Replace the drain valve:
- For this repair the water heater must be empty of water. The first thing to do is to drain the water heater completely.
- When the water heater is completely drained remove the leaky drain valve by unscrewing the it in the counter-clockwise direction with pliers or a small pipe wrench.
- Get your replacement valve. You will not know exactly how long a drain valve you need until the old one is removed. One option for a replacement is to use a brass hose bib with a short iron pipe nipple to get the right length.
A better option is to replace the drain valve with a full port ball valve. The ball valve will allow for faster draining and this type of valve rarely goes bad.
- Apply Teflon tape and pipe joint compound on the threads of the new valve before screwing it into place. Both the Teflon tape and compound will help to avoid leaks.
- Screw the new drain valve into place, tighten, and make sure to position it to face the right direction.
- Refill the water heater and test for leaks. Check back several times over the next day or so to ensure that there are no slow leaks coming from the new drain valve.