I talked to my plumber friend. He fixed this issue for us at the family cottage.
He removed the anorod from the hot water tank. On the top of the tank, there'* a plug. Remove that plug...attached to it will be a 30" long rod, 3/4" in diameter. It'* aluminum and should be solid. Cut the rod off the plug. Reinstall the plug. You'll be good to go.
The anorod is used for community well or city water applications, not for private wells. The rod adds minerals to the water to help prevent the tank from corrosion. On a private well, there are plenty of minerals, so that rod is adding more than necessary; hence, the stink.