Home / Learn / Water Heaters / Why Is My Water Heater Leaking From the Bottom?
Why Is My Water Heater Leaking From the Bottom?
A water heater leaking from the bottom almost always means the internal tank has corroded through — and a corroded tank cannot be patched, only replaced. The exception: if the drip traces to the drain valve or a fitting rather than the tank body itself, a simple repair may solve it.
Categories
The two possible sources — and why the difference matters
Every bottom leak comes from one of two places. The first is the drain valve, the spigot-style fitting near the floor of the tank. Valves loosen, wear, or catch debris, and replacing one is a quick, inexpensive repair. The second source is the tank body itself. Steel tanks are protected on the inside by a glass lining and a sacrificial anode rod; once the rod is consumed, corrosion goes to work on the steel, and eventually water finds its way through. When the tank wall itself is weeping, no repair will hold — the leak will only widen.
How to tell which one you have
Dry the area completely, then watch. Water beading at the drain valve or dripping from its outlet points to the valve. Moisture appearing along the tank's bottom seam, or rust streaks running down from under the outer jacket, points to the tank. A second clue is age: check the manufacturer's label near the base — the serial number's first digits usually encode the production year. A leaking unit past ten years old is overwhelmingly likely to be tank failure.
What to do right now
Shut off the cold water supply valve above the heater, then cut the power — the gas valve on a gas unit, the breaker on an electric one. This stops the leak from feeding and protects the heating elements or burner. If water is spreading toward finished flooring or stored belongings, move what you can. A leaking tank rarely bursts without warning, but a slow bottom leak is the warning.
What repair or replacement costs in Central Indiana
A drain valve replacement is a modest service call. Full tank replacement — professionally installed with permit, expansion tank, pan, haul-away, and code compliance — typically runs $2,000 to $4,500 in the Anderson, Fishers, and Indianapolis area, depending on capacity and fuel type. Homes replacing an aging tank often compare tankless at this decision point; a turn-key tankless installation runs $4,500 to $7,000.
When to call a professional
Immediately, if the leak is from the tank body — every day of delay is a gamble against a much larger water cleanup. Same week, if it's the drain valve. Either way, a licensed plumber can confirm the source in minutes and give you both numbers on the spot.
Leaking water heater in Anderson, Fishers, or Indianapolis? Home Heroes diagnoses the source and gives you honest repair-versus-replace numbers in one visit. Call now or Book Online — same-day service available.
Reviewed by Vince Hileman, Licensed Plumber - IN License #PC11500076
Published Date: August 31, 2026 | Last Updated Date: August 31, 2026
