Do you know how deep heating oil tanks are buried? You might be thinking… “The depth doesn’t matter to me.” Well, it matters, especially if you are planning to do any major landscaping or planting. You also need to know the depth if you’re planning to install new utility lines such as natural gas, propane, electric, water irrigation/sprinkler, or phone and cable lines. Know how deep your oil heating tank is.
It is important to know how deep the tank is buried, where the tank’s ends are, and where the copper oil supply and return lines are located. “Why is this important,” you ask?
If you or a contractor plans to dig onsite by hand or with a trench machine, the copper oil lines could be clipped, cut, or punctured. Even if this process doesn’t obviously cut the lines, it can puncture the lines unknowingly, causing a huge problem.
What Happens if My Oil Line Punctures?
As you run your heat or hot water, some oil may leak out of the copper lines into the ground, contaminating the soil, basement, well water, or a neighboring property. This means you get to spend more to fix it. You may not know you have a problem until your furnace or boiler start showing signs. You may also see or smell oil inside the house, which is a safety concern.
How Deep Should My Oil Tank Be?

On average, most buried oil tanks in Maryland have about 2 to 3 feet of dirt on them – that’s what we call “cover”, the measurement to the top of the tank. Consequently, the copper oil lines are even shallower, as they almost always come off the top of the tank to go into the house. While 2 feet is the average “cover”, the depth can range from 0 to 7 feet. Zero meaning that the top of the tank is exposed and sticking out of the ground or perhaps only has a few inches of dirt on top of it.
At the extreme opposite end would be 7 feet of cover. While this is by no means typical, GreenTrax Inc has seen a few tanks with anywhere from 5 to 7 feet of dirt on top of them. But most commonly, you will find the TOP of the tank buried less than 4 feet deep. Again, the most common depth is 2 feet.
Know How Deep Your Tank Is
Unless you are planting flowers, any other digging or excavation you do should be done with care because the tank or oil lines could be punctured.
Also, depending on the tank’s size, the tank’s BOTTOM would be anywhere from 3 feet deep to 9 feet deep. If you have a smaller tank, the diameter will be smaller, and the bottom depth shallow. The opposite is true for larger tanks. If you have a large tank, the diameter will make the bottom depth deeper.
Why You Should Act Now

If you are doing any construction within the tank’s location, the first thing we would ask is what and why? You do not want to be building a driveway, new patio, or installing new concrete or brick pavers over top of the tank.
You also DO NOT want to be installing new natural gas, propane, sprinkler, cable, telephone, or electric lines over the top of or right next to a part of the tank. The tank need to be removed or abandoned by an MDE licensed tank removal contractor first!
Why?
Let’s say you let the utility company install a natural gas line over the tank’s top and it is done in a way that the tank cannot be removed. We cannot dig out contaminated soil, and the Maryland Dept. of the Environment requires additional work.
In addition, if you decide to sell the house and hire tank removers to remove the tank and they find out that the tank is leaking, this can delay or halt the home sale and prolong the process unnecessarily.
So the bottom line is this… If you have an active tank that you use or unsure if you have one but have an oil tank fill pipe, a vent pipe, or copper lines in your basement, get it checked out first. If you install the brand new expensive patio or home addition over top of the tank, it WILL come back to bite you later.
Also, if you have a buried tank you are NOT using anymore, do not delay. Get the tank removed now to avoid issues in the future. Waiting can cause you more money and more headaches later. Know how deep your oil heating tank is.