[goshenplumber]

Our heating system uses an underground 1,000 gallon heating oil tank. I have a question about potential tank leaks. My understanding is that if there was a leak it would happen as either:
(1) Oil leaking out of the tank
(2) Ground water leaking into the tank

Question:
Is there any other mechanism that could occur?
Could both (1) and (2) be happening simultaneously? I would not think so.

Note: Every summer, I test the tank using EPA standard 510-B-93-005 ("Manual Tank Gauging for Small Underground Storage Tanks"). The test uses a pair of tank level readings each week for 4 weeks with individual tank level readings within a pair taken at least 58 hours apart. My tests have never detected a leak.

Comments?

 

[beenthere]

Usually if oil is leaking out and water leaking in. They don't happen at the same rate.

The supply oil line going into the tank for the pump to pump the oil out of the tank and into the nozzle. Is seldom more then 3" above the bottom of the tank. So if you had water leaking into the tank. You generally would have water in your nozzle so the burner wouldn't work.

Oil leaking out is the greater concern. So a double check, would be to compare oil consumption from year to year, based on heating degree days for each year. The amount of oil, should match fairly close in percentage to the number of heating degree days for each year.

EG:

Year 1, 5200 HDD 950 Gallons
Year 2, 5149 HDD 940 Gallons
Year 3, 4800 HDD 877 Gallons
Year 4, 5450 HDD 1175 gallons. This one would indicate oil leaking out of tank, or you set the thermostat higher then in previous years, as it should have been closer to 995 gallon.