After you waste your time with the bleach and still have the sulfur (rotten egg) smell, drain the heater tank, siphon out the bottom with a small hose (there will be about a pint or so of water left after normal drain) then pour white vinegar in the drain hole until it starts running out. Plug the drain and fill the tank with fresh water. Let it sit for a couple of hours, drain and flush. If the smell still exists, repeat.
2016 3500 Duramax,2010 Cruiser CF30SKP
Viet Nam Vet 70'-71'
1950 GPS (She tells me where to go!)