Troubleshooting
Water Heater Leaking: Causes, Fixes and Repair Cost
Leaks from fittings, the drain valve or the temperature and pressure valve are repairable. Water seeping from the bottom of the tank body means internal corrosion, and that tank must be replaced.
Verified August 2026
Typical repair cost
$0–$2,600
Most likely cause
Loose or corroded inlet/outlet fitting
DIY-checkable steps
4
Why is my water heater leaking?
Loose or corroded inlet/outlet fitting
Leaks from fittings, the drain valve or the temperature and pressure valve are repairable. Water seeping from the bottom of the tank body means internal corrosion, and that tank must be replaced.
Safety first: Shut off the cold-water supply and the power or gas before working near a leaking heater. Water plus electricity is a shock hazard.
Likely causes and what each costs to fix
| Cause | Likelihood | Fix | Cost |
|---|---|---|---|
| Loose or corroded inlet/outlet fitting | Most common | Re-seal or replace the fitting. | $100–$300 |
| Failed drain valve | Common | Replace the drain valve. | $120–$300 |
| T&P relief valve discharging | Common | Diagnose excess pressure; add or repair the expansion tank. | $150–$500 |
| Corroded tank body | Common | Full water heater replacement. | $1100–$2600 |
| Condensation on a gas unit | Less common | None needed if it stops once the tank reaches temperature. | No cost |
What you can check yourself
- 1. Dry the area and identify exactly where water reappears
- 2. Check whether the drip is at a fitting or from underneath
- 3. Confirm the T&P discharge pipe is not the source
- 4. Note the manufacture date on the data plate
When to call a professional
- • Water is coming from the tank bottom
- • The T&P valve discharges repeatedly
- • There is any gas smell
- • The unit is over 10 years old