Quick Answer
First, determine where the water actually starts. Water found at the bottom of a heater may come from the tank body, drain valve, T&P discharge path, or a connection above that is running down the jacket. A confirmed tank-body leak requires replacement; a valve or connection leak may be repairable.
Common Symptoms
- •Water pooling under the heater
- •Drip from the T&P relief valve
- •Rust streaks down the side of the tank
Possible Causes
- •Corroded tank body or seam — confirmed pressure-vessel leaks are not repairable
- •Leaking or discharging T&P relief valve
- •Leaking drain valve
- •Leaking inlet/outlet connection above the tank
Safe Things You Can Check
If you can operate the cold-water supply valve safely, shut off water to the heater. For an electric unit, use the dedicated breaker; for a gas unit, use only the manufacturer's normal shutdown controls.
Dry visible surfaces if safe and watch where water first appears; water can travel down the jacket, so the lowest wet point is not always the source.
Do not cap a T&P discharge, open electrical compartments, or disturb gas piping as a homeowner leak check.
WHEN TO CALL
Any leak from the tank body means replacement. A leaking valve can be replaced, but act quickly — a small leak becomes a flood.