Note: Leaking natural gas can be dangerous. If you smell natural gas (it smells kind of like garlic) near the water heater, shut off the pilot light, close the gas shutoff valve, and call a plumber or your gas utility for assistance. See our information on gas leaks.
How to Flush and Drain a Water Heater
Before draining and flushing your water heater, turn off the gas or electric power (depending upon whether it is a gas or electric water heater) and let the water cool a little if you can. Close the incoming water valve and attach a hose to the drain valve to run the water into a large bucket or to a drain or the outdoors. Open the drain valve and open one hot water faucet somewhere in the house or apartment to let in air. When all water has drained from the water heater, turn the cold water valve on and off until the water from the drain runs clear. Then close the drain valve and the hot water faucet, open the cold water valve, and turn the water back on.
This is also a good time to test the temperature-pressure relief valve, which keeps pressure from building up too much in the boiler. Lift or lower its handle. Water should drain from the overflow pipe.
Water heater tips
- Set the temperature control to about 150 degrees Fahrenheit or lower if you have no dishwasher or if you have small children or elderly people in the home who might scald themselves.
- To maximize your water-heating energy, insulate your water pipes if they run a long way from your heater to your faucets. Also consider installing a point-of-use water heater.
- Always shut off the power to an electric water heater before working on it.
- Do not work on an electric water heater if there is standing water pooled on the floor near the appliance. Shut off the circuit to the water heater and call a qualified water heater repairperson.
Water heater problems normally become self-evident: A hot water faucet fails to summon hot water, you see puddles or a leak near the water heater, or the tank emits strange gurgling or popping sounds.