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How to fix a water heater leak

We'll locate the leak, fix the drain valve or connections, and tell you when to call a plumber—especially if the tank is leaking.

How-to · Home plumbing
30–90 min
What you'll need
  • Replacement drain valve (if needed)
  • Replacement pressure relief valve (if needed)
  • Wrench, bucket, garden hose (for draining)

At a glance

  • Shut off the power (electric) or gas (gas unit) and the water supply before working on the water heater.
  • Locate the leak—drain valve, inlet/outlet connections, pressure relief valve, or tank.
  • Tighten the drain valve or replace it if it is dripping.
  • Tighten the inlet and outlet connections if the leak is there.
  • Call a plumber immediately if the tank itself is leaking—the tank cannot be repaired.
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Steps

Goal: Shut off power and water, locate the leak, fix the drain valve or connections, and know when to call a plumber.

  • For electric: turn off the circuit breaker. For gas: turn the gas valve to pilot or off. Shut off the cold water supply valve above the water heater.
  • Good: No power or gas and no water flow. Proceed to Locate the leak.
  • Bad: Power, gas, or water still on—find the correct shutoffs.

Locate the leak

Goal: Identify where the water is escaping.

  • Dry the area around the water heater. Turn the water supply back on briefly and watch where water appears—at the drain valve, at the inlet or outlet connections, at the pressure relief valve, or at the tank itself.
  • Good: You see water at the drain valve, connections, or pressure relief valve. If the tank itself is wet or rusty, call a plumber immediately—do not proceed.
  • Bad: Tank is leaking—call a plumber. The tank cannot be repaired.

Fix drain valve

Goal: Stop leaks at the drain valve.

  • Try tightening the drain valve with a wrench—do not overtighten. If it still drips, the valve seal is worn.
  • Shut off the water and drain the tank partially. Replace the drain valve with a new one of the same size and type. Refill the tank and turn the power or gas back on.
  • Good: No drips at the drain valve when the water is on.
  • Bad: Still leaks—call a plumber.

Tighten connections

Goal: Stop leaks at the inlet or outlet connections.

  • Shut off the water. Check that the pipes are fully threaded and the nuts are snug. Tighten the nuts a quarter turn—do not overtighten.
  • Turn the water on and check for leaks.
  • Good: No drips at the connections.
  • Bad: Connections will not seal—call a plumber.

When to get help

Call a plumber immediately if:

  • The tank itself is leaking (water on tank surface, rust, wet spots). The tank cannot be repaired.
  • The leak is at the gas line.
  • You have a gas water heater and are not comfortable.
  • The leak persists after tightening.

Do not delay if the tank is leaking—water can cause significant damage.

Verification

  • No drips at the drain valve, inlet, outlet, or pressure relief valve when the water is on.
  • The tank surface is dry with no rust or wet spots.

Reviewed by Blackbox Atlas

Frequently asked questions

Why does my water heater leak?
Common causes: a loose or worn drain valve, loose inlet/outlet connections, a faulty pressure relief valve, or a corroded tank. The drain valve is at the bottom; a loose valve or worn seal causes drips. A leaking tank means the unit must be replaced.
Can I fix a water heater leak myself?
Yes, for leaks at the drain valve or inlet/outlet connections. Shut off power and water first. If the tank itself is leaking, do not attempt repair—replace the unit. Gas water heaters require extra care; call a plumber if you are unsure.
When should I call a plumber for a water heater leak?
Call a plumber immediately if the tank itself is leaking, the leak is at the gas line, or you have a gas water heater and are not comfortable. A leaking tank cannot be repaired—the unit must be replaced. Do not delay—water can cause significant damage.

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