How to Drain a Water Heater

If you're learning about the proper maintenance of your water heater, then you need to know how to drain a water heater. For this project, you're going to need a garden hose, and if the hose can't reach outside, then fill a bucket and dump, and repeat.

Why Should I Drain It in the First Place?

From time to time, your tank water heater needs to be flushed because naturally-occurring minerals settle in the bottom. If you let it go for too long, it can eventually plug your drain, and you don't want that because how then will you clean it out? The consequence of having too much of these solids in your tank can reduce efficiency. You may even hear the sediment making popping noises when the water heater heats up.

How Often to Drain Water Heater?

Depending on the area where you live, you should flush your water heater every 1-2 years.

How to Flush a Hot Water Heater

The steps are slightly different if you have an electric versus a gas-fueled water heater. We'll cover gas water heaters first, then tackle electric tanks.

How to Drain a Gas Water Heater

Shut off the water supply - close the cold water supply valve.
Turn the thermostat to pilot - if you turn it off, you'll have to relight the pilot when you're all done. Setting it to pilot mode saves you the trouble.
Wait hours for the water to cool off - you can't drain the tank right away because the water is too hot. Do steps 1 and 2 at night, and then sleep on it before moving on to step 4.
Attach a hose to the drain valve - you can use a garden hose. Connect it to the drain valve near the bottom of the tank. Run the hose outside the house.
Open a hot water valve inside the home - run to the kitchen or a bathroom and turn on a faucet for hot water. You will not get hot water; it's for alleviating pressure in the line.
Open the drain valve - leave it open until the water stops coming out.

Once you're done, close the drain valve, open the water supply valve. Remember the faucet you turned on inside, when cold water starts coming out of there, shut off that faucet. It's now safe to turn the thermostat back to its normal setting and allow it about 30-60 minutes to heat up.

How to Drain an Electric Water Heater

Shut off the water supply - close the cold water supply valve.
Cut the power supply at the breaker is very important because water heater elements will quickly burn out if they are not submerged in water.
Wait hours for the water to cool off - you can't drain the tank right away because the water is too hot. Do steps 1 and 2 at night, and then sleep on it before moving on to step 4. If you are draining it to replace a heating element and the water is already at room temperature, there is no waiting period.
Attach a hose to the drain valve - you can use a garden hose. Connect it to the drain valve near the bottom of the tank. Run the hose outside the house.
Open a hot water valve inside the home - run to the kitchen or a bathroom and turn on a faucet for hot water. You will not get hot water; it's for alleviating pressure in the line.
Open the drain valve - leave it open until the water stops coming out.

Once you're done, close the drain valve, open the water supply valve, and let it fill until the faucet you left on inside starts delivering cold water. It's now safe to turn the electricity back on to your water heater. Wait about 60-90 minutes for your water heater to heat back up.

If you prefer another learning method, try watching this Rheem youtube video about how to flush a water heater.

How Long Does It Take to Drain a Water Heater?

The waiting is the hardest part. Draining a hot water heater doesn't require much labor, but the process does require time. We recommend letting the tank cool off overnight. It only takes about 5 minutes for the tank to drain. So you're probably looking at about 15 minutes of work over 8 hours.

Lean on the PlumbersStock Experts

Whether you need replacement water heater parts or some questions answered, you're in the right place. We have lots of helpful water heater resources. Not only do we have the best prices, but we also carry brands you trust. For example, if you are in the market for a new on-demand water heater, why not try one of our Bradford White solutions? If you have project questions that are not answered here on our site, please contact us!