You'll need to sanitize your water system, including heater, tank, and lines. Easiest is to add 1/4 cup bleach for each 10 gallons of tank capacity. Add in the 6 or 10 gals of heater capacity. Fill the fw tank, then run water at each faucet, hot and cold, until you smell the bleach. Let it sit for a couple of hours, drain, refill and flush the system. Should take care of the odor. If you have your manual it should have instructions as well.
Btw, make sure to drain the water heater of the nasty water first. Might drain the fw tank too if the water had been in there a while.