The answer to 'my water heater installation smells bad' is that a rotten egg or sulfur-like odor coming from your water heater is often caused by a buildup of bacteria in the tank. This can happen when the anode rod in the water heater becomes depleted, allowing hydrogen sulfide gas to form. The smell may also indicate a problem with the heating element, thermostat, or other water heater components.
To address the issue, you'll first want to check the anode rod and replace it if it's worn out. You can also try flushing the tank to remove any sediment buildup. If the smell persists, you may need to have a professional plumber inspect the water heater and make any necessary repairs or replacements.