Quick Answer:
If you smell a strong chlorine odor immediately after someone used the curb stop, it’s most likely disinfectant or flushed water that reached your service line. Note the timing of the odor immediately after curb stop use — that timing is the main clue. Do a few basic checks, flush cold taps, avoid hot water and appliances, and contact your water utility if the smell doesn’t go away.
Why This Happens
Water utilities sometimes disinfect or flush lines during maintenance, repairs, or when a curb stop is opened or closed. That treated water can travel into nearby service lines and cause a sudden chlorine smell at your faucets. The fact you noticed the odor right after the curb stop was used points to this kind of short-term, external source rather than a problem inside your home.
Other reasons include:
- Residual disinfectant left in the meter or service line after a repair.
- A temporary backflow or pressure change that drew treated water toward your home.
- A recent water main flush on your street.
Step-by-Step What to Do
1. Note the timing and where you smell it
- Write down when the odor started and that it began right after the curb stop was operated.
- Check which taps show the smell — all faucets, only cold, only hot, or a single fixture.
2. Test cold vs. hot water
- Run a cold tap for 1–2 minutes and smell again. If the odor is much stronger in hot water, the hot water system may hold residual chemicals.
- A short odor only from hot water suggests the heater or upstairs plumbing; see the FAQ for related notes.
3. Flush cold-water taps
- Open an outside hose bib or a basement/cold-water tap and let the water run for 5–15 minutes. Often this clears treated water from the service line.
- Do not run hot water while flushing; heated water can release more chlorine vapor and spread the smell.
4. Check with neighbors and your utility
- Ask neighbors if they smelled chlorine or had work done. If multiple homes are affected, the utility is likely responsible.
- Call your water utility’s non-emergency line, report the timing, and ask if they performed a disinfectant or flush near your curb stop.
5. Keep records and avoid using affected water
- If smell persists after flushing, document times and which fixtures are affected and request a water quality check from the utility.
- Use bottled water for drinking and cooking until the issue is resolved if the odor is strong.
What Not to Do
- Do not operate curb stops yourself.
- Do not run your water heater or use hot water baths/showers until the chlorine smell is reduced.
- Do not add chemicals or attempt to neutralize chlorine with household products — leave testing and treatment to the utility or a professional.
When to Call a Professional
- Call the water utility right away if the odor began after curb stop work and flushing does not clear it within a short time.
- Contact a licensed plumber if only your home is affected, the smell is persistent, or you suspect a backflow or equipment failure inside the house.
- Seek immediate medical attention if anyone has severe breathing trouble, dizziness, or other acute symptoms from the odor.
Safety Notes
- Avoid hot water use (showers, dishwasher) while the smell is strong; hot water releases vapors that can irritate eyes and lungs.
- Ventilate the house by opening windows if the odor enters living spaces.
- Use bottled water for drinking and cooking until you’re sure the smell is gone or testing confirms water quality.
Common Homeowner Questions
- Is the water safe to drink? If you detect a strong chlorine smell, avoid drinking until you’ve flushed cold taps and confirmed the smell is gone or the utility advises it’s safe.
- How long will the smell last? Often minutes to a few hours after flushing; if it continues longer, contact the utility or a plumber for testing.
- Why does it sometimes only come from upstairs? A smell limited to hot water or upper floors can come from the water heater or upstairs plumbing — check cold versus hot and consider the guidance on **Chemical smell only upstairs**.
If you notice changes in taste at specific times — for example when you first use water in the morning — that pattern is useful to report; **Taste worse in morning** can help the utility or plumber diagnose the source.
Related Articles
If you’re troubleshooting a similar symptom, these guides may help:
For the full directory, see Chlorine or Chemical Taste and Odor.