Finding out you have an underground oil tank on your property can quickly turn into a headache when you consider Ontario’s strict oil tank regulations. Ontario’s regulations are in place to ensure the safety of the public as well as the environment, as oil tanks are prone to leakage over time. But what causes an underground oil tank to leak in the first place?
As experienced underground oil tank removers and remediators, the professionals at Waterline Environmental get this question all the time, so let’s review some of the reasons that can cause an underground oil tank to spring a leak.
We previously discussed what exactly oil tanks are and why some people will find them buried on their properties. The reason is that oil tanks were a common fuel source to heat homes throughout the mid to late 20th century. That means that any underground oil tank remaining on a property today has likely been there for quite some time, and as we know, time isn’t always our friend.
With an oil tank’s average life expectancy of roughly 20 years, the more time that passes beyond that, the more susceptible the tank is to decay and damage from elements inside and outside of the tank itself.
What causes corrosion and decay of the tank’s steel walls?
The surrounding soil
Certain types of soil have a higher salt content and acidity level than others, which causes the decay of the tank’s metal walls over time.
Water and sludge inside the tank
When there is space for air in an oil tank, humidity in the surrounding environment can cause condensation. The water becomes a breeding ground for bacteria while the oil feeds and houses microbes, forming a sludge that settles at the bottom of the oil tank. This sludge is both corrosive and acidic and eventually eats through the tank’s metal walls, causing a leak.
As mentioned previously, there should not be too much space for air in an underground oil tank; otherwise, humidity and condensation will corrode the tank from the inside out.
On the flip side, a tank should also not be overfilled. The sweet spot is keeping the oil tank filled to around 80% capacity.
Overfilling an oil tank can cause fuel to back up through the fill pipe and spill out. You also want to ensure there is enough space in the tank to account for expansion when temperatures rise. This is because fuel expands when it is heated, and a warmer temperature, as we see in the summer months, will lead to some fuel expansion.
Lack of maintenance
It goes without saying that not maintaining an underground oil tank will lead to faster deterioration of the tank and, eventually, oil leaks.
Having an oil tank inspected by professionals yearly will help prevent and catch any ongoing decay and spillage, ensuring the tank is in good enough condition to keep its contents safely stored and out of the surrounding environment.
Without regular inspections, it’s anyone’s guess as to whether there is an oil leak since the tank is underground and out of sight, but it could be negligent to assume that an old underground oil tank unit would be free of any cracks, pinholes and leaks. That’s why it’s recommended that they are replaced if they are 15 years of age or older.
Of course, the simplest way to maintain an underground oil tank is just to have it removed entirely!
With winter months and cold weather comes the dreaded freeze-and-thaw cycle. This cycle causes the soil around an underground oil tank to expand and contract. This ground movement can damage the older piping attached to an underground oil tank, resulting in oil leaks.
Below-zero temperatures can also cause cracks in the risers on the tank that will then allow water to seep in, and we already know the damage water can do when it gets into an underground oil tank.
Not sure if you have a leaking oil tank underground? Here are four ways to spot a leak.
Protect yourself and the environment from the dangers of underground oil tank leaks by contacting Waterline Environmental!
Contact Waterline Environmental
President: S.A. (Stu) Ferguson