How long do water heaters last? When to repair and when to replace

A standard tank water heater commonly lasts around 8 to 12 years. Tankless units often last longer if they’re descaled on schedule. Where yours lands depends on your water, how hard the heater works, and whether anyone ever flushed it. Most parts on a water heater can be replaced, but once the tank itself leaks, replacing the heater is the only fix.

How can I tell how old my water heater is?

Find the rating label on the side of the tank, the one with the model and serial numbers. Most manufacturers build the manufacture date into the serial number. Often it’s a couple of digits for the year plus a letter or number for the month or week. The format varies by maker and some have changed theirs over the years, so don’t guess.

To decode it, check the manufacturer’s website or call their customer line with the serial number handy. Some labels just print the date outright. Installers sometimes write the install date on the tank in marker, too. And if the heater came with a house you bought, check your inspection report. Inspectors usually note the age.

Which problems are worth repairing?

On a heater with plenty of years left, fixing these parts makes sense.

• Heating elements and thermostats on electric heaters. These are the most common electric repairs.
• The thermocouple, flame sensor, or igniter on gas heaters. If the pilot won’t stay lit or the burner won’t fire, it’s often one of these.
• The gas control valve. It’s a bigger part than a thermocouple, so the heater’s age starts to matter more here.
• The anode rod. It’s a metal rod inside the tank that corrodes so the tank doesn’t have to. Swapping a worn one can help a sound tank last longer, and it’s also a common fix for hot water that smells like rotten eggs.
• The T&P relief valve. A leaking or worn one can be replaced. Just have someone find out why it was opening first.

When is it time to replace it?

• The tank itself is leaking. Rust-through can’t be repaired. Read water heater leaking from the bottom to make sure it’s really the tank and not a valve or fitting.
• You’re getting rusty water from the hot side only. If the cold runs clear and the hot comes out brown, the inside of the tank is likely rusting. If both are rusty, look at your pipes or the water supply instead.
• It’s old and keeps needing repairs. A heater past ten years that has needed a couple of fixes lately probably has more coming. Putting more parts into it rarely pays off.
• It can’t keep up anymore, and a bad part isn’t the reason. Heavy sediment takes up room in the tank, and sometimes a household just outgrows the heater it has.

Age alone isn’t a reason to rip out a heater that’s working fine. But an old heater with a problem is a different conversation than a five-year-old heater with the same problem.

Why it pays to plan ahead

Most water heaters get replaced in a hurry. The tank lets go on a Tuesday night, and by Wednesday somebody’s buying whatever’s in stock that fits the space. That’s the worst time to make the decision.

If your heater is getting near the end of that 8 to 12 year range, start thinking about it now. Decide whether you want the same kind again or want to look at tank vs tankless, and whether the size still fits how your household uses hot water. Look at where it sits, too. A heater in an upstairs closet or over finished floors with no drain pan is a bigger risk than one on a garage slab.

If you plan it, you get to pick the day and compare options without water on the floor.

Do you need a permit to replace a water heater?

In most cities, yes. Replacing a water heater usually needs a plumbing permit, and gas units can bring gas and venting inspections along with it. Rules vary by city and county, so check with your local building department or ask whoever’s doing the work if they’re pulling the permit.

The new heater has to meet current code, which may have changed since the old one went in. Things like the relief valve discharge line, expansion tank, venting, and drain pan can all come up. And an unpermitted install can turn into a question when you sell the house.

If you can’t tell whether yours is worth fixing, call us. We’ll tell you straight and give you a price before we touch anything.