Water heater leaking: what to do, maintenance and lifespan

Checked against FEMA and other official sources · Last reviewed October 8, 2026

What to do right away

• If you smell or hear gas, get out. CPSC says to "leave your home immediately and contact local gas authorities from outside the home," and not to operate lights, phones or other electronics before leaving.
• Turn off the heat source. Portland's water bureau says to "always turn off the heating elements before doing maintenance on your water heater." An electric heater can be shut off at the breaker box (Montana State University Extension). On a gas heater, Canton Township, Michigan's flushing guide has you set the gas control valve to the "pilot or off" position.
• Close the cold water inlet valve. This valve is on the pipe that feeds cold water into the tank. NYSERDA, New York's energy agency, says that if the relief valve won't stop releasing water, "immediately disconnect the electrical power, close the cold water inlet valve and call a qualified plumber."
• If water is still spreading, shut off the main. The Texas Department of Insurance says, "If you have a sudden leak, shut your water off at the main," and move expensive items off the floor.
• Keep your distance from a leaking tank. The Town of Northlake, Texas, says that if you suspect a leak inside your water heater, "call a plumber immediately and keep your distance in the meantime. Tampering with a water heater can be dangerous."

Never touch a wet appliance that is still plugged in, CPSC warns. [1][2][3][5][6][7][11]

Where is the leak coming from?

City utility guides from Duncan, Oklahoma, and Northlake, Texas, give the same checklist: - Look for water pooling on the floor by the heater or in the overflow pan. "Many times, the cause is a dripping valve that needs to be replaced." - Find the pressure relief valve near the top and the drain valve near the bottom. Listen for "dripping, gurgling, or hissing sounds." A tank can leak inside before you see water outside. - If the valves are dry, "there's a chance the leak is inside the tank, which means you may need a new water heater."

Other common sources: - Relief valve dripping. Portland says the valve may need replacing, or you may need an expansion tank. In rare cases, Portland says, there could be a pressure problem in the city's water system. - Drain valve dripping. Canton notes that the washer in the drain spigot can wear out and may need replacing if it drips after closing. - Rusty water or a leaking tank. Portland says this can mean the sacrificial anode no longer works, "which can lead to tank corrosion or failure." [3][4][6][7]

The temperature and pressure relief valve

Montana State University Extension says gas and electric tank heaters both have a temperature and pressure (T&P) relief valve near the top of the tank. It explains that the valve "will allow steam or hot water to escape safely, should a thermostat malfunction occur." NYSERDA calls it "vital for keeping your water heater and your home safe."

Both say to check it once a year. NYSERDA's method: lift the lever to make sure the valve moves freely, then let go and make sure it closes. Before you do, "make sure no one is at risk of coming into contact with the hot water released."

If you add an insulating blanket to the tank, Montana State says: "Never cover the pressure temperature relief valve." [1][2]

How to flush a water heater

Sediment and minerals build up in the tank. Montana State says this reduces heating efficiency and capacity.

How often: Canton and NYSERDA recommend flushing annually. Portland says most manufacturers recommend it "every year or every few years." Montana State says monthly flushing is recommended in some hard-water areas, and once a year is enough in others. Follow your heater's manual.

Canton's steps for a gas tank: 1. Note where the gas control valve is set, then turn it to pilot or off. Canton warns that if the burner comes on while the tank is empty, "the heat will ruin the tank." 2. Shut off the cold water valve to the tank. 3. Open a hot water faucet to let air in, then drain the tank through a garden hose to a floor drain. 4. With the spigot open, turn the cold water on in 15-second bursts, letting it drain after each one. Three bursts should do it. 5. Close the spigot, turn the cold water back on until water flows steadily from the open hot faucet, then close the faucet and reset the gas control.

Canton warns that doing the steps out of order can damage the tank, pipes or floors, and that 30 to 75 gallons of hot water will be lost. For an electric heater, turn off the power at the breaker first.

A lighter option from Montana State: open the drain valve and let water run into a bucket until it runs clear, usually one to two gallons. [1][2][3][7]

How long do water heaters last?

Official estimates vary a little: - Portland says the typical lifespan is 10 years for a tank-style heater and 20 years for a tankless heater. - Vermont's state Energy Saver program says "an average water heater lasts about 10-15 years."

Vermont suggests replacing an old heater near the end of its life. That can save energy sooner and help "avoid a costly clean-up if your old unit fails."

The anode rod helps a tank last. NYSERDA says it "prevents your water heater from rusting away" and suggests checking it every 1 to 3 years. Check your warranty before doing this yourself. [1][7][8]

What temperature should a water heater be set to?

The Consumer Product Safety Commission (CPSC) "urges all users to lower their water heaters to 120 degrees Fahrenheit." Most tap water scald injuries and deaths are among older adults and children under five.

CPSC says most adults will suffer third-degree burns from 2 seconds in 150°F water, and burns also occur in 6 seconds at 140°F or 30 seconds at 130°F. Even at 120°F, a five-minute exposure could cause third-degree burns. Always hand-test bath water for babies and young children.

Portland gives a wider range, 115°F to 140°F. It says 135 to 140 degrees can prevent the growth of bacteria such as Legionella but can scald, so have a plumber install anti-scald devices if you choose it.

Before adjusting an electric heater, CPSC says to shut off its power at the breaker or fuse. For gas heaters, it says to call your gas company, because thermostats differ. [7][12]

Does insurance cover a leaking water heater?

It depends on how the water got out. The Texas Department of Insurance lists water heaters among common sources of household water damage. It says most home policies cover "sudden and accidental" water damage, and "it's not a leak that's been dripping for a long time." Texas also says most policies don't cover damage from gradual leaks or seepage, including mold.

• Report quickly. Washington's insurance commissioner says sudden leaks are usually covered if you report them quickly and follow your insurer's advice for fixing the leak. Texas says hidden water damage usually must be reported within days of when you first see it.
• Check for a water damage sublimit. Washington warns that some policies cap water damage below the policy's full limit, and lists a water heater among the sources of water damage.

Policies differ, so read yours or ask your agent. See homeowners insurance and water damage. [9][10][13][14]

If your water heater was flooded

Flood water is a different case. Texas notes that home policies don't cover floods. An NFIP flood policy's building coverage does include furnaces and water heaters, even in a basement, where coverage is otherwise limited, as long as they are installed in their working location. See what flood insurance covers.

Don't use a gas water heater that has been under water until it has been checked. CPSC says to have a professional or your gas or electric company evaluate your home, and replace all gas control valves, wiring, circuit breakers and fuses that have been under water.

To protect against future floods, FEMA suggests raising water heaters above the ground floor or considering a tankless unit. See how to prevent basement flooding. [5][10][15][16]

Questions people ask