Water Heater Repair
Learn why a tank heater stays cold, drips, rumbles or loses its pilot flame.
Homeowner guide
Leaking Water Heater Base in Louisville, CO: What to Do
Water on the floor around a tank is stressful, but not every leak means the heater is finished. The first job is to stop the water. The second is to find out where it is coming from.
By the Flatirons Express Plumbing team ·
Shut things off first
For an electric heater, turn off the breaker. For a gas heater, turn the gas control to off or pilot. Then close the cold-water inlet valve above the tank. If the leak is heavy, open a hot tap somewhere in the house to relieve pressure.
Do not touch wet electrical parts. If the heater sits in a basement and water is spreading, protect belongings and call for help. A drain pan helps catch small leaks but will not stop a failing tank.
Check the top and the fittings
A lot of leaks that appear to come from the base actually begin higher up and run down the tank. Look at the cold and hot connections at the top, the relief valve and its discharge pipe, and the temperature and pressure fittings.
A loose union or a worn gasket can be fixed in minutes. Dry the tank, run a paper towel along each connection, and see which one gets wet.
The relief valve and thermal expansion
A temperature and pressure relief valve opens to protect the tank. A drip from its discharge pipe can mean the valve is worn, the pressure is too high or the water is overheating. In a closed system, expansion from heating can push pressure up.
An expansion tank on the cold line can absorb that expansion. If the valve drips repeatedly, ask a plumber to check pressure and the expansion tank.
Where the water is coming from
Not every puddle means a dead tank. Find the source before you decide.
| Source | What it suggests | What to do |
|---|---|---|
| Pipe fittings on top | A loose or worn connection | A plumber can tighten or replace the fitting |
| Relief valve or its discharge pipe | High pressure or temperature, or a worn valve | Do not cap it; have it checked |
| Drain valve near the base | A worn valve or a loose cap | Swapping the valve is usually a quick job |
| Seam or the tank base | Internal failure of the tank | Plan to replace the heater |
When the tank itself has failed
A tank that leaks from the seam at the bottom or through the jacket has corroded through. Steel tanks have a glass lining and an anode rod that protects them. When the rod is used up and the lining cracks, the tank rusts.
A failed tank cannot be repaired. It needs replacement. Look at the data plate for the age, and see water heater replacement for what the job involves.
Sediment and age
Sediment that builds on the tank bottom can overheat the steel, and crack or corrode it. Flushing the tank each year helps, and so does replacing the anode rod. A heater beyond ten years old deserves a closer watch.
Hard water scale accelerates the buildup. If your heater is noisy, it is telling you sediment is there.
Safety first
A leaking gas heater should be shut off at the gas control, and an electric one at the breaker, before you do anything else. Hot water can scald, and a tank that is leaking can carry electrical risk. Do not touch wet wiring.
Turn off the cold supply to the heater at its shutoff valve. Place a bucket under any drip and use towels or a wet vacuum on the floor. If the floor is carpeted or finished, lift items out of the way quickly.
Repair or replace
A leak at a fitting or valve is a small repair on a tank that is otherwise sound. A leak from the tank itself cannot be patched, and the heater has to be replaced. Age plays a part. A tank that has run for many years and leaks from the base is a poor candidate for a costly repair.
See water heater repair for what a technician checks, and water heater replacement for how sizing, venting and permits work when a new unit goes in.
Extending the life of the next heater
Flush a tank water heater once a year to clear sediment, and check the relief valve for signs of weeping. Keep the area around the tank clear. A drain pan with a line to a safe location catches small leaks before they spread across a floor.
Ask your installer about the anode rod and whether it can be checked. In hard water, scale builds up faster, so a softener helps. See softener installation and repair for options.
Condensation versus a leak
Moisture on a gas heater's base can be condensation, especially right after a new tank heats up with cold water. A small amount of water that disappears within a day and never returns is usually harmless.
Water that keeps coming back, grows or comes with rust streaks is a leak. Dry the area, place a sheet of paper or cardboard under the tank and check it the next morning. The dry or wet result tells you whether to call.
What to do next
Take photographs of the leak and the data plate for your records. If the heater is old and leaking, replacement is the answer. If a fitting is leaking, repair is quick. See water heater repair for what a plumber checks.
In Louisville, water heater replacement is permitted work that needs a plumbing license and a final inspection. Choose a contractor who pulls the permit.
Quick answers
Leaking water heater questions
A leak at a fitting or valve often can. A leak from the tank body cannot, and the tank needs replacing.
It can be. Water near electrical parts is a shock risk, and gas heaters need care. Shut off power or gas and the water supply.
Do not wait. Even a slow leak damages floors and can grow worse quickly.
The valve may be worn, the water pressure may be too high, or expansion may be building pressure.
Services that connect to this topic
Water Heater Installation & Replacement
Swap out a dead tank heater for one sized, fueled and vented to suit the home.
Water Damage Restoration
Dry and rebuild floors, drywall and basements after a leak, a frozen-pipe burst or a sump failure.
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Water heater leaking now?
Shut off the power or gas and the cold-water inlet, then call. The dispatcher explains the next step.