A sharp, rotten-egg smell — especially from hot water, or right when a tap is first turned on — is almost always hydrogen sulfide gas, produced by naturally occurring sulfur bacteria in groundwater or inside a water heater.
Hydrogen sulfide gas forms when sulfur bacteria break down naturally occurring sulfate minerals in groundwater, or when sulfate-reducing bacteria build up inside a water heater's anode rod and tank. It's more common in well water than city water, and the smell is often strongest from the hot tap because heat releases more of the gas. It's unpleasant and can tarnish silverware or discolor plumbing, but at the low concentrations typically found in household water it isn't considered a direct health hazard — it's treated as a nuisance, aesthetic issue rather than a regulated contaminant.
Two filtration media working together — activated carbon adsorbs the hydrogen sulfide gas and other odor-causing compounds, while a resin stage polishes what's left, for noticeably fresher-smelling water at every tap.
Learn MoreWe'll test it for free and show you exactly what a system would remove.
At the low levels typically found in household water, hydrogen sulfide odor is considered a nuisance issue rather than a direct health hazard — but it's unpleasant, can corrode plumbing fixtures over time, and is worth testing for and treating.
Heat releases more hydrogen sulfide gas, and sulfate-reducing bacteria can live inside a water heater's tank or anode rod, so the smell is often strongest, or only present, on the hot side.
Not reliably on its own. A softener addresses hardness minerals, not hydrogen sulfide gas — a carbon and resin stage is what actually removes the odor.