How long should a 275 gallon oil storage tank last?

I will add that now is a good time to start thinking about what you want to do when the tank does start leaking. I had been thinking about converting the oil burners in our boilers to natural gas for $$ savings. Obviously, the potential savings depends on the relative prices of the two fuels. Some people near natural gas fields in, say, Pennsylvania can get ridiculously cheap natural gas. Here in the Boston area, it's more expensive, but it would still be less costly than burning oil.

As it turned out, I couldn't find any local heating companies who would do the conversion, despite the fact that it's a relatively simple process. But other people on this site have done it, easily, with good results.

If we had been able to convert to gas, the time to do it would have been when we replaced the tanks. Because the tanks cost us more than the list price of an entirely new boiler (we're not allowed to say exact $ figures on this site).

Another option is heat pumps, which are getting more and more efficient.

So if you think you'd like to continue with oil heat, fine. But if not, make a plan now and be ready to pull the trigger if/when your oil tank starts leaking.

@RTW The good news is that oil tanks seldom just start gushing oil. They usually start to seep a little bit. Just check the bottom of the tank a couple of times a year. Your bound to have a little surface rust which is no big deal.

How old is the house?

Anecdotal:

A 275 horizontal tank in the basement lasted 36 years and developed a drip from the bottom. Lost an estimated 5 gallons to the floor before I discovered it.😖

I have two 275 verticals in another location that are an estimated 55 years of age.

Also anecdotal:

The horizontals have a single feed to one of the tanks (the one that failed) and a crossover.

The verticals at the other location fill independently.

I ponder the higher pressure in the first horizontal during a fill a 60 GPM during the crossover. I have now resorted to requesting a slow fill from 200-300 (my typical ordering quantity).

This is what we have. Two tanks, two fill pipes.

If it's a steel tank, you can't see the damage because it's on the inside. If it's set up like @Big Ed_4 said, you should be ok. Maybe think about tank treatment. It's not going just let go. It'll weep. That's why you always have those baking tins lying around.

I replaced my tank this Spring. During a scheduled annual furnace tune-up I asked the tech about the age of oil tanks and the recommended upgrade age. He looked at the 275 gallon tank info on the tank label and discovered that it was 53 years old. The company recommended a change out after 30 years……probably real comservative…..but the cost of remediation for a leaking tank would be alot more. I got a double walled 265 gallon tank installed for $,$$$. That included the new tank, transferring the 200 + gallons from the old to the new tank, disposing of the old tank and upgrading the plumbing to the self priming device and confirming proper furnace operation. That included extending the fill and vent ports to the outside of the building for easier access.

We already have gas piped into the basement for our water heater, and I found a local heating contractor who said he had done the conversion in his own home and it was relatively simple. Unfortunately we weren't regular customers and he was too busy taking care of them to do our conversion.

If you already have a gas line in the basement, it is not that hard to do.

The old-type steel oil tanks corrode from the inside out. Invariably water finds its way in, usually via condensation. At the interface of the oil and water, a microbe colony can establish itself; they feed on the hydrocarbons and get their oxygen for metabolism from the water. As the microbes die off, they settle to the bottom and form an acidic sludge, which attacks the steel from the inside. Usually, leaks show up as "wet spots," but occasionally a tank "lets go" and you have a real environmental catastrophe on hand. I wouldn't recommend waiting for that to happen. Also, the sludge doesn't work wonders for the burner, and if equipped with the old-type cartridge filter, inevitably finds its way to the fuel unit. Have your contractor install a Roth double-wall tank, along with a de-aerator and flex hoses to the burner (cuts down on labor when servicing the boiler by allowing the burner door to swing open without disconnecting/reconnecting the fuel piping). Also, the fuel filter assembly should be changed to the much more effective spin-on type filter. Hope this helps…