Plumbing · Common problems · Updated November 2026
Leaking Water Heater: What to Do Right Now
A small drip from a fitting can often be repaired. Water coming from the tank itself usually means the tank has corroded through, and the heater needs to be replaced.
If you smell gas, leave the house and call 911 or your gas utility from outside. Otherwise: turn off the cold water supply valve to the heater, then turn off its power (electric: switch off the breaker; gas: turn the control to "off" or "pilot"). Water in the tank can be scalding hot.
Find where the water is coming from
| Leak location | What it usually means |
|---|---|
| Pipe connections at the top | Loose fitting or worn supply line; often repairable |
| Temperature and pressure (T&P) relief valve or its discharge pipe | Valve is releasing pressure or failing; needs a pro to check why |
| Drain valve near the bottom | Valve not fully closed or worn; often repairable |
| Bottom of the tank or a puddle with no other source | Tank failure; replacement needed |
| Condensation on a new heater in cold weather | Can be normal at first; should stop |
What you can safely do
- Shut off the water and power or gas as described above.
- Move belongings away from the water and dry the area.
- Note the age of the heater; the manufacture date is often coded in the serial number on the label.
- Do not attempt to repair or remove the T&P valve yourself.
When to call a pro
Call a plumber for any leak from the tank or the T&P valve, or if you cannot find the source. A like-for-like tank replacement typically costs $600–$2,500; switching to tankless runs $1,400–$3,900 (plumbing cost guide).
Cost figures are national ranges from the sources listed in our plumbing cost guide, not a quote from FixFinch or any contractor. This article is general information to help you decide on next steps. It is not an inspection or professional advice; a qualified pro who sees the problem in person can tell you what is actually going on. Calls connect you with an independent service provider in our network. FixFinch is not a contractor and does not perform the work.