Where the smell is tells you where it comes from
| Where you notice it | Likely cause |
|---|---|
| Hot water only | Water heater anode rod reaction |
| Both hot and cold, on a well | Hydrogen sulfide in the groundwater |
| Sprinklers, wet walls outdoors | Irrigation well water |
| One sink or shower drain | The drain, not the water |
The water heater explanation
Tank water heaters use a sacrificial anode rod, often magnesium. In warm water that sits, bacteria can react with the rod and produce hydrogen sulfide. WASD's chloramine is meant to keep the distribution system disinfected, but a heater that sits unused, like a guest bath or a house closed up for the summer, can still develop the smell. A plumber can flush the tank or change the rod type; check the heater manufacturer's guidance first.
Quick checks you can do today
- Run cold water at the kitchen tap for a minute and smell it. Then do the same with hot.
- Fill a glass and step away from the sink, so you're not smelling the drain.
- Note whether the smell is worse first thing in the morning or after a trip.
- Check whether your sprinklers run from a well or the county meter.
Write down what you find; it speeds up the visit.
Irrigation wells and septic yards
Some South Miami yards water from a shallow irrigation well. That water is untreated and can carry sulfur odor and iron. Miami-Dade's watering rules apply to wells too: odd-numbered addresses Wednesday and Saturday, even-numbered Thursday and Sunday, before 10 a.m. and after 4 p.m. The smell outdoors does not mean your tap water is affected. Separately, the city notes large parts of South Miami still use septic; a smell near a drain field is a septic question, not a water one.
Treatment options
- Water heater: fix at the heater; a filter usually won't stop it.
- Private drinking well: aeration, oxidation and filtration chosen from the well's test. See aeration vs. filtration for sulfur smells.
- Irrigation well: treatment on the irrigation line if the odor or stains bother you.
What Jorge checks
Hot and cold taps side by side, chloramine, pH and iron, the water heater's age and type, and whether you have a well. If the heater is the cause, he will tell you, and you may not need a filter. Call, text or WhatsApp (305) 793-5974.
https://www.miamidade.gov/global/water/conservation/outdoor-water-restrictions.page
https://www.southmiamifl.gov/806/Septic-to-Sewer-Information
Updated 2026-10-17 · Living Waters · Jorge Canela, Water Quality Specialist