Water Heater Leaking: What to Do Right Now, Step by Step

If your water heater is leaking, turn off its heat source first, then stop the water. For a gas heater, turn the control knob on the gas valve to OFF; for an electric heater, switch off its breaker at the panel. Next, close the cold-water shutoff valve on the pipe at the top of the tank. That stops new water flowing in and makes the heater safe to inspect. Then find the leak: a loose fitting or drain valve can often be fixed, but a leak from the tank itself means the heater has to be replaced.

Work carefully. The water inside can be hot enough to scald, and the area around a heater often has electricity and gas close together.

Step 1: Shut off the heat source

Gas water heater

Find the gas control valve on the front of the tank near the bottom. Turn the knob to OFF. Bob Vila's guide says to turn the dial to the off setting near where the gas line connects. For extra safety, you can also close the gas supply valve on the pipe leading to the heater (the handle is closed when it is crossways to the pipe).

If you smell gas, do not touch switches or try to relight anything. Leave the house and call the gas utility from outside. FEMA's flood repair guide gives the same advice for any suspected gas leak.

Electric water heater

Go to the breaker panel and switch off the breaker labeled for the water heater. Do this from a dry spot. If water has reached the panel or you would have to stand in water to reach it, stay out and call an electrician or the power company.

Turning off the heat matters even if you plan to drain the tank: an electric element running in an empty tank can burn out, and Family Handyman advises turning off the gas or electricity and letting the water cool before you work on the heater.

Step 2: Close the cold-water valve

On top of the heater there are two pipes. The cold-water inlet usually has a shutoff valve just above the tank. Turn it clockwise until it stops, or a quarter turn if it is a lever. If that valve will not close or is leaking itself, close the main water shutoff for the house.

Step 3: Protect the area

Mop up, move stored items away from the heater, and put towels or a shallow pan under the drip. If water has already spread across a finished floor or into drywall, the clock is running: the EPA says water-damaged areas should be dried within 24 to 48 hours to prevent mold.

Step 4: Find where it is leaking

Check from the top down with a flashlight and dry paper towel. Bob Vila lists the three usual spots as the fittings on the pipes above the heater, the drain valve near the bottom, and around the temperature and pressure relief (T&P) valve.

Leaking T&P valve

The T&P valve is a safety device. It opens to release water if the tank gets too hot or the pressure gets too high. Family Handyman warns that a leaking T&P valve could indicate dangerously high pressure in the tank. Bob Vila suggests lowering the thermostat and testing the home's water pressure with a gauge. The Department of Energy, cited by Bob Vila, says 120°F is hot enough for most homes.

Never cap, plug or remove the T&P valve or its discharge pipe. If it keeps releasing water, have a plumber check it.

Leaking drain valve

Family Handyman says sediment can collect in the drain valve housing so it does not close fully. Tightening it with a wrench may stop the drip. A brass cap on the hose thread is a short-term fix, and replacing the valve is the longer-term one.

Leaking tank

If water is coming from the tank body or from under the jacket at the bottom, the inner tank has corroded through. Bob Vila says bottom-of-tank leaks require replacement, and if the heater is more than 10 years old the leak is likely age-related. Do not try to patch it.

Step 5: Drain the tank if it is failing

If the tank itself is leaking, draining it limits how much more water ends up on the floor. With the heat off and the cold-water valve closed, let the water cool, then:

1. Attach a garden hose to the drain valve and run it to a floor drain or outside, lower than the valve.
2. Open a hot-water faucet somewhere in the house to let air in.
3. Open the drain valve slowly.
4. Keep the hose end where hot water cannot splash anyone.

If the drain valve is clogged with sediment, the tank may drain very slowly. Leave it for the plumber rather than forcing the valve.

Step 6: Decide who to call

• Plumber: to repair a fitting or valve, or to replace the heater. Bob Vila notes replacement usually needs a licensed professional because of local building codes for gas and electrical connections.
• Restoration company: if water has soaked carpet, drywall, subfloor or a finished basement. Wet materials need extraction and drying, and moisture meters to find water you cannot see. See water heater leak cleanup.

Many homeowners need both: a plumber for the heater and a restoration crew for the floor and walls.

Will insurance pay?

Triple-I's guidance says the HO-3 covers accidental discharge of water from a plumbing system. In practice, sudden water heater failures are often covered for the water damage they cause, while the worn-out heater itself usually is not, and slow leaks are treated as maintenance. Read does homeowners insurance cover water damage and keep photos of the tank and the damage. If the water reached the basement floor, the flooded basement guide covers safe cleanup.

How to avoid the next one

• Triple-I recommends replacing any cracked or leaking hoses immediately, and replacing water heater, washer, dishwasher and icemaker hoses every five to seven years.
• Put the heater in a drain pan piped to a drain.
• Flush sediment as the manufacturer recommends.
• Note the install date on the tank and plan replacement as it ages past 10 years.

The water damage restoration cost guide shows what drying and repairs typically cost if the leak got ahead of you.

If water has spread past the heater, one free call connects you with an independent local restoration company. Lines are open 24/7, there is no obligation to hire, and the company can tell you on the phone what to do until the crew arrives.