Home / Water heater leaking
Symptom
Your water heater is leaking: what it means
The short answer
Where the water is coming from tells you almost everything. A leak at a valve, fitting, or connection can usually be repaired, and the heater can last years more. A leak from the tank body itself means the tank has rusted through and cannot be repaired, so it needs replacing. First, shut off the water supply to the heater and turn an electric unit off at the breaker or a gas unit to pilot, then find the source.
First, make it safe
- Turn off the water supply to the heater at the shutoff valve on the cold inlet.
- For an electric heater, switch it off at the breaker. For a gas heater, turn the control to pilot or off.
- Wipe the area dry and put down paper so you can see exactly where new water appears.
Find where it is leaking from
The connections at the top
Water at the top usually comes from the cold-inlet or hot-outlet connections. These are often tightened or resealed rather than replaced, one of the more affordable fixes.
The temperature and pressure relief valve
A leak or drip from the T&P relief valve, or from the pipe running down from it, can mean the valve is doing its job by releasing excess pressure, or that the valve itself has failed. Because this valve is a safety device, a persistent drip is worth having checked rather than capped. It can point to excess pressure or temperature that needs to be addressed, not just a bad valve.
The drain valve near the bottom
The drain valve at the base can weep if it is not fully closed or its seal has worn. It is usually an inexpensive part to replace.
The tank itself
Water pooling under the tank with no obvious source above it often means the tank has corroded from the inside out. A tank leak cannot be repaired, so this is the case that calls for replacement. See our water heater replacement cost guide for what that runs.
Repair or replace
If the leak is at a valve or fitting, repair is usually the right call. If it is the tank, or if the unit is already near the end of its life, replacement makes more sense. Our repair-versus-replace guide covers the rules of thumb plumbers use to decide.
Common questions
Leaking water heater questions
Can I still use water if the water heater is leaking?
You can still use cold water, since that comes straight from the supply. For a small, slow leak you can usually keep using the home briefly while you arrange a repair. For a steady leak, the safest move is to shut off the water to the heater and, for a gas unit, turn it to the pilot or off, then get it looked at.
How long will a water heater last once it starts leaking?
It depends entirely on where it is leaking from. A leak at a fitting, valve, or connection can often be repaired and the heater can last for years more. A leak from the tank itself means the tank has corroded through, which cannot be repaired, so a tank leak usually means replacement soon.
Is it safe to leave a leaking water heater on?
For anything more than a tiny drip, it is best not to. Water near electrical connections or a gas burner is a hazard, and a leak can worsen without warning. Turn off the water supply to the heater, switch an electric unit off at the breaker or a gas unit to pilot, and have it inspected.
What can happen if a water heater leak is ignored?
A slow leak can rot subfloor, feed mold, and damage anything stored nearby, and a failing tank can eventually let go and release its full contents at once. Because the water damage often costs far more than the heater, a leak is worth addressing quickly rather than watching.
Get a real number for your repair
Not sure if it is the tank or a fitting?
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