Do these now
- Turn off the energy. Electric: switch off the water heater breaker. Gas: turn the control knob to "off" or "pilot".
- Close the cold-water supply valve on the pipe going into the top of the tank.
- Protect the area. Move belongings, and use towels or a wet vac. If water is spreading toward outlets, keep clear.
- If the tank is leaking badly, attach a hose to the drain valve at the bottom and drain it to a floor drain or outside. Hot water can scald, so let it cool first if you can.
Leaking water heater? Call a local plumber
Where is it leaking from?
| Where you see water | Likely cause | Usually |
|---|---|---|
| Pipes or fittings on top | Loose connection, worn flex connector, corroded nipple | Repair |
| Relief (T&P) valve or its discharge pipe | Too much pressure or heat, a failed valve, or a missing/waterlogged expansion tank | Repair; have the cause checked |
| Drain valve near the bottom | Valve not fully closed or worn out | Repair (valve replacement) |
| Under the tank, from the bottom seam | Tank corroded through | Replace the tank |
| Rust streaks or weeping on the tank body | Internal corrosion | Replace the tank |
| Drips inside the burner area of a gas tank | Condensation on a cold tank, or a leak above | Watch it; condensation fades once the tank is warm |
Relief valve dripping?
The temperature and pressure relief valve opens when the tank gets too hot or too much pressure builds. Don't cap or plug it. Common causes are a thermostat set too high, a failed valve, or high pressure in a home with a pressure-reducing valve and no working expansion tank. That last one is common in Upstate homes built in the 2000s and 2010s. Our repair-or-replace table covers the other symptoms.
Leaks in a closet, attic or upstairs
A tank in a garage leaks onto concrete. A tank in a hall closet, attic or upstairs laundry room leaks into floors and ceilings. If yours is in one of those places, check that it sits in a drain pan piped to a drain or outside, and consider a leak alarm (a small battery sensor) under it. Insurers see water heater failures as one of the common causes of indoor water damage.
If the tank has to be replaced
A leaking tank can't be patched. A standard 40–50 gallon tank, installed, runs about $1,300–$2,200 on local figures. Some cities, including Mauldin, require a permit for the replacement. Our replacement guide covers sizing, permits and what happens on install day. If you're thinking about switching, see the tankless guide.
Insurance and cleanup
- Photograph the leak and any damage before cleanup.
- Homeowner's policies often cover sudden water damage to floors and walls, but usually not the worn-out tank itself.
- Dry the area quickly with fans and a dehumidifier; damp drywall and subfloor can grow mold within a day or two in warm weather.
Need it fixed or replaced? Call a local plumber
Water heater leak questions
Is a leaking water heater dangerous?
The water itself is mostly a damage risk, but water near electrical parts or a gas burner can be a hazard. Turn off the power or gas and close the cold-water valve, then call a plumber.
Can a water heater leaking from the bottom be repaired?
If the water comes from the drain valve, yes. If it comes from the tank's bottom seam or through rust, no; the tank has to be replaced.
Should I turn off the water heater if it's leaking?
Yes. Switch off the breaker on an electric tank or set a gas tank to off, and close the cold-water supply valve. Running an electric tank without water can burn out the elements.
Why is water coming out of the relief valve pipe?
The valve is releasing heat or pressure, or it has failed. A missing or waterlogged expansion tank is a common cause in newer homes. Don't plug it; have it checked.
How long can I use a leaking water heater?
Not safely for long. A small fitting leak may hold for a day, but a tank leak only gets worse and can fail suddenly. Shut it down and schedule the repair or replacement.
Why is my new water heater dripping?
Often condensation while a cold tank first heats up, which stops once it's warm. If it keeps dripping, a connection may be loose, so call the installer.
Sources
- Resident.com (Greenville, SC, Mar 2026) and This Old House (Greenville, SC) water heater installation costs.
- City of Mauldin water heater permit requirement.
- General manufacturer guidance on relief valves, drain valves and condensation.
Page history
October 2026: first published.