Water Heater Is Leaking
First, identify where the water actually starts. Water seen at the bottom of a heater can come from the tank body, drain valve, relief-valve discharge, or a fitting above that runs down the jacket. A confirmed leak through the steel tank body is not repairable and requires replacement; valve or connection leaks may be repairable. If the source is unclear, shut the unit down safely and have it diagnosed before assuming the tank itself failed.
- —Corroded tank body — a confirmed tank-body leak is not repairable and requires replacement
- —Leaking T&P (temperature & pressure) relief valve
- —Leaking drain valve at the bottom of the tank
- —Loose or corroded inlet/outlet fitting on top
Try This First
Safe, simple steps you can try yourself. If any step feels beyond your comfort level, skip it and continue below.
- 1
Shut down the heater safely
Shut off the cold-water supply to the heater if you can operate the valve safely. For electric units, use the dedicated breaker. For gas units, use only the normal user controls or manufacturer shutdown procedure; if you smell gas, leave the area and call the gas utility from a safe location.
- 2
Identify the source without opening electrical compartments
Dry visible surfaces if safe and look for where water first appears: the tank jacket or seam, drain valve, T&P discharge path, or a top water connection. Water can travel down the outside of the heater, so the lowest wet point is not always the source.
- 3
Place a bucket or towel
If the leak is small and from a valve, contain it with a bucket. If it's from the tank body, the tank has failed — do not delay replacement.
If the problem is resolved
If the source is a simple external connection and it is properly repaired, dry the area and monitor for recurrence. Do not disturb gas piping, relief-valve components, or energized electrical parts as a homeowner check.
If the problem persists
If the tank body or a tank seam is confirmed as the source, the pressure vessel itself cannot be patched as a normal repair and the heater needs replacement. If the source is still uncertain, professional diagnosis is appropriate before replacing the unit. Continue below.
Stop and Call a Plumber If…
- Water is confirmed to be coming through the tank body or tank seam — the pressure vessel has failed and replacement is required
- The leak is large and growing — a small tank leak becomes a flood
- You see rust streaks down the side of the tank
- The T&P valve won't stop running — this can indicate dangerous pressure buildup
- You smell gas near a gas water heater
- ✓Confirming the leak source — tank body vs. valve vs. fitting
- ✓Testing the T&P relief valve for proper operation
- ✓Checking the drain valve for corrosion
- ✓Evaluating the tank age and condition for replacement
- ✓Verifying proper gas supply and venting (gas)
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Reviewed by Paul Hall, Owner & Licensed Plumber
The Classic Plumber · Knoxville, TN · License #4268. This guidance is general — an onsite inspection may be required for a confirmed diagnosis.