Chemical taste after water outage

Quick Answer:

If you taste a chemical or bleach-like flavor right after service returns, it is usually temporary. Utilities sometimes add disinfectant after an outage and stagnant water in pipes can concentrate those smells. Flush your plumbing starting at the lowest fixture, avoid drinking the first-draw water, and follow the steps below to clear and check your system.

Why This Happens

After a water outage the utility company may flush or disinfect mains to protect water quality. That can leave a temporary chlorine or similar taste in household pipes. Stale water sitting in your lines, sediments, or deposits in your water heater and appliance lines can release odors when flow resumes. If you notice a Strong bleach smell in shower or a Chemical odor when washing dishes, those are common signs that disinfectant or trapped air and sediments are being flushed through your system.

Step-by-Step What to Do

1. Don’t drink the first water you run

Do not use tap water for drinking or preparing food until you’ve flushed and the water looks and smells normal.

2. Flush the lowest fixture first

Flush the lowest fixture first after outages. Open the cold-water tap on the lowest fixture in the house (often a basement spigot or lowest sink) and run it until the water is clear and the smell eases—typically a few minutes. This helps push fresh water into the system from the bottom up.

3. Work through the house

• After the lowest fixture is clear, open cold taps at sinks and outdoor hose bibs, then work upward to higher floors.
• Run each faucet for several minutes until water runs clear and odor-free.
• Flush all toilets once or twice to replace tank water.

4. Flush hot water and appliances

• Run hot water at a fixture after you’ve cleared cold water to flush the water heater—sediment in the heater can hold concentrated chemicals.
• Run dishwashers, washing machines, and ice makers through a full cycle (empty) to clear lines and replace stored water.

5. Check filters and taste test

• If you have point-of-use filters (faucet/inline/ refrigerator), replace or bypass them if they were full of standing water during the outage.
• After flushing, smell and taste test cold water. If the odor or taste remains after thorough flushing, use bottled water and move to the “When to Call a Professional” steps below.

What Not to Do

• Do not consume first-draw water after outages.
• Do not mix household cleaners to try to mask tastes or odors—this can create dangerous fumes.
• Do not assume hot water is safe to drink before flushing the heater; hot-water lines often hold stronger odors and higher concentrations.

When to Call a Professional

• The smell or taste persists after you’ve flushed every fixture and run appliances.
• You see discolored water, particles, or continuing cloudiness after flushing.
• Anyone in the home has symptoms (nausea, vomiting, or illness) that could be related to water quality.
• You suspect a leak, backflow, or contamination event in your plumbing system.

Safety Notes

• Use bottled or clearly safe water for drinking, infant formula, and cooking until water quality is normal.
• Do not rely on hot water for drinking; always test cold water first.
• If you have a health condition or a household member who is immunocompromised, err on the side of caution and avoid use until a professional confirms safety.
• Replace inline and refrigerator filters if they were exposed to stagnant water during the outage.

Common Homeowner Questions

• How long should I flush faucets? — Run cold water at each fixture until it clears and the smell is gone; often a few minutes per fixture but possibly longer for large or complex systems.
• Is the taste dangerous? — Usually it is a temporary disinfectant taste and not harmful in small amounts, but avoid drinking until the water is clear and odor-free.
• Will the water heater make the smell worse? — Yes, the heater can hold concentrated water; run hot water after cold lines are flushed to clear it.