Oil tank sweeps are not required by law but are 100% prudent when buying a home built before 2000.  Oil tanks are a Recognized Environmental Condition (REC) and the liability or responsibility of cleaning up a tank leak occurs to the property owner.    An oil tank sweep is the best way to locate buried oil tanks.  Leaking oil tanks (Rust Never Sleeps) and improperly abandoned underground oil tanks are a financial liability and hazard.

Consider that a small oil tank leak can cost $10,000 and some soil remediations can exceed $100,000, oil tanks are a huge liability.

The soil remediation to the left cost $45,000, which included engineering and structural support of the building, restoration of concrete and stairs, and HVAC relocation. 

The oil tank was found buried and hidden under the stairs before purchase.  The buyer dodged a bullet on this one

An oil tank sweep is meant to protect a buyer from purchasing a property with an undisclosed oil tank that can leak and cost tens of thousands of dollars to remediate.   Now the hard part is getting a quality oil tank sweep.

The term oil tank sweep is like saying "I'll have a steak", there is a broad range of types & quality.     While price does not always denote quality, "You get what you pay for" rings true regarding oil tank sweep.

Oil tanks were installed in no standard fashion, size, or location on a property because they were installed by fuel oil dealers, plumbers, builders, and excavation contractors.    Over 30 years of removing oil tanks has allowed Curren Environmental to see this firsthand.   When you do an oil tank sweep you want the company to have years of experience removing oil tanks, and be currently licensed to remove oil tanks, because when you find an oil tank, people want a cost to remove it.

There is no licensing for individuals who perform oil tank sweeps and like hobbyist's treasurer hunters, most people incorrectly rely on a $1,000 metal detector to sweep for an oil tank.     You will find this approach when you get a cost under $300 for an oil tank sweep.   Metal detectors will pick up all metal and cannot differentiate between an oil tank and geology or surface metal like a fence of buried pipes.   

The below snip is from a metal detector scan,  this is the whole report, one page.  I have no idea how the house is heated, oil or gas, or if any evidence of an old buried tank was found inside the house because they do not reference if they went inside the house.

 

 

 

 

The photo to the left is the house where this oil tank sweep was completed.  The photo shows their metal detector on top of where they believe a tank is located, in the rear of the house.

 

This photo shows the view of the front of the house.  In the photo, two pipes are protruding from the side of the house.  These are pipes for a basement oil tank, although the one-page report doesn't state that the home is on oil heat but does state "No vent pipes, fill pipes or fuel distribution lines were found during the inspection."  A qualified company would note the basement oil tank which based on the age of the home increases the probability of a 2nd tank, which could be the metal object they found.  But follow me here the oil tank is in the rear of the house, and the existing tank is in front of the house.  That is weird because the oil tank wants to be near the heater and the more likely location for a buried oil tank would be near the basement oil tank but obviously on the outside of the house.  Turns out there was no buried tank just metallic soil.

The takeaway here is Ground Penetrating Radar (GPR) was not used to scan for an oil tank.  GPR is a commercial application, meaning it is used for commercial and more complex sites.   GPR provides a visual image of what is in the ground, cost is more in the $400, range but you get tens of thousands of dollars of sophisticated equipment that allows you to professionally scan a property.

   

Being licensed to remove oil tanks also helps.  It gives hands-on training to the technicians who scan for oil tanks.  Meaning after you find an undisclosed oil tank you can be involved with the removal of the oil tank so you verify what you found. 

         

 

Does the owner of the property have to be made aware tanks weep is being performed?

A tank sweep is a form of due diligence, like a home inspection, every seller has to allow inspections, although they don’t have to agree to fix anything.  Every seller should be aware that the buyer is paying for these inspections, so they are aware these items are a concern.  Nobody likes to be surprised by problems, which inspections by nature are looking for.

The owner should be aware we are doing an inspection specific to oil tanks because if we find a tank we want it removed and I was told they have no knowledge of any oil heat.

Do you need to go inside the building during a tank sweep?

100% you have to go inside the building and inspect for evidence of prior oil heat.  Anyone not going inside is doing an incomplete inspection. To provide a thorough tank scan, Curren needs access to the basement heater room during the scan and no cars in the driveway.

An oil burner switch and an oil burner fuse inside the door are both clues that are indicative of oil heat.  Curren also sees "cut outs" in the flooring of the basement, or lines sticking out of the flooring, both are clues that an oil tank was present on the property at some point in time. 
 

      

Speaking of visual assessment as part of a tank sweep, one of the photos below suggests an oil tank the other is 100% not an oil tank.  The trained technician knows the difference.

     

 

What happens if you find an oil tank during a tank sweep?

When a tank is found the owner/seller must be informed of the tank and that it needs to be removed and tested to verify no leaks.  But it goes deeper than that, a cascading series of events occurs.

1. The settlement will need to be pushed back typically a month or more as you need time to get permits, remove the tank and get soil sample results. Example: We just had a tank located and removed prior to the settlement they pushed back settlement twenty days on day fourteen we removed the tank and it leaked, now the leak is reportable to the state environmental agency, and you will have to do reporting to the government, which takes time.   As we waited a week for the test results, the settlement was not moved back any further, three days before settlement we get all the test results 100% failure and soil remediation required. The Realtor, mortgage company, and buyer were like deer in the headlights as there was no backup plan.

2. Find a tank, the seller must address the tank for the buyer or cancel the contract and disclose the tank to all FUTURE BUYERS, meaning updating the Disclosure Statement.  A Realtor must update the listing referencing the tank. Example: had one where we found a tank, the seller canceled the contract, and got a new buyer but NEVER DISCLOSED the tank.   Buyer found tank AFTER PURCHASE.   Man, the number of attorneys and people getting sued was large and the buyer walked away winning.

3. Find a tank, and see if the seller will take care of it because as you have just read, they need to do the right thing.  Buyer can push back settlement until at least the tank is removed and soil sample results are returned, and it can be determined if remediation is or is not required. Example: Had this situation occur, but the tank was found under a deck, buyers paid for soil testing where we could test, and contamination was found.   We found cancer, but the extent was not known because the deck prohibited access to drill test borings.   The buyer and seller came to some financial agreement on the purchase and the buyer got monies back or off the purchase price.   We remove the tank and performed a remediation, but the contamination was extensive, and the buyer needs more money to clean up the leak but the seller is saying they agreed on an amount and no more funds will be provided.

 

Tank sweeps, or tank scans are an evaluation of a property for a buried Underground Storage Tank (UST). Unfortunately, these sweeps/scans have become generic to so many and people are unaware of the limitations, between both the companies providing the scan and the technology used.

             

                             Metal Detector                                      Vs.                         Ground Penetrating Radar

Best price, means least expensive technology (metal detector), for example would purchase a 5SE phone vs. the IPhone 12? Maybe for your young kids, but not for you. The best  utilized  technology for locating underground oil tanks is Ground Penetrating Radar (GPR).                     

An example of using a metal detector as opposed to a the Ground Penetrator Radar - Curren was provided a report from a client who asked for an underground oil tank removal. Oil tanks were discussed in the report. The tank locatoror who provided the tank scan with noted the following: “While conducting the oil tank scan it was noticed that there is the possible presence of an oil tank at the front of the home. This was noticed using Schonstedt magnetic locator which detects the magnetic field of ferromagnetic objects. The object that was detected is 3ft x 5ft. After detecting this object a 4 ft probe was inserted into the ground in this area and we detected a object about 3 ft below the surface. A qualified oil tank removal company should further evaluate to determine the size and depth of the possible tank. This company should also conduct proper soil samples to determine if a leak is present at the possible tank.” Several photographs were also included to indicate the meter utilized, and the areas investigated. 

Instead of doing another scan with the Ground Penetrating Radar, the client asked Curren to remove the said underground oil tank found with the metal detector. Curren mobilized equipment and labor to remove the #2 fuel oil UST (subject tank). Curren excavated in the area identified in the Tank Inspection report to a depth of 9’.

No tank was located. Curren then excavated toward the residence additionally to 9’. No tank was located. Curren inspected the basement for copper lines and no copper lines were found.

Conclusions & Recommendations

The conclusions are based upon the review of available information, field observations and test results obtained during this project. Curren Environmental, Inc. does not assume any responsibility for using this report for purposes other than those indicated in the specific area investigated.

Based on onsite observations, the areas indicated in the report were investigated, no underground storage tank was located in this area. The client, ended up spending a large sum of money to remove an oil tank that was not there.  

What is a metal detector? "Metal detectors use electromagnetic fields to passively or actively detect the presence of metallic objects. Passive detection measures the changes in the Earth's magnetic field caused by an object."  The photo below shows some debris, that debris was located by a metal detector.  Curren was contracted by client to remove the "underground oil tank".  The metal detector tank sweep found debris, not an oil tank. 

What is a ground penetrating radar system? Learn more here.

 

 

What  happens when a home inspection finds a possible underground oil tank?

A common request our office receives regarding a tank sweeps.

"Hello, I'm selling my home and we suspect that the buyer did a tank sweep with a metal detector vs GPR. They supposedly think they found a tank on the property. We do not see any evidence of a tank, nor was one disclosed by the previous owner (who bought the home in the 70s, house is 80 years old). Is it possible that this 'tank' is just a gutter drain pipe, part of our sprinkler system and/or rubble backfill such as a chunk of concrete sidewalk with rebar or metal containing soil? If so, would a GPR scan be conclusive? Thanks."

This is a common situation we get from property owners who are told they have a buried oil tank.   The owner has the question regarding if the meta detector is reliable.    Here are some common talking points...

1. The property owner is unclear how the suspect tank was found.  Was it found with a Metal detector, or  Ground Penetrating Radar or both? (both GPR and a metal detector would be best) The solution would be having the owner receive a copy of the Tank Sweep Report so they would have a baseline regarding what they found and where. Yes, every professional service should come with a report, no report, then question how professional the service was.
2. The property is over 70 years old, so while the owner has no knowledge that there was an oil tank, they also have no documentation that there was not an oil tank. A 70 year old property most likely had oil heat at one point in time as oil was very popular in the past and other fuel sources such as natural gas was not commonly available or financially appealing until the 1970's.
3. The tank scan found a buried object, presumably metal. If only a metal detector was utilized, you can't say 100% if the metal found is a tank as metal detectors detect metal and properties have all sort of buried metal. Metal can be in the soil naturally, you could have buried debris, buried metal pipes or surface metal (like a fence) that distracted the metal detector and have a false buried metallic signature reading. Happens all the time. A metal detector on a sandy beach is great it will find buried metal, likely a bottle cap, but people hope for coins or expensive jewelry. People paying a couple hundred dollars for someone to use an $800 metal detector to find a tank are also helpful.

The photo below was where a metal detector thought there was a tank.  There was no tank, just soils with a metallic signature.

The guy in shorts, is using a $900.00 metal detector and found a suspect tank in the front yard.

When you scan for a tank, the more expensive the equipment the better.   GPR (Ground Penetrating Radar) costs tens of thousands of dollars because it has the technology to do the job.

 Effective Oil Tank Scan or Oil Tank Sweeps like on commercial sites would use GPR as it will                            provide a signal (image) of buried objects.

The signal above shows the underground oil tank. 

Purchasers of commercial properties are more aware of the liability associated with leaking USTs (Hundreds of thousands of dollars) compared to a residential home buyers (Homeowners think a few thousand dollars is a lot.) So on the commercial side of real estate tank sweeps are completed with GPR, not metal detectors. Most environmental consultants that perform tanks weeps will use GPR and discount the cost for residential sites. Nobody wants to see someone buy a house and find a $50,0000 cleanup is required.

What if a buyer finds a suspect tank?

This is a really hard question because it relies so much on the quality of the tank sweep.    If they used GPR, if the property is likely to have had an oil tank (older the home, the more likely) and if the buried anomaly has the signature of a tank.  Well then you have to excavate and confirm that object is an oil tank.

Who pays for the oil tank removal?

Owner will pay 98% of the time as finding a hidden oil tank is a defect that needs to be addressed.

Do they have buried oil tanks at the beach (shore)?

If the home wanted heat, then yes homes along the coast and on islands had buried oil tanks.  Oil was king up until the late 1970's in New Jersey.  The photo below is of a home we scanned on a barrier island.  Many older beach houses eventually converted to natural gas, as gas could also  fuel the stove, dryer,  hot water heater etc.   After conversion to gas, it was not uncommon that the tank was just left in the ground.  So short answer beach houses had oil tanks.

What if a suspect tank is found and we don't believe its a tank?

Short answer prove your opinion right and dig it up and verify its not a tank.

What is the best tank sweep?

Using Ground Penetrating Radar is the best technology for finding buried tanks at properties, period.  Can you use a metal detector to verify a GPR signal that identified a tank?  Sure, always verify the object is metal.  GPR can't penetrate metal so when a GPR sweep pings a tank, it means the radar can't penetrate the object (likely a metal tank) but there are buried concrete tanks.  Metal detectors can verify an object is metal, but a metal detector  should not be used to be your sole technology

Understand the process of a tank sweeps and what happens after a tank sweep.

The best situation regarding a tank sweep is finding a tank, therefore it can be removed and soil tested to prove that no soil remediation (cleanup) is required.

A hidden or an underground oil tank is a major financial liability when buying a home, because rust never sleeps and oil leaks from the tank. Soil remediation from leaking oil tanks can easily cost into the tens of thousands of dollars.   A tank sweep of any property is always recommended unless you can document the site never had oil heat, unfortunately older homes had oil heat since it was the only option after coal use.

Should I buy a house with an underground oil tank?

An underground oil tank can make a home harder to sell or worth less to a potential buyer, how does a $32,000.00 oil tank cleanup ding the value of a home?  How about a cleanup over a $100,000?  They happen as well.    A known oil tank can also increase the chances of complications with getting to the closing table and the home sold. Mortgage lenders are wary of buried oil tanks and may refuse to lend on a home with an underground tank.  Appraisers and insurance companies may also flag the tank as a liability and want it addressed.

What is the life expectancy of an underground oil tank?

The average life of a UST is about 20 years (if you bought a middle of the road tank today, that is your warranty.) However, with the tank buried, other factors will influence the lifespan of underground tanks, including the gauge of its steel, geology, corrosivity of the soils, etc. 

FACT:  most tanks were used past their design life expectancy and left in the ground unused past their life expectancy as well.

How do you manage the liability with an oil tank?

The liability of an oil tank pertains to leaks that occur and the state mandated cleanup of the oil leaks.   The best situation regarding a tank sweep is finding a tank so it can be removed and tested to prove that no cleanup is required.

What happens if the tank sweep does not find a tank but points to a tank being removed?

This is not your best scenario because now you do not know if the tank leaked or where the tank was located. Clearly not finding a tank means your investigative work is not complete, because you do not know if the tank leaked.   Tank sweeps cannot find removed tanks, so you are tasked with historical research on who removed the tank.    So you will be tasked with doing soil borings with laboratory testing to ensure there is not residual oil contamination from the removed tank. 

The best approach is to assume the tank leaked until proven otherwise.

Bottom line you have to make an effort to find where the tank was located.   Sometimes owners get a conscience  and will admit that a tank was removed, they just did not think that knowledge was relevant at that time. Sometimes a tank sweep can point to a likely area of where the tank was located.

We had a case where an owner removed their own tank in the backyard without a permit.   They eventually were going to sell the home and did not want the tank as an issue. The final cleanup was around $40,000. Someone admitting to a bad thing is not common, but we do see it happen.

 

Sometimes we can find the tank grave, other times we have to do a grid of soil borings in the suspected area to try and find the tank grave and to test soil.

Tank sweeps that point to a removed tank will lead to soil testing in the area of the removed tank, unless of course a report exists of the tank removal with testing and a clear statement that the tank did not leak. Best case you find no contamination, worst you find contamination, which is reportable to the state and further work would be necessary.

 

The following two photos show where a tank was removed 20 years ago, so we had to do soil borings to evalaute for oil.  One of the two sites had oil contamination, do you know which one?

 

Be aware there have been many tanks that were removed, that leaked and were not cleaned up. Owner hoped no one will look or test the area.  If you don't have  a report that includes laboratory data saying the tank did not leak, you don't have what you need to remove the liability of the tank.

 

What about if a tank sweep finds a tank?

Well if the tank was not previously disclosed it is news to both buyers and sellers.  And since no one knew about the tank, the tank needs to be removed and tested.

 

What about if a tank sweep finds a tank, can I test the tank?

Realistically, since you will not be using the tank, (ever) the smart move is to remove the tank and test soils where the tank was removed from.    Soil borings can cost almost as much as tank removal and you cannot test under the tank so you will not be $100%.  You can have contamination under the footprint of the tank which can require remediation.   To be fair if you have contamination under the tank depending on where the tank is located, you won't have a $40,000 cleanup, but you could spend $5000 to $10,000.  

 

What about if a tank sweep finds a tank, can you pivot and then tell me if the tank is leaking?

Tank sweeps use mobile radar units (see below photo on the left).  These units are carried in a SUV.  To perform soil borings you need a drilling unit which is carried on a trailer and towed by a pickup trucks (see photo on the right).    Both pieces of equipment are over $50K and are not brought to a tank sweep typically as you do not know if you will need to drill and if you read the above question you can see why removal is better.  In addition every state requires that you obtain a underground utility markout before you drill or dig, this can take 3 to 4 days and is not obtained for a typical tank sweep.    You also typically do not have permission from the property to drill on their property, tank sweeps are non invasive. 

 

Need to learn more about tank sweeps? Click here.