How to flush
your water heater.

How do I flush a water heater?

You need a garden hose long enough to reach a floor drain or outside, a flathead screwdriver or pliers to open the drain valve, and ideally a bucket to confirm the water runs clear. Turn the gas dial to PILOT (or switch off the breaker on an electric heater), let the water cool if you can, shut the cold water supply at the top of the tank, connect the hose to the drain valve at the bottom, open a hot water faucet inside, and open the drain valve. The water comes out hot enough to scald, so run the hose where no one can touch it. Refill the tank completely before turning the gas or breaker back on.

What tools do I need to flush a water heater?

• Garden hose (long enough to reach a drain or outside)
• Bucket (to check that the water runs clear)
• Flathead screwdriver or pliers (for the drain valve)

Before you start: If your heater is over 10 years old and has never been flushed, the drain valve may be partly clogged with sediment. Flushing can stir up debris that doesn't fully drain out, and in rare cases an old valve won't close tightly again. If you'd rather not take that risk, call or text Sweetwater and we'll flush it for you.

How do I flush a water heater step by step?

1. Turn off the heat: Gas: turn the gas control to PILOT or VACATION. Electric: switch off the water heater's breaker. Never let an electric heater turn on with an empty tank; it burns out the elements.
2. Let the water cool: Tank water is 120°F or hotter and can scald. If you can, give it time to cool after turning off the heat.
3. Shut off the cold water: Close the cold water supply valve on the pipe at the top of the tank.
4. Connect the hose: Attach the garden hose to the drain valve at the bottom of the tank and run the other end to a floor drain or a spot in the yard where it can soak in (not the street or gutter), away from people, pets, and plants.
5. Drain the tank: Open a hot water faucet inside the house so air can get in, then open the drain valve and let the tank empty.
6. Flush the sediment: With the drain still open, turn the cold supply on in short bursts to stir up sediment. Repeat until the water runs clear into a bucket.
7. Close the drain valve: Turn it fully closed, remove the hose, and make sure the valve isn't dripping.
8. Refill before restarting: Turn the cold supply back on and leave the hot faucet open until water flows steadily with no sputtering, then close it. Only then turn the gas control back to ON (relight if needed) or switch the breaker back on.

When to stop and call Sweetwater: If you smell gas, leave the house first and call SoCalGas at 1-800-427-2200 and 911 from outside. If the drain valve won't open, leaks after you close it, or the water never runs clear, stop and call (909) 312-4516 or text (909) 247-6791.

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