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Water Heaters · LeaksWater Heater Leak Repair
Water heater leak repair costs $150–$800 when the water is coming from a fitting, a valve or the relief line, and it is not possible at all when the steel tank has rusted through: that tank is replaced, typically for $1,200–$2,500 installed. The first job is finding out which of the two you have, because water from the top of a tank runs down inside the jacket and shows up at the bottom.
A tank water heater leaks from four places: the top connections (cold inlet and hot outlet nipples, flex connectors, the anode rod port), the T&P relief valve and its discharge pipe, the drain valve at the bottom, and the tank itself. Electric tanks add a fifth, the element gaskets behind the access panels. The technician dries everything, then traces the water upward from the puddle with a light and a mirror. A wet ring on top of the tank under a corroded nipple is a very different visit from rusty water weeping out of the jacket seam.
Everything threaded on is repairable. Nipples and connectors are replaced with dielectric fittings so the copper-to-steel joint does not corrode again, a plastic drain valve that will not reseal is swapped for brass, and a relief valve that drips is tested for over-pressure before it is changed. If the relief line runs every time the tank reheats, the cause is thermal expansion and the fix is an expansion tank, not a new water heater.
A leaking tank is not repairable. The steel shell is protected by a glass lining and an anode rod, and once the lining cracks and the steel rusts through at a seam, no weld, epoxy or sealant holds against pressure and heat cycling. The signs are rusty water at the base, rust tracks down the jacket, or water hissing in the burner chamber of a gas tank. Book a replacement tank before the weep becomes a split.
Not every puddle is a leak. A gas tank refilled with cold winter water condenses its own flue gases, and the drips sizzle on the burner and wet the floor until the tank warms up; a cold vent pipe or a sweating cold-water line in a humid summer basement does the same. Wipe everything dry and look again once the tank is fully hot. While you wait for a visit, turn the gas control to off (or switch off the breaker on an electric tank) and close the cold supply valve above the heater; how to turn off a leaking water heater has the steps in order.
Where the water shows up, and what it means
- A wet ring or white-green crust on top of the tank: a corroded nipple or connector, repairable
- Water at the end of the relief discharge pipe: a worn valve or over-pressure, repairable once the cause is measured
- A drip from the drain valve spout near the floor: a valve that did not reseal, repairable
- Rusty water from under the jacket or out of the burner compartment: the tank has failed, replace it
- Dampness only after a long shower or a laundry day, gone once the tank is hot: condensation, no repair needed
How it works
Close the cold supply valve above the tank and shut off the gas control or the breaker. Tell us whether the water is at the top, the side or the base and how old the tank is, and we will say whether it can wait until morning.
The technician dries the tank, lets it come back up to pressure and traces the leak to a part. A pressure gauge goes on the system if the relief valve is involved. You get the finding and the price in writing.
Fittings and valves are usually changed on the same visit from stock on the truck. If the tank has failed, the quote covers the new heater, removal of the old one and the gas, water and vent connections; request a visit.
Common questions
Is a leaking water heater dangerous?
A slow drip from a fitting is a nuisance, not a hazard, as long as water is not reaching the gas control, the burner or electrical parts. A leaking tank is different: the weep can become a split and release the whole tank plus whatever the open supply line keeps feeding it. Shut off the water and the fuel, and see why a water heater leaks for the full diagnosis.
Can a leaking tank be patched or sealed?
No. The leak is the visible end of corrosion that has already gone through the lining, and the tank sees full house pressure and a heating cycle many times a day. Sealants and patch kits fail without warning, usually when nobody is home. Anyone offering to weld or seal a residential tank is selling you a flood.
Does home insurance cover the damage?
That depends on your policy, and usually on whether the escape of water was sudden or gradual. Take photos, note the date you found it and call your insurer before the old tank is hauled away. We write the cause and the tank's age on the invoice so you have documentation; does home insurance cover a leaking water heater explains the usual distinctions.
My tank is a rental. Who do I call?
The rental company. A rented tank belongs to them, and leak repair or replacement is their responsibility under the rental agreement, so calling an outside contractor first can leave you with a bill they would have covered. If you are tired of the monthly fee, $25–$45 a month in most contracts, ask us about buying your own tank once the leak is dealt with.
How long can I leave a slow drip from the drain valve?
A few days with a bucket under it, if the drip is from the spout and not from the threads where the valve meets the tank. A hose cap with a rubber washer on the spout stops most of them until the visit. Rust or moisture around the valve threads means the tank wall is involved, and that should be looked at this week.