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Water heater failure: emergency response and shutoff

A failing or burst water heater can dump tens of gallons of scalding or dirty water into your home in minutes. Shutting off power and water quickly limits flood damage.

Do this now

  1. Turn off power or gas to the water heater immediately.
  2. Shut off the cold water supply valve located on top of the water heater tank.
  3. If water is flooding your home, shut off the main water valve for the entire house.
  4. Attach a garden hose to the drain valve at the bottom of the tank and run it to a floor drain, sump pump, or outdoors to empty the tank.
  5. Call a licensed plumber for replacement or repair.

Step by step shutoff instructions

Step 1: Shut off power or gas first Heating element operation without water damages the unit or causes electrical hazards.

  • Electric water heater: Switch off the dedicated double-pole breaker on your main electrical panel.
  • Gas water heater: Turn the gas control valve dial on the front of the heater to OFF or PILOT.

Step 2: Shut off the water supply - Turn the lever or wheel valve on the cold water inlet pipe (located at the top of the tank) clockwise until tight. - If the valve is corroded or stuck, shut off the main house water valve.

Step 3: Relieve tank pressure - Open a hot water faucet on an upper floor to break the vacuum and let water drain faster.

Preventing catastrophic water heater leaks

  • Replace water heaters that are over 10 to 12 years old before tank corrosion causes sudden bottom seam rupture.
  • Install an automatic water shutoff valve with a floor sensor underneath the water heater catch pan.
  • Flush sediment out of the tank annually to extend heating element life.

... note "Home plumbing safety" Work on gas lines or electrical supply wiring beyond the shutoff switch must be performed by licensed plumbers or electricians.