Quick Answer:
If you taste chlorine right after changing a cartridge, don’t panic. New cartridges often need flushing and you should briefly bypass the new filter to check whether water is passing through the cartridge media. If flushing and a bypass test show the same taste, the problem is likely with supply water or installation; if taste disappears when bypassed, the new cartridge or how it was installed is the likely cause.
Why This Happens
There are a few common reasons for a sudden chlorine taste after a replacement:
- New filters often contain air pockets and manufacturing residues that need several minutes of flushing before they work normally.
- If the cartridge was not seated or sealed correctly, some water can bypass the carbon media and remain chlorinated.
- Some systems use protective packaging or a cap over the carbon that must be removed—if that was missed or damaged, the cartridge won’t treat water.
- Changes in your water supply or treatment at the utility can increase chlorine levels temporarily.
If you’ve recently made other changes, you might find related issues explained in Chemical smell after pressure change or Chemical taste after installing smart shutoff.
Step-by-Step What to Do
Step 1 — Stop using suspect water for drinking until checked
Use bottled or boiled water for drinking and cooking until you confirm the taste is gone or safe.
Step 2 — Flush the new cartridge per the manufacturer’s instructions
Run cold water through the new filter for the recommended time or volume (typically several minutes or a few gallons). This removes trapped air and loose carbon fines that can cause odd tastes.
Step 3 — Bypass the new filter briefly and retest taste
Temporarily bypass the filter so water flows around the cartridge, then taste a small amount. This test helps identify whether water is entering the house already chlorinated or if the filter is the issue. If the taste is gone when bypassed, water is being treated differently when it flows through the cartridge or the cartridge is blocking flow incorrectly.
Step 4 — Inspect the cartridge and housing
- Turn off water and relieve pressure before opening the housing.
- Check that the cartridge is the correct model, oriented properly, and fully seated.
- Inspect O-rings and seals for damage or debris and re-lubricate with food-grade silicone if needed.
Step 5 — Retest after reseating or replacing the cartridge
After reseating or replacing a suspect cartridge, flush again and taste. If the bypass test showed no taste but the cartridge does, try a different cartridge from the same batch if possible.
Step 6 — Check supply and follow-up
If bypassing still shows chlorine taste, contact your water utility to ask about recent chlorination changes. Keep notes on when the taste started and any recent plumbing work to help troubleshooting.
What Not to Do
- Do not discard filters until bypass testing is done. You may need the original cartridge for inspection or warranty claims.
- Do not use bleach, solvents, or household chemicals to “clean” a cartridge or housing.
- Do not force a cartridge into place—forcing can damage seals and lead to bypass flow.
When to Call a Professional
- If you’ve bypassed and flushed but the taste persists or water looks cloudy.
- If you find a torn O-ring, damaged housing, or you are unsure how to reseat the cartridge safely.
- If multiple fixtures show unusual tastes or other signs of contamination.
Safety Notes
- Always shut off supply and relieve pressure before opening filter housings.
- Wear gloves if you handle used cartridges—waste can contain captured contaminants.
- Follow manufacturer disposal instructions for used cartridges and packaging.
Common Homeowner Questions
- Why does a new carbon filter taste odd at first? New filters often release harmless carbon fines and trapped air; flushing usually fixes it.
- How long should I flush a new cartridge? Follow the manufacturer’s guidance—typically several minutes or a few gallons of water.
- Can a bad install cause chlorine taste? Yes. If water bypasses the media because the cartridge or seal is misaligned, treated water won’t pass through the carbon.
Related Articles
If you’re troubleshooting a similar symptom, these guides may help:
For the full directory, see Chlorine or Chemical Taste and Odor.