Every once in awhile we get into a situation where a water heater won’t drain. There are a few tips that can be used in order to get the heater to drain down.
A water heater should be drained down at least once per year. Draining the tank will help remove some of the sediment that naturally builds up in your water heater. By draining your water heater you can increase the lifespan of the tank.
If you are trying to drain your water heater but it doesn’t seem to want to drain down that best trick is to pull the t&p valve that is located either on top or the side of the water heater. Make sure that you have turned the valve feeding into the water heater off to prevent the water from filling back up. The T&P valve should let air into the tank which will allow the water to drain down. You can also try opening a faucet on the hot water side.
Another problem that we have ran into with particularly old water heaters is the drain valve not releasing all the way.