I have a plastic drain valve on my water heater and after draining it and moving it to fix the floor I can not get it to stop leaking. I am wanting to replace the drain plug but am not sure how to do this. I have removed the outer drain piece do I need to remove anything else?

If heater is drained, remove valve and replace with a brass one.
Be sure to wrap threads of new valve with teflon tape.

Chuck

Chuck said it best. Purchase a brass boiler drain,(see image) and a roll of Teflon Tape. Remove the old valve , wrap a few turns of Teflon Tape around the threads and tighten in the new drain. Fill the tank, check for leaks and turn them power on. Good luck, Tom