Underground Oil Tanks
Underground oil tanks were never intended to be underground forever. Right now they’re out of sight – out of mind and that’s the problem. Life expectancy is supposed to be 20-25 years and the old ones need to come out. Interestingly enough, no laws say they have to come out. But if they’re leaking, they do – and the probability is HIGH.
Opposite of assumptions, the older the house, the least likely the tank will be leaking. The old tanks were extremely solid and built with thick walls. It is hard for the acidity of soil to penetrate those walls.
We mainly worry about the tanks in houses built in the 1960’s – 1970’s during the Vietnam War era. The US was sending steel to the military to help them build an arsenal. We didn’t create that same quality steel at home anymore and now they’re not doing well against the pressures of the environment.
Tanks actually leak from the inside out most of the time. As the oil/liquid gets used and the level gets lower, the walls inside the capsule begin to sweat (condensation forms). Water and oil don’t mix. Oil rises to the top and water sinks to the bottom. Water on steel over time begins to rust out the bottom of the inside of the tank are starts producing holes. The acidity of the soil eating away at the outside of the tank and water eroding away the inside of the tank is a perfect storm for us homeowners.
Asking the sellers to take the tank out of the ground isn’t unreasonable, as eventually, Mother Nature will do her thing and oil will leak into the soil and then into the groundwater or nearby reservoirs, etc. If you’re able to remove the tank early before any leaks, the cost isn’t crazy. Where the numbers get high is AFTER the leaks contaminate the soil and the EPA has to get involved.
Cost to Replace
Removing underground tanks that are no longer leaking can cost $1200-$2K on average. If the location is in a hard-to-reach area and digging will be difficult, expect more cost.
Here’s the kicker: if the tank is leaking, the cost rises significantly and could be tens of thousands of dollars. Once the contractor sees or measures the soil for oil they are mandated to report it to the EPA. The surrounding soil will need to be removed and cleaned. There will need to have 8 clean samples of soil presented to the EPA to get an OK. This process is NOT easy or simple. We used to just take the oil out, clean the tank, and fill it with sand or foam or rock and close it back up. Today, we realize the damage these tanks can cause and the preferable method is to just take them out of the ground.
Replacing an oil tank with a double-walled above-ground tank costs approximately $2300. The double-walled tanks solve the condensation problem, much like a double-walled thermos. The inside of the tank is also made of a material modeled after Tupperware – it doesn’t leak. Won’t rust. Won’t sweat. Roth is one brand and they are so confident that each comes with a transferable million-dollar warranty for 25 years.
Rebates are available, up to $1300 through the CT Energy Marketers Association website (below).
Above-Ground Oil Tanks
The life expectancy for above-ground oil tanks is 20-25 years, as well. Did you know you can visually identify when above ground tank might leak??
Tell-tale signs:
(Disclaimer: I’m not a home inspector. Seek their advice if you notice an issue.)
- Look under the belly. Is it starting to bulge? The top and bottom should be the same shape. It’s a sign the steel is starting to spread and thin out. The tank was never intended to hold the weight for over 25 years. It means the steel is starting to give way.
- Legs should be perfectly straight. If a small buckle starts to form, it’s on the verge of collapsing. If it buckles and the bottom hits, the tank will split open. That’s no good and very expensive to clean up.
- A white waterfall of corrosion seeping down the sides is also a sign your tank has seen its final days. It’s an acid-like substance eating away at the steel and will flow to the bottom of the tank. Again, the corrosion on the outside eats the bottom of the tank at the same time the rust on the bottom of the inside. A double whammy.
A real quick test to see if there are any active leaks: run a tissue under the tank to see if there are oil leaks.
Some more good information:
- Connecticut Energy Marketers Association CEMA): https://www.ctema.com/
- CT NORA Rebates for Heating Equipment and Tanks: http://www.upgradeandsavect.com/
- Order FREE Materials: https://www.oilheatpros.com/ct/get-materials/