Water Heater Leaking From the Bottom? What to Do Now

Likely causes (not a remote diagnosis)

Water at the base of a heater usually traces back to one of a handful of sources. Which one it is has to be confirmed in person, because the water almost always travels before you see it.

• Drain valve at the bottom. The plastic or brass valve near the floor can weep after being used or bumped.
• Temperature and pressure relief discharge. If the relief line terminates near the floor, water there may be the heater shedding pressure rather than a tank failure.
• Connections above the tank. A dripping flex line, union or expansion tank fitting runs down the outside of the shell and collects at the base, which looks identical to a bottom leak.
• Internal tank corrosion. After years of hard-water sediment sitting on the bottom, the tank liner can perforate. This is typically a replacement, not a repair.
• Condensation, especially in Brevard garages. On humid days a cold tank surface sweats and drips. It looks alarming and usually stops as the tank warms.

Safe observations you can make

• Photograph the puddle and the whole heater from a few feet back.
• Dry the floor, then watch for 15–30 minutes to see whether water returns and where the first drop lands.
• Look for rust streaks, a stained drip pan, or a wet line running down one side of the shell.
• Note whether hot water still works and whether the water looks rusty at a tap.
• Find the rating label and write down the brand, model, capacity and manufacture date.
• Check the pan drain, if there is one, for a clog holding water in place.

What not to do

• Do not remove access panels, thermostat covers, or any electrical cover on the heater.
• Do not take apart, adjust, or "test" a gas control valve or burner assembly.
• Do not lift or manually open the temperature and pressure relief valve to see what happens.
• Do not tighten fittings on a hot, pressurized tank.
• Do not stand in water while touching the heater, its wiring, or a breaker panel.
• Do not patch, epoxy, or clamp a rusted tank. A tank that has failed cannot be sealed safely.

When professional help is warranted

Bring in a plumber when the leak returns after drying, when you cannot tell which component the water is coming from, when the shutoff valve is seized, when the heater is gas-fired, when the tank is more than roughly eight to twelve years old, or when the heater sits above living space or near finished flooring. Same-day attention is reasonable for an active leak; see our emergency plumbing page if it cannot wait.

Have this ready before you call

• Photos: the puddle, the full heater, the rating label, and any wet spot on the wall or ceiling.
• Brand, model number and capacity from the label.
• When you first noticed water, and whether it is getting worse.
• Whether you were able to close the cold-water valve and cut power or gas.
• Fuel type: electric, gas, tankless, or hybrid/heat pump.
• Where the heater is: garage, closet, attic, or utility room.
• Whether the home is on municipal water or a well, and whether you have a softener.
• Your address and the best number to reach you.

Related help on this site

• Water heater repair and replacement
• Leak detection — useful when water appears but the source is hidden.
• Pipe repair for leaks at supply lines rather than the tank.
• Low water pressure in your house