Replacing a hot water heater drain valve is not as bad a job as you might think. You can do it without draining your water heater if your drain valve is clogged.
If your trying to drain a water heater and the drain valve has clogged, the best answer is to install a ball valve. Its just as easy and only cost a few dollars more.
Learn how to install a ball valve on the flush hot water heater page.
This guide is for replacing a drain valve with a full tank
of water.If you
prefer to drain your tank first and your not sure how to do it, follow the
link below for instructions.
Water heater drain valves are made
of plastic or brass. The valve on the
far left is gray plastic.
Brass valves will last much longer
and give you less trouble.
For electric water heater turn
the power off.
Gas water heater turn the control
valve to pilot.
Run the hot water in a sink or tub until the water runs cold.
Turn off the water supply valve on your water heater.
Don't turn on any faucets in your house and make sure no one else does or you'll get really wet.
The idea is to create a vacuum in your water heater tank so the water
can't come out or I should say,so it will come out slowly.
Be sure the water supply valve is turned off as tight as you can get it
with your hand.
Prepare your new drain valve
to be installed.
You can use teflon tape or
Place a small bucket under the old
drain valve and open the valve and
let the water run for two or three
This will relieve the pressure off
the tank so it won't spray you when the drain valve is removed.
Ok, time to remove the old water heater drain valve. Use an adjustable wrench or slip joint pliers and loosen the valve. Now get a firm grip on the drain valve and slowly unscrew it.
If the water supply valve is made of pvc it may not turn off completely and you could have some pressure in the tank by the time you take the drain valve out so be prepared.
It will just be a quick spray but will surprise you if you don't know
Screw the new valve in as soon as
you remove the old one.
You should not lose more than a
couple of cups of water.
I left the collar off this drain valve
so you could see how it is installed.
The valve was out of this tank for
30 to 40 seconds while I took
It takes less than 10 seconds to
thread a new one in after the old
valve is removed.
It filled a gallon container half full
of water before I installed the new
If you have a plastic drain valve I recommend that you replace it with
a brass one.
The plastic valves are easy to cross thread when trying to attach a drain hose, also they are more likely to leak.
A standard water heater drain valve for a residential hot water heater is 3/4 in. thread size.