Quick Answer:
If you smell a strong chemical or chlorinous odor right after city crews worked nearby, it is usually temporary and caused by the water system being flushed or briefly over-chlorinated as crews disinfect lines. Stop using the water for drinking until you confirm with the utility. Follow a few checks and short flushing steps, and call the utility to confirm any chlorination events.
Why This Happens
When the water system is opened, repaired, or pressurized after work, utilities often perform a disinfection step to protect public health. That can temporarily raise chlorine or other disinfectant levels and cause a noticeable odor. The smell may be stronger in hot water because the water heater concentrates volatile chemicals; if that’s the case, see Chlorine smell only in hot water. Sudden pressure changes can also stir up deposits or chemicals in service lines and cause unusual tastes and smells—see Chemical smell after pressure change.
Step-by-Step What to Do
1. Check for notices and ask neighbors
- Look for a mailed or posted notice from the utility about planned work or emergency repairs.
- Ask neighbors whether they have the same smell; if so, it’s likely the city system and not your private plumbing.
2. Call the utility
- Call the water utility to confirm any chlorination events or flushing schedules. Call the utility to confirm any chlorination events.
- Ask whether the levels used were temporary and when they expect conditions to return to normal.
3. Avoid using hot water and appliances for now
- Avoid using the water heater, dishwasher, or washing machine for cooking or laundry until the smell subsides.
- If the odor is mainly in hot water, you may need to flush or service the heater once the utility confirms levels are normal.
4. Flush your cold-water lines
- Run an outside spigot or a cold kitchen tap for several minutes to clear service lines. Start with cold taps only; cold water is less likely to carry strong odors from the heater.
- Open multiple taps at once if possible (e.g., kitchen and an outdoor hose) to speed flow through the service line.
5. Monitor and repeat if needed
- Wait a few hours after the utility confirms the event, then test drinking water by smell and taste. If odor persists, run taps again for a longer period.
- If odors return after pressure events or heavy use, note the pattern and report it to the utility.
What Not to Do
- Do not install extra filters until city flushing stabilizes. Installing point-of-use filters immediately can clog them quickly and may mask the underlying issue.
- Do not assume a gas smell is the same issue; if you smell natural gas (rotten egg odor), leave the house and call emergency services or the gas company.
- Do not try aggressive chemical treatments in your plumbing. Wait for utility guidance before using any household chemical to “neutralize” odors.
When to Call a Professional
- Call a licensed plumber if the smell is limited to your home and does not match neighbors’ reports—this could indicate a problem in your service line or water heater.
- Contact your local public health department or the utility if you or family members develop symptoms (nausea, dizziness, breathing difficulty) after using the water.
- Call emergency services if you detect a strong fuel or gas odor; that is a separate hazard and requires immediate action.
Safety Notes
- Do not drink water with a strong chemical odor until the utility confirms it is safe. Use bottled water for drinking and food prep if you are unsure.
- For washing produce, consider using bottled water or rinsing after the utility confirms normal levels. Sensitive individuals (infants, pregnant people, immunocompromised) should avoid using the water for consumption until cleared.
- Ventilate indoor areas if the odor is strong, but do not rely on air movement to remove contaminants from water—address the water supply first.
Common Homeowner Questions
- Is the water safe to drink?
If you smell chemicals, do not drink it until the utility confirms normal disinfectant levels. Use bottled water as a precaution. - How long will the smell last?
Usually a few hours to a day after flushing; your utility can give a better estimate based on the work done. - Should I run my hot water?
Hold off on using hot water for drinking or cooking until the odor clears; you can flush cold taps first and follow utility guidance for the heater.
Related Articles
If you’re troubleshooting a similar symptom, these guides may help:
For the full directory, see Chlorine or Chemical Taste and Odor.