Water heaters · checked 5 Oct 2026
Hot water smells like rotten eggs
Safety first
- If odor fills the room or you're unsure, leave immediately.
- Never touch switches, use flames, or use phones inside.
- From outside, call 911 and your gas utility for suspected gas.
Fix it nowSeven steps
- Proceed only if odor clearly comes from water, not room air.Suspected gas requires evacuation, not troubleshooting.
- Collect separate cold and hot samples in clean, heat-safe glasses; avoid splashes.Hot-only odor points toward the water heater.
- Move samples away from the sink; notice odor without inhaling deeply.Normal-smelling samples point toward the drain.
The other four steps
- Repeat at another faucet; record which samples smell.The pattern helps locate the source.
- Book a plumber for hot-only odor; report your sample results.Heater treatment and anode work belong with a professional.
- If cold water smells too, contact your water utility or well professional.Well water may need coliform and nitrate testing.
- Leave heater settings unchanged; do not add chemicals or remove the anode.Heat treatment risks scalding; anode removal reduces corrosion protection.
When to stop
Stop and get a plumber if:
- Odor fills the room, persists with taps off, or its source is uncertain: leave immediately. Never touch switches or use phones inside. Call 911 and your gas utility from outside.
- Anyone feels ill after inhaling fumes: move to fresh air; call Poison Control at 1-800-222-1222.
- Anyone has trouble breathing, is unconscious, or is not breathing: call 911 immediately from safety. Do not reenter to investigate.
- Hot-only odor occurs at multiple faucets or returns: stop DIY troubleshooting and arrange a plumber.
What it probably is
Sulfur bacteria inside the water heaterHot samples smell at several faucets; cold samples do not. A plumber must confirm.For a pro
Water reacting with the heater's magnesium anode rodAlso causes hot-only odor; faucet checks cannot distinguish it from bacteria.For a pro
Bacteria or buildup in a sink drainWater in a glass smells normal away from the sink.For a pro
Hydrogen sulfide or sulfur bacteria in the water supplyBoth hot and cold samples smell at several faucets, especially with well water.For a pro
Time and parts
- Time
- 5–10 minutes for source checks only; not a repair.
- Parts
- $0 for checks using existing glasses; plumber service extra.
Get it done
More than a quick fix? Vora gets quotes privately and recommends one plumber.
The plumbers we’d call in Tyler & Longview · No hot water: what to do
Checked against
- Atmos Energy — Natural Gas Safety Guide
- Minnesota Department of Health — Why Does My Water Smell Like Rotten Eggs?
- City of Columbus — Sulfurous Taste & Odor
- Poison Control — Need Immediate Assistance?
Written for Vora from these public sources and checked on 5 Oct 2026. General guidance, not a substitute for a pro on site. In danger, leave and call 911.