Checked by Sunni Parks ·
A rotten-egg or sulfur smell is one of the most common water complaints there is, and it's almost always about where the water has been sitting, not something added to it.
Causes and what people typically do are based on published guidance from the EPA and state drinking-water programs, not guesses. The zip lookup pulls from EPA's public violation records (SDWIS) and a utility's own water quality report, hand-checked utility by utility rather than scraped.
This tool provides general information based on published EPA and utility data, and common causes reported by water quality professionals. It is not a substitute for laboratory water testing, a licensed plumber's assessment, or guidance from your water utility or local health department. WaterCheck does not guarantee the accuracy, completeness, or timeliness of the information provided and is not liable for decisions made based on it.
Not on its own in most cases. The smell almost always traces back to bacteria reacting with either your water heater's anode rod (hot tap only) or naturally occurring sulfur bacteria in well water or household plumbing (both taps) — not something added to the water. It's typically a nuisance issue rather than a safety one.
That points to the anode rod — a metal rod inside your water heater that keeps the tank from rusting — reacting with bacteria in the tank. Swapping it for an aluminum or zinc rod instead of magnesium usually solves it, since magnesium reacts more.
Not necessarily. Groundwater often naturally carries sulfur bacteria or hydrogen sulfide gas, which is usually just a mineral characteristic of the ground in your area rather than a sign of contamination. If the smell is new or sudden, getting the well tested is still a reasonable step.
If it's coming from both hot and cold taps on a municipal supply, it's usually bacteria reacting inside your household pipes. Running the taps for a few minutes clears it in most cases; if it lingers for days, telling your utility is the next step.