Step 1: Turn off the heat
On a gas heater, turn the control dial to “Off” or “Pilot.” On an electric heater, switch off its breaker. This keeps it from heating a tank that may be draining.
Step 2: Shut off the cold water
Close the cold water valve on the pipe at the top of the heater. If you can’t find it or it won’t turn, shut off the main water valve to the house.
Step 3: Find where it’s coming from
- Top of the heater: often a loose fitting, a leaking connector or the relief valve. Usually repairable.
- Relief valve pipe: the temperature and pressure relief valve is releasing water. This can mean high pressure or a worn valve.
- Drain valve near the bottom: a valve that isn’t fully closed or has worn out. Usually repairable.
- The tank itself: water seeping from the bottom of the tank or through rust. The tank has failed and needs replacing.
Tip: Water on the floor isn’t always from the heater. Check nearby pipes and the washing machine before deciding.
Step 4: Protect the area
Move anything that can be damaged, mop up standing water and put down towels. If the leak is heavy, keep the water off until a plumber arrives.
Repair or replace?
Leaks from fittings, connectors, the drain valve or the relief valve can usually be fixed. A leak from the tank body can’t. If the heater is also 10 to 12 years old or more, replacement is the better value.
Never plug the relief valve
The temperature and pressure relief valve is a safety device that keeps the tank from building up dangerous pressure. If it’s dripping, have it checked. Don’t cap or plug it.