Above Ground Storage Tank or AST

Above Ground Storage Tank or AST Common Questions

 

Above Ground Storage Tank or AST, like an Underground Storage Tank (UST), contain heating oil for the purpose of heating homes and buildings. There are specific differences between the two tanks and these are some of the most common questions we are asked regarding ASTs.

What is an above ground storage tank or AST?

Homes, apartments, farms and some businesses that are currently or were heated using diesel heating oil, used an above ground storage tank (AST) to store the heating oil. ASTs are most commonly mounted on a stand or a ground pad either outside or in a basement. ASTs can also be partially buried in the ground, usually in a basement or crawlspace.

Since it isn’t underground, do I really need to be worried about an AST?

Yes, even above ground tanks can leak, resulting in contamination of soil and drinking water supplies. Any oil spill can pose a serious threat to human health and the environment, regardless of where the tank is located.

What is the difference between an AST and a UST?

The distinct difference between the two tanks is this:

  • If the tank and its piping is located 10% BELOW ground surface it is considered a UST, anything ABOVE 10% ground surface is considered an AST.
  • Another exception is that, ASTs are not regulated by the DEQ, therefore not governed the same way as a UST.

For example, if a UST is leaking above 50 PPM (parts per million) the contractor is required to report this to the DEQ and is subject to remediation, based on the level of contamination. After the clean-up has been completed, the UST is then decommissioned and registered with the DEQ. This scenario can also be compared for an out of service underground storage tank, once the tank has been decommissioned it can then be registered with the DEQ.

The circumstances for an AST are different. When an AST is or has leaked, is no longer in-service, or the homeowner is switching to a new heat source, the tank can simply be removed, no decommissioning or registration with the DEQ is required. However, like decommissioning an underground storage tank, each AST removal can bring about a different set of considerations.

What to do with an Above Ground Storage Tank AST when decommissioning is not an option

If you don’t decommission and register the AST with the DEQ, what do you do?

First, we would need to determine where is the tank located?

  • Outside the home
Above Ground Storage Tank or AST

Above Ground Storage Tank or AST – Exterior AST secured to concrete pad foundation.

  • In a basement or crawlspace, with a separate exterior access
Above Ground Storage Tank or AST

Above Ground Storage Tank or AST – AST located in basement with exterior access.

  • In a basement or crawlspace, with access through the home only
Above Ground Storage Tank or AST

Above Ground Storage Tank or AST – AST located within a crawlspace, no exterior access. For this AST to be removed, it will need to be cut into pieces.

Regardless of where the above ground storage tank or AST is located on your property, it is very important to have it removed by a licensed contractor with pollution insurance. If the AST is removed by a general contractor, and they usually DO NOT have pollution insurance, and heating oil is spilled in the house or the yard, the homeowner will be left with the clean-up, not the contractor.

Once the location has been determined:

  • All heating oil and sludge are pumped out, the tank removed and disposed of via recycling.
  • Depending if the tank is on the exterior or interior of the home determines if the tank can be removed as one piece or if it will need to be cut into portions and carried out of the home.
  • If applicable, the fill and vent are removed and holes would be patched.
    • Removing or concreting over the fill eliminates the possibility of an accidental fuel re-fill.
Above Ground Storage Tank or AST

Above Ground Storage Tank or AST – AST Vent (the larger pipe) and fill pipe.

When an Above Ground Storage Tank (AST) Leaks

What would cause an AST leak?

There are numerous reasons an AST can leak; improperly secured tanks, tank corrosion, equipment or support failure, overfilling the tank, or it could be as simple as human error.

Above Ground Storage Tank or AST

Above Ground Storage Tank or AST – Tank that has fallen down, if the contents are not pumped out, diesel fuel would be leaked into the yard.

My AST is leaking, what should I do?

  • Place a bucket underneath the tank to catch the release
    • If the AST is within the home, block all floor drains to prevent discharge into a drywell or sewer
  • Call a qualified heating oil tank provider that can respond to and clean-up a leaking tank
    • The AST would be pumped of all residual liquids
    • Clean-up would be performed to remove any heating oil contamination
Above Ground Storage Tank or AST

Above Ground Storage Tank or AST – Leaking AST, small bowl has been placed underneath the leak to catch the heating oil.

PLIA in Washington State

PLIA Insurance Coverage

In 1995 the Washington Legislature added pollution liability coverage for heating oil tanks to PLIAs responsibilities. PLIA in Washington State assists owners of underground storage tanks to provide available and affordable insurance through a state administered reinsurance program. The program was created in response to the rising number of heating oil tank releases and the significant impact contamination had on property values, as well as the environment. When a clean-up has been completed, PLIA will provide homeowners with a Letter of Finding which states that the site has met the clean-up standards defined in the Model Toxics Control Act.

PLIA can also assist homeowners with the following information:

  • Verifying the validity of required declarations of financial responsibility
  • Provide advice and technical assistance regarding liability and clean-up requirements

What is covered when insured through PLIA?

  • Up to $60,000 to clean-up contamination, not covered by other insurance, on your property and/or a neighboring property
  • The contamination must come from a leak that starts after a heating oil tank is registered with PLIA. The tank may be a UST or an AST
  • The tank must be registered in the current owners name
  • Reimbursement up to $1500 to repair damages on neighboring property (third party coverage) such as landscaping, flooring, painting, etc.

What is NOT covered through PLIA?

  • Leaks from abandoned or previously decommissioned tanks
  • Leaks that start before registering with PLIA
  • Property restoration on your property (first party coverage)
  • Removal/repair/replacement of the tank/lines/furnace
  • Emergency heat restoration
  • Heating oil lost in the release

How do you apply for insurance through PLIA?

  • No cost to register
  • Must complete and submit to PLIA the PLIA registration form
  • You must be registered with PLIA prior to the start of any accidental release in order for the clean-up to be covered
  • When PLIA receives the completed registration form, you will be mailed a confirmation. If confirmation is not received within 14 days, contact PLIA at 1-800-822-3905 or 360-407-0520

How to file a claim through PLIA

  • If a release is suspected or confirmed from your registered heating oil tank, PLIA must be contacted at 1-800-822-3905 or 360-407-0520 within 30 calendar days from the date the tank is disconnected from the furnace.
  • PLIA will investigate the claim, which may include taking photos of your property and the failed tank
  • Owner will hire an approved contractor to do the clean-up
  • All work must be approved by PLIA before the work starts

Who is the Policy through?

  • The Pollution Liability Insurance is covered through The Colony Insurance Company, please click the link to read about the WA Pollution Liability Policy

PLIA Insurance Coverage and Soil Sampling

How to get started, obtaining soil samples through a site assessment

  • The heating oil tank owner must select a service provider to perform the site assessment and is responsible for payment of all costs associated with soil sampling.
  • PLIA will interpret and provide a report to the owner with the results of the soil testing. Each report will provide the following information:
    • No apparent contamination that poses a threat to human health and the environment, no further action is required.
    • Minor contamination is present at the site and further site assessment or clean-up may be required.
    • Serious contamination is present, appears to pose a threat to human health and the environment, immediate corrective action is required.

What are the costs associated with the insurance through PLIA?

  • PLIA in Washington State insurance coverage is required to collect from the tank owner, requesting technical assistance, the costs incurred in providing assistance.
  • Costs incurred may include travel costs and expenses associated with monitoring site assessments, review of reports and analyses and preparation of written opinions and conclusions.
  • The Technical Assistance cost is $350.00 and must be paid in full prior to PLIA issuing its report of review and assessment of data.

Additional PLIA informational websites:

Heating Oil Technical Assistance Program (HOTAP) through PLIA Insurance Coverage

If a tank owner DOES NOT have insurance through PLIA, and it is determined that their tank is leaking, is there anything that PLIA can assist with?

Yes, even if the leaking tank is not covered by the Heating Oil Insurance Program through PLIA, a homeowner can request assistance on tank removal and environmental clean-up under the Heating Oil Technical Assistance Program (HOTAP).

How can HOTAP help my uninsured leaking UST?

Through HOTAP, PLIA can provide advice and technical assistance to owners of active or abandoned heating oil tanks if contamination resulting from a release is suspect. Advice and assistance may include:

  • Review of clean-up plans and reports
  • Interpretation of results from soil sampling through a site assessment or site check
  • An opinion letter from PLIA to the owner regarding the results of the testing

How does HOTAP work?

  • The owner of the UST will perform soil sampling, through a site check or site assessment. The owner of the tank may chose a service provider of their choice to perform any and all site work at the property. The tank owner is responsible for payment of all costs associated with soil sampling, site assessment and remediation.
  • Once sampling has been completed, the results of all testing must be forwarded to PLIA for review and evaluation. A copy of the service provider’s field notes must also be forwarded to PLIA.
  • If testing and remediation has been completed prior to PLIAs review, PLIA will consider providing a review and evaluation of the data. PLIA considers how recently the testing and remediation was completed and will consider the methods of the assessment prior to agreeing to review and evaluate the results.
  • Upon completion of review and evaluation, PLIA will provide an opinion letter informing the owner of the review and assessment of the data. The opinion letter from PLIA will provide the following opinions:
    • Property Further Action Opinion Letter– further remedial action is necessary at the property to clean-up contamination and remediation action is also necessary elsewhere at the site
    • Property No Further Action Opinion Letter – no further remedial action is necessary at the property to clean-up contamination at the site and that further remedial action is still necessary elsewhere at the site
    • Site Further Action Opinion Letter – further remedial action is necessary to clean-up contamination at the site
    • Site No Further Action Opinion Letter – no further remedial action is necessary to clean-up contamination at the site

What is the cost for HOTAP?

The fee for the Heating Oil Technical Assistance Program is $350.00. This fee covers the cost incurred in providing advice and assistance, expenses, review of reports and analysis, and preparation of written opinions and conclusions. The fee must be paid in full prior to PLIA issuing its report of review and assessment of data.

As a homeowner, I’ve discovered my tank has leaked but I’m not registered with PLIA.  I can now register in the HOTAP program to receive a review of the testing results and a letter from PLIA “closing the site”?  This is at a cost of $350?  All other out-of-pocket expenses; sampling, remediation, etc. come out of my pocket?

Yes, to all three questions.

My leaking tank is not registered with PLIA and I opt NOT to join HOTAP, as long as I’ve registered with Ecology I’m fine, correct?

No, the site still needs to be addressed and remediation is required. If a homeowner would like a letter stating the site has been closed through PLIA, they would need to enter into the HOTAP program.

I’m selling my home and the buyer has performed a tank search, and a tank has been found. Can I now register the abandoned tank with PLIA?

No, abandoned tanks CANNOT be registered with PLIA  in Washington State. Only active tanks are eligible for the program.

Risk-Based Clean-Up

Risk-Based Clean-Up

Risk-Based remediation addresses the highest level of contamination from a leaking underground storage tank, with levels reported above 10,000 PPM. According to the DEQ, a risk-based clean-up offers the greatest amount of flexibility and adaptability to site-specific conditions. However, it is also the option that might require collecting additional site data and evaluation of more alternatives than a soil matrix or generic remedy clean-up. Risk-based clean-ups are the most rigorous option, with the collection of several soil samples to determine the magnitude and depth of contaminated soil, as well as how far the contamination has spread. The most important aspect of a risk-based clean-up is the evaluation of current and reasonably likely future risks to human health and the environment.

A risk-based remediation involves a soil investigation, which examines the pathways the contamination has likely spread. This pathway evaluation determines where the contaminants were released, how the contaminants can be transported to new locations and the reasonably likely ways that people may come into contact with them. Tests need to be conducted on enough samples to determine the lateral extent, as well as the depth of the petroleum contamination.

There are three investigative phases of concern while conducting a risk-based clean-up, phase two and three may not be necessary if the area of contaminated soil is limited enough in extent. Below are the steps, in order, that are required by the DEQ in order to close a risk-based clean-up:

Risk-Based Clean-Up and Free Product, Groundwater and Soil Vapor Gas

Petroleum Contaminated Soil (PCS) and/ or Free Product:

Up to seven (7) soil samples are taken to establish a representative sample and delineate the vertical and lateral extent of the pocket of petroleum-impacted soil, and potential or actual groundwater impacts. If it is determined that there is free product or large volumes of heavily contaminated soil, from which product may continue to migrate, mitigating the risk by excavation and off-site removal would be required, to the maximum extent practicable.

Risk-Based Clean-Up

Petroleum Contaminated Soil (PCS) seen during an excavation. The PCS is pictured here in the greyish color.

Risk-Based Clean-Up

The side view of the PCS, here you can see the coloration difference between the contaminated and the native soil.

Risk-Based Clean-Up

Free Product refilling into a sample boring hole

Risk-Based Clean-Up

Free Product within a sampling tube

Groundwater:

Has groundwater at the site at risk or has it been impacted by the diesel contamination?

In order to determine if groundwater has been or could be potentially encountered, a 10’ separation is required by the DEQ between the vertical extent of the contaminated soil and any potential shallow groundwater.

If there is no impact or potential impact to groundwater?

The groundwater investigation is now completed, no further action would be required.

If groundwater has been or has the potential to be impacted, what are the next steps?

A representative well will be installed in the source area to determine if groundwater has been impacted by the release. The installation of the representative well is designed to obtain a groundwater sample to measure, if any, the water level elevation in the contaminated water or soil.

If the samples in the representative well have detections that exceed the DEQs Ingestion and Inhalation from Tap Water Risk-Based Clean-Up levels, a groundwater investigation is necessary. The groundwater investigation determines the extent of the contaminated groundwater, and whether it is limited only to the property of the leaking UST or if extends to neighboring properties.

If the samples in the representative well meet the DEQ Ingestion and Inhalation from Tap Water Risk Based Clean-Up levels, no further action would be required.

The 10’ separation boring cannot be obtained due to site conditions, what happens to the investigation?

If a 10’ separation boring cannot be completed due to examples like refusal (rocky soil, etc.) or if the tank is too deep, per the DEQ a Beneficial Well Survey would need to be conducted.

A Beneficial Well Survey determines if a release of hazardous substances has impacted or has the potential to impact groundwater or surface water, through contaminant migration. These determinations will be used for evaluating exposure pathways in human health and ecological risk assessment; for identifying hot spots of contamination; and for selection or approval of remedial actions at hazardous substance clean-up sites.

The DEQ requires the survey to identify all properties that are in proximity to the site with the leaking underground storage tank, which may be utilizing a water supply well. The well may be used for drinking water, irrigation, etc. DEQ regulations considers that any well on a property that is for domestic use, be accounted for. These surveys can and are conducted within and outside city limits.

Grd Water

Groundwater encountered within an opening within an underground storage tank.

Vapor Intrusion from soil or groundwater:

Vapor intrusion is the migration of Volatile Organic Compounds (VOCs) from the subsurface into buildings. Per the DEQ, vapors released from volatile substances can be slowly released from underground spills. These volatile constituents move upward through the pores in the soil, when the soil is exposed during excavation, as well as, from contaminated groundwater. The DEQ requires Soil Vapor Gas sampling (SVGs) to assess the potential of carcinogenic vapors entering residential buildings. When certain constituents of interest, such as benzene, ethylbenzene and naphthalene concentrations exceed the DEQ Vapor Intrusion into Residential Buildings Standards, soil vapor gas sampling would be required.

To assess the potential cancer risks from vapor intrusion into homes, soil vapor gas sampling is triggered if any of the following variables apply:

  • The plume of contamination exceeds 65 cubic yards
  • There are, or likely to be, buildings within 30 feet of Volatile Organic Compounds (VOCs)
  • A 10’ separation cannot be established between the vertical extent and any potential shallow groundwater

Due to site specific factors, the number and sample locations may vary. Sampling may be conducted within the home or on the exterior of the building, either through the sub-slab and/or the soil.

Risk-Based Clean-Up

Soil Vapor Gas Sampling at the exterior of the property

Risk-Based Clean-Up

Sub-Slab Sampling, in the interior of the building

For a more in-depth overview of the DEQs requirements and standards regarding Risk-Based Clean-Up and leaking tanks, please visit their Leaking Underground Storage Tank Program (LUST site) DEQ LUST Site.

Generic Remedy Clean-Up

Generic Remedy Clean-Up

A Generic Remedy Clean-Up is considered a mid-level contamination, consisting of a release of 501 – 10,000 PPM. This remediation is a soil-only clean-up as long as there is no impact to groundwater, no free product is present and there is no vapor intrusion into the home or building. A generic remedy may require soil removal, as well as additional soil samples around the tank to determine the extent of the contamination. Total Petroleum Hydrocarbon (TPH) concentrations up to, but not exceeding, 10,000 PPM of soil may be left in place if:

  • There is at least three feet of clean soil over the contaminated soil
  • The volume of remaining contaminated soil (over 500 PPM) does not exceed 65 cubic yards
  • Analysis for the presence of benzene, ethylbenzene and naphthalene must be performed on all samples exceeding 2,500 PPM.
Generic Remedy Clean-Up

Generic Remedy Clean-Up – this is the fill cap from a tank that was decommissioned through a generic remedy remediation. The concrete was cut in order to gain access to the tank underneath the concrete patio.

Generic Remedy Clean-Up

Generic Remedy Clean-Up – Fill material from a tank that was being decommission through generic remedy remediation, this tank was found to have leaked at 5710 PPM

Once the investigation of the soils around the tank and the contaminated soil has been removed, the generic remedy clean-up decommissioning of the tank can continue.

In order to establish if a generic remedy is necessary, the DEQ requires a site assessment must be conducted to determine the source, nature, magnitude and extent of the contamination associated with a release from the underground storage tank. The site assessment must specifically address:

Generic Remedy Clean-Up Investigation

  • Determine the presence of free product
    • If there is pooling of liquid fuel in the tank excavation area or if there is clearly visible saturated soil, free product is present and a generic remedy remediation is no longer acceptable.
  • Determine if groundwater is affected and the depth to groundwater
    • During the tank excavation, if groundwater impact is discovered, the DEQ requires the water be pumped from the pit. If the pit remains dry for 24 hours, sampling and clean-up may proceed under the generic remedy. If water returns in less than 24 hours, it is presumed to be groundwater and the use of the generic remedy remediation is not allowed.
  • Determine the vertical and horizontal extent of the heating oil contamination
    • If decommissioning will be performed by removing the tank, two samples must be taken from each end of the excavation, at least 6 inches below the bottom of the excavation. If, by visual observations, additional contamination or odors are detected, samples must be collected from these areas as well.
    • If the decommissioned tank is to stay within the ground, two soil samples are to be taken from each end of the tank, as well as one below the tank bottom. The samples are to be taken no more than six inches from the tank end and at least one foot below the tank bottom. If contamination or odors are encountered, based on visual observations, samples must also be collected from these areas as well.
    • An estimated volume of contaminated soil proposed to remain at the site will be required to ensure that the 65 cubic yard limitation is not exceeded. Results of soil samples analyzed for the presence of heating oil are required to determine both the vertical and horizontal extent of contamination remaining above 500 PPM.

We have provided a link, this provides more insight to understanding more of the DEQs requirements regarding Generic Remedy Clean-Up remediation standards and guidelines.

Soil Matrix Cleanup

Soil Matrix Cleanup

A Soil Matrix Cleanup, which consists of a release of 500 PPM or less, lands within the DEQs simplest level of remediation. Pending that, during the decommissioning process, no holes within the tank are observed, the DEQ will not require any additional sampling or scope of work, in addition to the usual Soil Matrix Evaluation used to close the LUST file.

Standards for a Soil Matrix Cleanup

The standard by which the DEQ closes an open file for a Soil Matrix Cleanup is as follows:

  • Removal or treatment of the contaminated soil is not required
  • An abbreviated risk assessment is allowed for the site, which is called a Soil Matrix Evaluation
  • The tank and the contaminated soil will remain within the ground
  • The final steps include creating the Soil Matrix Report and submitting the report to the DEQ. Once reviewed and approved by the DEQ, the site will be considered DEQ Certified and the site will have a “Closed Status”.
Soil Matrix Cleanup

Soil Matrix Cleanup – Tank found and marked out for sampling. The small circle inside the right side of the marked tank is the fill pipe.

Soil Matrix Cleanup

Soil Matrix Cleanup – While excavating a tank during a soil matrix decommissioning, holes are found within the tank. These holes cause diesel heating oil to leak into the surrounding soils.

Soil Matrix Cleanup

Soil Matrix Cleanup – Excavation of a tank removal soil matrix decommissioning

For more information regarding Soil Matrix Cleanup, please see the DEQ UST Cleanup Manual.

UST Soil Sampling and Tank Inspection

Soil Sampling and Tank Inspection Common Questions

A UST Soil Sampling and Tank Inspection is almost identical to a Soil Sample.  The major difference between the two is that besides sampling between 12″ to 24″ beneath the bottom of the tank, the tank itself is opened up and inspected for its contents.

Why would a Tank Inspection be needed?

There are a couple different reasons that it is required to include the additional service of the Tank Inspection to the Soil Sampling, here are a few examples of why that would be needed:

  • During a tank search an underground storage tank was found, yet the technician was unable to get the fill cap off to determine its contents.  The fill cap may be inaccessible due to the cap being covered over, rusted shut or the fill pipe itself is completely filled and the contents of the tank can not be determined.
UST Soil Sampling and Tank Inspection

UST Soil Sampling and Tank Inspection – Tank found under concrete patio, fill cap inaccessible due to patio pavers.

  • The tank had been decommissioned previously but never registered with the DEQ.  In order for the underground storage tank to be registered with the DEQ, the soil beneath the tank needs to be sampled and the contents of the tank need to be verified.

The Tank Inspection

How do you perform a Tank Inspection?

After the tank has been located and marked out for soil sampling, our technicians will dig down to the top of the tank, cut open the tank and verify the contents.

Once the tank has been opened up, what is the best case scenario?

What we always hope for is clean soil samples and a properly decommissioned tank.  With samples below the DEQ reporting level of 50 PPM and a tank filled with clean material, the UST can then be registered with the DEQ.

UST Soil Sampling and Tank Inspection

UST Soil Sampling and Tank Inspection – Properly decommissioned tank filled with a concrete slurry.

What if the tank has been decommissioned with a proper fill material, but not filled all the way to the top of the tank, and the soil samples come back below the DEQ reporting level?

As long as the samples come in below the DEQ reporting level of 50 PPM, the remaining gap can be filled with additional fill material to ensure the tank has been decommissioned properly.  Once the tank has been certified as decommissioned, it can now be registered with the DEQ.

UST Soil Sampling and Tank Inspection

UST Soil Sampling and Tank Inspection – Tank inspection with gap in the proper fill material, tank will be filled with additional fill material and can then be registered with the DEQ

 

What are additional circumstances that are encountered with Tank Inspections?

Fill Material

  • Gap in proper fill material, below reporting level of 50 PPM:  Fill void with additional fill material and the tank can then be registered with the DEQ.
  • Proper fill material, leaking tank above 50 PPM: Tank has been decommissioned properly, remediation is required to determine that the leak has been contained. Once the clean-up is completed, the tank can then be registered with the DEQ.
  • Improper fill material: Improper fill material needs to be removed and the tank re-decommissioned. Additionally, if the tank is leaking above 50 PPM, remediation will need to take place to clean-up the site. Once the new decommissioning is completed, the tank can then be registered with the DEQ.

Water

  • Water in gap of the proper fill material, below reporting level of 50 PPM: Pump water out of the void and fill gap with additional fill material. Tank can now be registered with the DEQ.
  • Water completely fills the tank: Regardless of the fill material, everything within the tank needs to be pumped out and replaced with new fill material. Additionally, if the tank is leaking above 50 PPM, remediation will need to take place to clean-up the site. Once the new decommissioning is completed, the tank can then be registered with the DEQ.
UST Soil Sampling and Tank Inspection

UST Soil Sampling and Tank Inspection – Liquid found inside of opened tank

  • Tank is opened and it is empty.  If the samples come in below 50 PPM, the tank can be decommissioned and registered with the DEQ.  If the samples come in above 50 PPM, the tank can be decommissioned with remediation and then registered with DEQ
UST Soil Sampling and Tank Inspection

UST Soil Sampling and Tank Inspection – Empty tank discovered during a Tank Inspection.

UST Soil Sampling

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.