When to Replace a Water Heater

Replace a water heater when the tank itself leaks, when it's past about 10 to 12 years old and needs an expensive repair, or before it fails in a spot where a leak would do real damage. Here's how to tell which situation you're in.

By Suraj Jha · Updated 2026-10-22

The short answer

1. Start with age

Age is the best single predictor of how close a tank is to failing. Most tank water heaters last 8 to 12 years, and tankless units 15 to 20 years or more (see how long water heaters last). Find the age on the rating label: some print the date outright, and the rest encode it in the serial number. Our lookup tool decodes it.

As a tank passes about 10 years, every year adds a bit more risk of a leak. That doesn’t mean it will fail tomorrow, but it does mean you should know what you’ll do when it does.

2. Look for warning signs

• Water under or around the tank. Find the source. Drain valves, relief valves and fittings can be fixed. A tank leak can’t.
• Rusty hot water. If the cold water is clear and the hot isn’t, the tank or anode is corroding.
• Rumbling or popping. Heavy sediment. A flush may help on a younger tank; on an older one it often signals the end is near.
• Running out of hot water. Could be a failed element or thermostat (repairable), a broken dip tube (repairable) or sediment filling the tank (a sign of age).
• Corroded connections on top of the tank, or rust under the jacket.

3. Weigh repair against replacement

Common repairs on a tank water heater are usually modest: thermocouples, flame sensors, heating elements, thermostats, relief valves and drain valves. Gas control valves and the sealed combustion parts on newer gas tanks cost more. A simple rule:

• If the tank is under about 8 years old, repair almost anything except a tank leak, and check the warranty first.
• If it’s 8 to 12 years old, repair cheap parts but think twice about anything costing more than about a third of a new installed heater.
• If it’s over 12, a big repair rarely makes sense.

4. Think about where the tank is

A tank in a garage, next to a floor drain, can be run until it shows symptoms with little downside. A tank in an attic, a closet next to a bedroom, or a finished basement is a different story. When tanks fail they can release their whole contents, and keep releasing water, so the cost of a leak can easily exceed the cost of a new heater. In those spots, replacing proactively around the 10 to 12 year mark is the safer bet. A drain pan with a drain line, or an automatic leak shutoff valve, adds protection either way.

5. Choose the replacement before you need it

Shopping during an emergency means taking whatever the plumber has on the truck. If your heater is in the replacement window, compare options now:

• Same type, same size: the cheapest and fastest swap.
• Heat pump (hybrid) water heater: uses far less electricity than a standard electric tank. It needs space and air around it, and a condensate drain. Utility and state rebates are often available; check what currently applies in your area.
• Tankless gas: endless hot water and a longer life, but higher upfront cost. It often needs a larger gas line and new venting.
• Bigger or smaller tank: if your household has changed, resize. A tank that’s too big wastes energy keeping water hot; one that’s too small runs out.

Before the plumber arrives

• Note the brand, model and serial number from the label, plus the fuel type and capacity.
• Check the age with our lookup, and whether the tank is still under warranty. Some manufacturers will supply a replacement tank, though you’ll typically pay for labor.
• Make sure there’s clear access around the heater.
• Ask whether the quote includes the permit, haul-away, an expansion tank, a new drain pan and code updates such as seismic straps where required.