First turn off the power or gas and close the cold water supply valve. Then find where the water is coming from. Leaks at the pipe connections, drain valve or relief valve can often be repaired. Water coming from the tank itself usually means it has corroded through and the heater needs replacing.
Reviewed by Ron Olsen, Master Plumber, certified in Washington
Where Water Heater Leaks Come From
- Loose inlet or outlet connections
- Fittings on top of the tank can loosen or corrode over time.
- Drain valve
- The valve near the bottom of the tank can drip if it isn't fully closed or its seal has worn.
- Temperature and pressure relief valve
- This safety valve releases water when temperature or pressure is too high, or when the valve itself is failing.
- Corroded tank
- Sediment and rust eventually eat through the inner tank. This cannot be repaired.
- Condensation
- Gas units can drip condensation when cold water first enters the tank. This is not a leak and usually stops as the water heats.
What You Can Safely Check
- Turn off the power at the breaker, or set the gas control to off or pilot.
- Close the cold water inlet valve.
- Dry the area and trace the water back to its source.
- Gently tighten a loose drain valve cap or fitting. Don't force fittings on an old unit.
- If the bottom of the tank is leaking, drain the tank through a hose to prevent more water damage.
When to Call a Plumber
Call a plumber if the tank is leaking, if the relief valve keeps discharging, or if you can't trace the leak. A discharging relief valve can be a sign of dangerous pressure or temperature, so never cap or plug it.
The repair is usually part of water heater repair & replacement, which explains what the plumber does and what affects the cost.
Water Heaters by City
What our city pages say about water heaters:
- Boulder, CO: Homes from the 1960s and 1970s are on their third or fourth tank.
- Richmond, CA: Older tanks often lack current strapping and venting.
- Rochester Hills, MI: Homes from the 1980s and 1990s are on their second or third tank.
- Vero Beach, FL: Salt air shortens the life of tanks and fittings on the island.
- Allen, TX: Tanks installed in 2000s homes, often 2 per house, are at the end of their life.
- Elk Grove Village, IL: Homes from the 1970s are on their third or fourth tank.
- Spring Valley, NV: Scale shortens tank life, and many homes are on their second or third heater.
- Mount Pleasant, SC: Tanks installed around 2000 to 2010 are at the end of their life.
Other Water Heater Repair & Replacement Problems
Leaking Water Heater Questions
Is a leaking water heater dangerous?
Water damage is the main risk. But a discharging temperature and pressure relief valve can mean the unit is overheating, so shut it off and have it inspected.
Can a leaking tank be repaired?
No. Once the tank itself leaks, the inner lining has failed and the heater has to be replaced. Leaks from valves and fittings can usually be repaired.