Common Sources of a Water Heater Leak
A leaking water heater generally traces back to one of four sources: the temperature and pressure relief valve, a fitting or connection point, the drain valve at the base of the tank, or the tank itself. Each of these has a different likely cause and a different fix.
Valve and fitting leaks are often the least serious, frequently fixable without replacing the entire unit. A leak from the tank body itself is the most serious, since it typically means internal corrosion has worn through the metal.
When a Water Heater Leak Is a Simple Fix
If the leak is coming from a specific valve or fitting rather than the tank body, it is often a straightforward repair: tightening or replacing the affected part. This is more common in newer water heaters where the tank itself is still sound but a component has loosened or worn out.
A plumber can typically diagnose this quickly by identifying exactly where the water is originating.
When a Leak Means Full Replacement
If water is coming from the tank itself, not a specific valve or fitting, this almost always means internal corrosion has worn through the metal, and there is no reliable repair for this. Water heater tanks are not designed to be patched once the metal has failed; the unit needs to be replaced.
This is more common in water heaters approaching or past their typical 8 to 12 year service life, which is why age is such a useful clue when diagnosing a leak.
What to Do Right Now If Your Water Heater Is Leaking
Shut off the water supply valve to the unit if you can reach it safely, and shut off the gas or electrical supply to the water heater as well, following your specific unit's shutoff procedure. This stops the situation from getting worse while you arrange for an assessment.
If the leak has already reached your flooring, cabinetry, or nearby walls, that water damage needs separate extraction and drying attention regardless of what happens with the water heater itself.