Symptoms · 6 min
Why does my water smell like rotten eggs?
Rotten-egg odour is usually hydrogen sulphide from wells or water heaters. How to tell the source and which treatment stack fixes it in Canada.
Looking for a lab or free test option? Find a Water Test · Not sure which system you need? Run the Water Problem Wizard for a recommended stack and installed cost ranges.
What that smell usually means
A rotten-egg smell is most often hydrogen sulphide gas. On private wells it can come from sulphur bacteria or reducing groundwater. On city water it sometimes appears only at the hot tap when the anode rod in a water heater reacts with sulphate.
Hot only vs every tap
- Hot water only: often the water heater — a plumber or water-treatment tech can confirm before you buy a whole-house sulphur system.
- Cold and hot, or outdoor taps: the well or supply needs treatment (aeration, oxidizing filter, or specialised sulphur media).
Typical fix stack
- Sediment filter
- Iron / sulphur filter or aeration
- Softener if water is also hard
- UV if bacteria is present
- Kitchen RO for drinking water taste
Next step
Run the Water Problem Wizard on WaterFilterHelp.ca or request a free quote with your postal code — we match one local well-water specialist.