UST Soil Sampling Common Questions

Whether a tank search has resulted in a UST being discovered or if there is an in-service tank on the property, EcoTech highly recommends soil sampling be completed around the tank.

If you are a buyer, it is imperative for you to obtain soil samples on the underground storage tank, as once you purchase the property, you have now purchased the UST and if it is leaking, are now responsible for the clean-up.

If you are a seller or a homeowner thinking about selling, and you know you have an UST on your property, preemptive soil samples will allow you prepare for pre-inspection complications.

For more information on underground storage tanks and real estate transactions, please see the DEQ Buying or Selling guide for helpful tips DEQs Buying or Selling a Home with a UST

What if a UST is found?

Soil Samples are recommended. Per Oregon DEQ, the best way to determine if a UST has leaked, is to have soil samples collected from under each end of the tank and have the samples analyzed for diesel and heavy oil. Each sample should be analyzed at an independent laboratory that is DEQ certified.

UST Soil Sampling

UST Soil Sampling – Rendition of technician taking soil samples 12-24″ beneath an underground storage tank.

UST Soil Sampling

UST Soil Sampling – Sampling tubes filled with soil from around an underground storage tank. The soil is then placed in a jar and sent to the lab for testing.

There is an in-service tank, should I perform soil samples?

As a prospective buyer, it is essential to test a tank before purchasing the property to determine if it has leaked or is currently leaking. The current property owner is responsible for any necessary contamination clean-up from a leaking underground storage tank. Purchasing a property without testing a tank makes you, as the new property owner, liable for a prior or currently leaking UST.

I’m selling my home and the buyer has found a tank, what are the next steps for me?

EcoTech recommends that you decommission the tank and register it with DEQ. Although, through our experience, buyers and their agents will require at a minimum proof of clean soil samples.

Types of Soil Samples

What are the type of UST soil samples? 

There are three different categories that sample results can be placed into:

Non-Detect (ND)

In-service tank: samples that were analyzed have come back as non-detect and no further tests are necessary. EcoTech does recommend that the decades old tank be decommissioned and a new heat source chosen, as soon as it is practical, before the tank does leak.

Out-of-service tanks: samples that were analyzed have come back as non-detect and no further tests are necessary. EcoTech does recommend that the out-of-service tank be decommissioned within 90 days of the soil samples and registered with DEQ.

*For both the in-service and out-of-service non-detect samples that were taken from each end of the UST, does not rule out the possibility of contamination underneath the soils of the tank, that is why EcoTech recommends decommissioning of the UST.*

50 PPM (parts per million) or less

In-service tank: samples that were analyzed indicate that a leak is present. Although this is a low detection and it is not reportable to DEQ, it indicates a leak has started and should be a concern. EcoTech highly recommends that the tank be taken out-of-service and decommissioned and registered with the DEQ.

Out-of-service tank: samples that were analyzed indicate that a leak is present. Although this is a low detection and it is not reportable to DEQ, it indicates a leak has started and should be a concern. EcoTech recommends that the out-of-service tank be decommissioned and registered with DEQ.

50.1 PPM or Greater

In-service or out-of-service tanks: “The OR DEQ requires that any site where a soil sample analysis shows petroleum concentrations of 50 PPM or greater, must be reported to the DEQ within 72 hours. Remediation will be determined based on the extent of the contamination.” Simply put, the tank is leaking above the reporting limit, EcoTech is required to report the leak to the DEQ, corrective action is now needed to clean-up the site.