Shut it down safely first
Water from a water heater can be scalding. Work slowly and keep children and pets away.
- Close the cold supply.The cold-water inlet valve is on the pipe that enters the top of the tank. Turn it clockwise, or turn the lever across the pipe if it is a ball valve.
- Turn off the heat source.Set a gas control to Off, or switch off the double breaker for an electric unit. Never run an electric heater that may be empty.
- Contain the water.Use towels or a wet-dry vacuum and move stored items away. A drain pan under the tank helps if one is installed.
- If the leak is heavy or you cannot close the inlet.Close the main water shutoff to the house instead.
Where is the water coming from?
| Leak location | What it usually means | Typical next step |
|---|---|---|
| Pipe connections on top | Loose or corroded fitting, worn flex connector, or failing dielectric union | Fitting or connector repair |
| Relief valve or its discharge pipe | High pressure, thermal expansion, overheating or a worn valve | Diagnose pressure before replacing the valve |
| Drain valve near the bottom | Valve not fully closed or a worn plastic drain valve | Cap or replace the drain valve |
| Under the tank with dry fittings | Corrosion through the inner tank | Plan for replacement |
| Condensation on a cold morning | Moisture from combustion on a gas unit, often temporary | Watch it; call if it continues once the tank is hot |
Why tanks fail from the inside
A steel tank is protected by a glass lining and a sacrificial anode rod that corrodes so the tank does not. Fullerton's hard water, a blend of local groundwater and imported water, adds mineral sediment that settles on the bottom and can speed up wear. Once the anode is used up, rust begins working on the tank itself.
When water seeps from the tank body, there is no lasting patch. Fittings, valves and connectors are replaceable parts; the tank is not. That is why the location of the leak matters more than its size.
What to do next
- IfThe leak is at a top fitting and the tank is dryThenLeave the heater off and have the fitting or connector repaired. This is often a modest job.
- IfThe relief valve is dripping or dischargingThenDo not cap or plug it. Have the water pressure and expansion control checked before the valve is replaced.
- IfWater is seeping from the tank bodyThenKeep the heater off, get written quotes for replacement, and confirm they include strapping and venting.
- IfYou cannot tell where it startsThenLeave it off and let a licensed plumber trace it before any parts are bought.
Questions for the plumber
- Where exactly is the water coming from, and how did you confirm it?
- If it is a fitting, is the rest of the tank in reasonable shape?
- If replacement is needed, does the quote include a drain pan, seismic strapping and relief valve discharge piping?
- Will a permit be pulled for the replacement? Check with the city if you are unsure.
- Who removes and disposes of the old tank?
Common questions
Can I keep using a leaking water heater for a few days?
If the leak is a slow drip from a fitting and the area stays safe, some people wait for an appointment with the heater off. A leak from the tank body can worsen without warning, so keep the supply closed until it is replaced.
Is a puddle always a leak?
Not always. Gas water heaters can produce condensation when filling with cold water. If the water stops once the tank is fully heated, condensation is the likely cause.
Does a leaking water heater need a permit to replace?
Water heater replacement involves gas or electrical connections, venting and safety devices, so a permit may apply. Check with the City of Fullerton's building department and ask your contractor who will pull it.
General information for Golden Hills, not a quote or professional advice. In an emergency, call 911.