Rotten Egg Smell From Hot Water in Friendswood? Fix the Anode Rod
If your Friendswood hot water smells like rotten eggs but your cold water smells fine, the problem is inside your water heater — a reaction between the magnesium anode rod and sulfur-reducing bacteria.
What Is Actually Happening
Every tank water heater contains an anode rod — a sacrificial metal rod that corrodes instead of the steel tank. In water with sulfur-reducing bacteria, the magnesium reacts to produce hydrogen sulfide gas (rotten-egg smell). The smell only shows up on hot water because the reaction happens inside the heated tank.
The Fix: Swap to Aluminum-Zinc Anode Rod
Replacing the standard magnesium anode rod with an aluminum-zinc anode rod almost always eliminates the sulfur smell within 24 to 48 hours.
- Aluminum-zinc anode rod cost: $45 to $85
- Professional install labor in Friendswood: $125 to $189
- Total: $170 to $275
Alternative Fix: UV Sterilization
For well-water homes in Santa Fe, Rosharon, Danbury, and rural Alvin where sulfur-reducing bacteria are in the source water, a UV sterilization unit runs $650 to $1,250 installed.
What Does NOT Work
- Flushing the tank: temporary only
- Adding bleach: damages tank liner, voids warranty
- Water softener: softens hard water but does not kill sulfur bacteria
When to Replace the Whole Water Heater Instead
If your water heater is 10+ years old with the sulfur smell AND other end-of-life symptoms (popping noises, slower recovery, visible rust), replacing the whole unit is often smarter than a $275 anode swap on an 11-year-old tank.