Underground Heating Oil Tank Testing
Curren provides oil tank testing for underground storage tanks, heating oil tanks, and aboveground storage tanks. If you are selling or buying a property with an active in-use oil tank you want to have the oil tank tested for leaks, since any leak or contamination is the responsibility of the property owner. Our expert services can cover oil tank location, oil tank testing via soil testing, and exploratory digs.
How do you test an oil tank?
For an aboveground storage tank, (AST), you complete a visual assessment of the oil tank system, you may also do soil testing if the oil tank is outside on dirt. On either end of the oil tank, a 6” deep hole would be advanced with a stainless-steel auger, and the recovered soils screened with a photoionization detector (PID). Samples then are submitted to a state-licensed laboratory for analysis. Labs typically take about seven business days to complete testing, years ago it used to be ten to fourteen days, so time frames have gotten better. Collected from the 0-0.5’ depth interval and analyzed for Extractable Petroleum Hydrocarbon (EPH) analysis, which are the NJDEP soil screening parameters for #2 fuel oil in soils. AST tank testing or AST inspections also evaluate the type of tank, and condition of tank to evaluate or predict life expectancy. The photo bottom right, well this evaluation would be important for this tank so the owner, who is the typical buyer, knows if the tank just visually looks bad or if it is near or past an expected life expectancy and needs to be replaced.
How do you test a buried oil tank or UST?
Advance soil borings around the perimeter of the tank location on three sides. The photo on the left is the actual drilling unit needed to advance the soil testing boreholes. The borings will consist of a 2” diameter core advanced below-grade surface. The photo on the right shows the actual soil cores that are extracted from the ground and tested for oil. Surface disruption is nominal.
The borings will be attempted to be advanced to a depth of approximately 2' deeper than the tank bottom in the event the very bottom of the tank leaks you want to catch that oil You also Field Screen each soil boring throughout the length of the boring with a Photoionization detector (PID/vapor meter) capable of detecting petroleum. You spot-check on-site for oil in the soil. Although on-site testing and physical evaluation are important, you want independent laboratory testing of the soil.
Why no testing between the tank and the dwelling?
Look at the oil tank layout - you will note deeper buried oil lines that extract oil from the tank and feed the heater. The lines are small, and you do not want to hit them with the drilling unit.
You typically can not drill between the tank and the building it services because you have the fuel lines from the tank running to the heater, as you do not want to hit them so that leaves data gaps. You also can't drill under the oil tank, the testing is not 100%, and that does not mean the tank will leak tomorrow.
If you have read this far, you have learned a lot. But hang on for one more tidbit of knowledge. Don't test the oil tank, remove and replace it or convert it to another fuel source. You see, if the tank is old (99% likely) the advice will be to replace it even after it is tested and passes, because it will eventually leak. 
