Underground Storage Tanks (UST)
For over 60 years Canadians have used USTs to store heating oil. These tanks vary in size from 200 and up to 1000 gallons. Because aboveground tanks were considered unsightly they were often buried. Unfortunately many of these tanks were not built to resist decades of corrosion and consequently developed holes. Oil being less dense than water will be pushed out of the tank by water levels rising and displacing the oil. Because they are out of sight the problem was often not detected.
This is why underground tank removals make sense.
Houses built between 1950-1970 could have UST.
Residential Oil Tanks are between:300gal-650 gal
Commercial Oil Tanks are between:1000gal-4000gal