Many property owners with old and unused underground oil tanks ask Stormworks how you can tell if your oil tank has leaked. That’s a tough question with little chance of accuracy until the tank has been removed from the ground. On rare occasions, Stormworks has viewed liquid surface oil oozing from the ground. We have seen 2 or 3 cases like this in over 14 years of tank removal in Greater Vancouver.
Large industrial or commercial sites where contamination is suspected can be drilled to identify the scope of contamination and how far it has traveled . Most drilling options are not cost effective for single residential tank situations.
Surprising to many customers most oil tanks haven’t leaked, and those that have are statistically of the smaller variety. Certainly oil tanks do leak and some cleanups are substantial in size. The very large remediations are the ones that garner media attention and become part of oil tank folklore.