Should You Turn Off a Water Heater If It's Leaking?
What this costs
| Option | Job | Low | High |
|---|---|---|---|
| Replace | Water Heater Replacement | $680 | $1,900 |
If you smell gas
Don't touch anything. The Public Service Commission of Wisconsin says to leave immediately and call your gas utility or 911 from a safe distance outdoors. Avoid lights, appliances, flames and cell phones near the leak.
Stopping the water
A. O. Smith's manual calls for a shut-off valve in the cold water line near the heater, so find yours now, before you need it. If it won't close or you can't find it, we recommend the main shutoff. Utah State Extension, in its 2016 frozen-pipe advice, says being able to shut off the main in a leak can greatly reduce damage.
Stopping the heat
We recommend not touching wiring or panels if water has reached them. Stay away and call an electrician.
- Electric: we recommend turning off the circuit breaker. A. O. Smith says to turn off power and water before repairing an element gasket leak.
- Gas: we don't give steps for gas controls. A. O. Smith treats a gas control valve leak as a professional job. If you smell gas, leave first and call from outside. Otherwise, your plumber can tell you what to do over the phone.
Is it the tank or a fitting?
A. O. Smith says loose fittings and a drain valve that isn't fully closed can cause leaks, and that most leaks come from faulty connections. A corroded tank usually needs replacing. A drip at the relief valve pipe often points to high pressure or thermal expansion. NC State Extension suggests inspecting the tank for drips or corrosion. Hot water can burn you, so be careful around any leak.
Water Heater Leaking? What to Do Right Now
Common questions
Is a leaking water heater an emergency?
Can I keep using it until the plumber comes?
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Last verified 2026-11-04
- A. O. Smith: Water heater not working guide — Loose fittings, drain valve, corroded tank usually needs replacing, turn off power and water before element repairs, call a pro for a leaking tank or gas leak.
- A. O. Smith: Water heater maintenance guide — Most leaks come from faulty water supply connections; relief valve drips point to pressure or thermal expansion.
- A. O. Smith: Residential electric water heater installation and use and care guide (April 2011) — Shut-off valve in the cold water inlet; know its location.
- Utah State University Extension: Advice to prevent frozen pipes (Jan. 4, 2016) — Knowing the main water shutoff; quick shutoff limits damage.
- Public Service Commission of Wisconsin: Natural gas consumer safety — If you smell gas, leave and call from a safe distance; avoid ignition sources.
- NC State Extension: Preventative home maintenance (Oct. 31, 2023) — Inspect tank for drips or corrosion.
General information, not professional advice. Conditions, codes and prices vary. Turn off power, gas or water before any work, and hire a licensed professional when in doubt. Cost figures are our estimates, not quotes.