Whether inside, outside or underground, oil tanks have all become an issue at house sale time. Oil tanks always accompany any type of oil burning appliance (furnace, hot water tank). If you have an oil appliance there is inevitably a tank. They can be found outside, inside a basement or underground. However, homes that have had the oil-burning appliance removed might not have had the oil tank removed, which could cause problems. Tank manufacturers and installers put the normal life expectancy of a tank at between 20-30 years, but failures have occurred in tanks as little as 10 years old.


About Underground Tanks

Underground tanks became an issue for homebuyers, sellers and realtors in the last 10 years. The existence of an underground tank once discovered generally results in redemption prior to ownership transfer. Underground tanks are not always obvious, but if spotted warrant further investigation. Homes built in the 1960’s and earlier could have abandoned underground tanks. Underground tanks must be rendered inert (non-polluting) once they are discontinued. Typically this means pumping out the contents and filling with gravel or sand to prevent sinkholes once the tank rusted out.
Tanks with oil still or contaminated water in them pose a bigger problem as they have to be pumped out – the water or oil is then treated as contaminated waste and can be expensive to remove from your property safely. If oil has leeched out into the soil, this can be a major expense as the tank may have to be dug out along with the contaminated soil and sent for decontamination.


Above-Ground Tanks – Interior and Exterior

While far fewer above-ground tanks have leaked than underground tanks, insurance companies see them as a hazard due to the shear number of these tanks throughout the country. An informal survey of insurance companies reveals that in general, insurers will accept above-ground oil tanks up to 20 years old, but if needed the cost of removing an above ground oil tank is usually around the $100-200 range. Of course, if the tank leaked costs can skyrocket depending on the level of contamination.


How Old Is Your Tank?

Determining the age of a tank is difficult at best because dated identity plates were not used until 1997. From 1984-1987, some tanks were banded on the top lift loop, but other than that dating is inconclusive. In general, 6’ long tanks, tanks with a half moon or double vertical crease on the end panel and “Western Steel” stamped on them are all over 30 years old and ready for replacement. However, lack of these indicators does not necessarily mean it is newer.
A good source of information on tank age is often found in the building records, usually at city hall. Newer tanks are installed under a building permit, so depending on the reliability of the municipal records, a new tank installation may show up there. If you can’t find the record there, you can take a reasonable guess the tank is original and may be older than the 20 years that insurers accept.
If the tank’s age cannot be verified, insurance companies may not be interested in your business until the tank is replaced. While it might seem like a burden, replacing older oil tanks has a reasonable cost when compared to cleaning up a spill and contaminated soil. Most oil tank companies will have up-to-date information on costs involved in both replacing non-leaking and leaking tanks.