My hot water smells like a dead rat. Very strong odor. I just replaced my hot water heater and 2 weeks later it smelled as bad as ever. I AM ON CITY WATER and do not have a well. Cold water has no smell. I am at the house every 2 weeks and turn the water heater off when not there to save on electric. After 3 showers it doesn't smell until I return in a couple of weeks. Any help would be appreciated.