples are clean and the tank has been decommissioned properly, the tank then can be registered with the DEQ.

USTs that have been Decommissioned inproperly

What happens if it isn’t decommissioned properly?

There could be a couple of different reasons a tank has not been decommissioned properly.  There may be inadequate or contaminated fill material, water within the tank or simply something that shouldn’t be in the tank (i.e. paint cans, large rocks, etc.).  Besides what is inside the tank, the soil samples will need to be taken into consideration to allow the tank to be certified as decommissioned to register with the DEQ.

  • Fill Material:  If the fill material within the tank is not an approved by the DEQ, that material will need to be removed and the tank will be re-decommissioned to DEQ standards for certification.  The same reasoning will go with contaminated fill material, even if it is DEQ approved material.  The contaminated material will need to be removed and the tank will need to be re-decommissioned to DEQ standards for certification.
  • Water:  If there is water within the tank, all water will be pumped out of the tank and re-decommissioned in order to certify with the DEQ.
  • Unconventional Items:  From time to time, items are found within a tank that should NOT be there.  Items such as large boulders, paint cans, trash cans and even tires have been discovered within a tank.  If this situation does arise, all items will need to be removed and disposed of in a landfill and the tank will need to be decommissioned.
Underground Storage Tank or UST Decommissioning

Underground Storage Tank or UST Decommissioning – Concrete, pain cans and water found within a tank.

What exactly do you do to decommission a tank?

In order to decommission an underground storage tank, we need to follow some step-by-step processes to ensure that we are able to take soil samples and inspect the tank properly.  This is the process by which EcoTech begins each in-place underground storage tank decommissioning project:

1.  We dig down, expose the tank and cut it open.

Underground Storage Tank or UST Decommissioning

Underground Storage Tank or UST Decommissioning – Exposed tank top.

2.  All tank contents are removed; heating oil, residual liquids, sludge.

3.  Clean and dry the tank interior and inspect it for holes.

Underground Storage Tank or UST Decommissioning

Underground Storage Tank or UST Decommissioning – Holes from within a tank.

4.  Collect soil samples from the inside and through the bottom of the tank.

Underground Storage Tank or UST Decommissioning

Underground Storage Tank or UST Decommissioning – The technicians cut two holes in the bottom of the tank to expose the soil underneath, two samples are then “grabbed” underneath the tank bottom.

5.  Soil Samples are submitted to the lab the same day for analysis, with results typically back the next business day by noon.

6.  Pending favorable laboratory results (less than 50 PPM), the tank can be backfilled with perlite or slurry.

***If soil sample results come in above the 50 PPM, remediation would be required to bring the site up to DEQ requirements.  (Please see our Heating Oil Contaminated Soil Clean-Up section for additional information on remediation Clean-Up with Decommissioning).

Underground Storage Tank or UST Decommissioning

Underground Storage Tank or UST Decommissioning – Tank filled with slurry.

7.  After the tank has been filled, the tank is then covered back over with the previous landscape (i.e. grass, concrete, dirt, etc.).