How long do water heaters last?

Key takeaways

• Tank water heaters last about 10 to 15 years. The U.S. Department of Energy's Energy Saver guide (2022) says most storage water heaters last 10 to 15 years, while tankless water heaters can last more than 20.
• Age is a range, not a deadline. Water, use and upkeep change the number.
• The warning signs are rust-colored hot water, rumbling or popping noises, water around the base, and lukewarm water.
• A leak from the tank itself usually means replacement, not repair.
• Replace on your schedule, not in an emergency. A tank near the end of its range is worth planning for before the first hard freeze.

How long a water heater lasts

The most reliable number comes from the U.S. Department of Energy. Its Energy Saver guide (2022) says most storage water heaters last 10 to 15 years, while tankless water heaters can last more than 20. That is a range for the whole country. Your own heater may last less or more.

What shapes the number:

• The water. Minerals in the water build up as sediment in a tank or scale in a tankless heat exchanger, and both shorten life.
• How much hot water the house uses. A large household works a heater harder than a small one.
• Upkeep. A tank that gets regular attention tends to outlast one that never does. Tankless units in particular depend on being descaled.
• Where it is installed. A heater in a conditioned space is easier on its parts than one in a damp crawlspace or unheated garage.

A tank heater stores water, so a rusted tank can leak. A tankless heater has no tank to rust through, which is one reason it can last longer, but it has more electronics and a heat exchanger that needs care. See tankless water heaters for how they work.

How to find your heater's age

Check the label on the side of the tank. It lists the model number, the serial number and the capacity. Many manufacturers build the date of manufacture into the serial number, but each one uses its own format. If you can't read it, ask the manufacturer's customer service or a plumber. Also look for a sticker or note from the last installer, and the date on a past receipt or a home inspection report.

Write the age down, and take a photo of the label so the model and serial number are on your phone when you call a plumber. If you are buying a house, the heater's age is one of the first things to ask about, along with the date of its last service.

Signs a water heater is near the end

These are the signs plumbers look for:

• Rust-colored hot water. If the cold taps run clear and the hot taps run orange or brown, the tank may be corroding from the inside.
• Rumbling, popping or knocking from the tank. Sediment on the bottom can trap water that boils and bubbles through it.
• Water around the base. A leak from a fitting or valve may be repairable. A leak from the tank body is not.
• Lukewarm or inconsistent water, or hot water that runs out much sooner than it used to.
• Frequent repairs. A heater that needs a part every few months is telling you something.
• Age. A heater at the upper end of its range deserves more attention.

If you have a gas heater, a pilot that won't stay lit or a flame that looks wrong needs a professional. If you smell gas, leave the house and call your gas utility from outside. See gas water heater repair. For an electric heater that has gone cold or trips a breaker, see electric water heater repair.

Repair or replace? A rule of thumb

There is no single answer, so treat this as a rule of thumb and not a promise.

1. A young heater with a failed part is usually worth repairing. Elements, thermostats, thermocouples and relief valves are common, modest repairs.
2. A heater in the middle of its range with a part failure deserves a conversation. Ask the plumber how likely other parts are to fail soon.
3. A heater near the end of its range with its first real problem is a candidate for replacement, because the repair may buy only a little time.
4. A leaking tank means replacement. A tank can't be patched safely.
5. Rusty water from the hot side only points to the tank, which is a replacement conversation.

Ask the plumber to write down both options with the work each includes, so you can compare. The water heater repair page explains what repairs involve. If replacement is the answer, water heater replacement explains the process. For what the work can cost, with sources and dates, see plumbing costs.

Upkeep that helps a heater last

Follow the manufacturer's manual first. It tells you what your model needs and how often. In general:

• Flush the tank periodically to remove sediment, if the manual says to. A heater that has never been flushed may need a plumber's help, because old sediment can clog a drain valve.
• Check the anode rod. The rod inside a tank is designed to corrode instead of the tank. Plumbers check it every few years and replace it when it is mostly gone.
• Test the temperature and pressure relief valve as the manual directs. It is a safety device.
• Descale a tankless heater on the schedule the manufacturer gives.
• Keep the area clear. Nothing flammable should be stored next to a gas heater, and the vent and combustion air must stay open.
• Look at it often. A glance at the base and the pipes every few months finds small leaks early.

If it fails before you are ready

A failing tank rarely gives a warning that fits your schedule. If water is leaking from the tank, do these in order:

1. Turn off the power or the gas to the heater. For an electric heater, use the breaker. For a gas heater, use the gas control or the shutoff on the gas line, and leave the house if you smell gas.
2. Close the cold-water supply valve on the pipe feeding the tank.
3. Open a hot tap somewhere in the house so the tank isn't under pressure.
4. Move anything that can be damaged away from the water, and take photos.
5. Call a plumber. If a lot of water has spread, see water damage restoration.

When you are choosing a replacement

A replacement is a chance to rethink the heater, not just swap it. Questions worth asking the plumber:

• Which fuel and type fit the house? Gas and electric tanks, tankless units and heat pump models all behave differently.
• What size do we need? A heater that is too small runs out of hot water, and one that is too large wastes energy.
• Does the venting, gas line or electrical circuit need changes? Those extras are often what separates one quote from another.
• What does the warranty cover, and who handles a claim?
• Who pulls the permit, if one is needed?
• What happens to the old heater?

Plan around winter

Heaters tend to show their problems when they work hardest. In East Tennessee, the typical last freeze of spring at the Tri-Cities Airport is around April 16, based on 1991 to 2020 data from NOAA and the National Weather Service. If your heater is near the top of its range, a planned replacement in the fall is easier than a weekend emergency.

If a heater fails, shut off the cold-water supply to the tank and the power or gas to it, and call a plumber. The emergency plumber page explains what counts as an emergency.

When to stop and call

Call a licensed plumber when:

• Water is leaking from the tank itself.
• You smell gas, or a gas heater's flame looks wrong. Leave the house first.
• A breaker keeps tripping when the heater runs.
• The relief valve is dripping or discharging.
• The heater is making loud noises or the water is rusty and the heater is old.
• You aren't sure what you have.

Safety

• Gas. If you smell gas, leave the house and call your gas utility from outside.
• Electricity. Turn off power at the breaker before any work on an electric heater, and never work near it with wet hands or while standing in water.
• Hot water. Water at high temperatures can scald. Follow the manufacturer's temperature guidance.
• Weight. A full tank is heavy. Don't move one alone.