Chlorine (Disinfectant) in Drinking Water
Disinfectant · MCL: 4 ppm · 1 systems exceeding limit
Overview
Chlorine is the most widely used drinking water disinfectant in the United States. While essential for public health, it can react with naturally occurring organic matter in water to form disinfection byproducts (DBPs) such as trihalomethanes and haloacetic acids. The EPA regulates both chlorine levels and DBP levels separately. The EPA Safe Drinking Water program sets and enforces the maximum contaminant levels shown here.
Health Effects
At levels above the MCL, chlorine can cause eye and nose irritation, stomach discomfort, and may increase the risk of bladder cancer through disinfection byproducts (THMs and HAAs) formed when chlorine reacts with organic matter. Most health concerns relate to byproducts rather than chlorine itself.
Sources of Contamination
Chlorine is intentionally added to drinking water as a disinfectant to kill bacteria, viruses, and other pathogens. It has been used in water treatment since the early 1900s and is responsible for virtually eliminating waterborne diseases like cholera and typhoid in the US. Over-chlorination can occur due to equipment malfunction or during emergency disinfection.
Treatment & Removal
Activated carbon filters (including basic pitcher filters and faucet-mount filters) effectively remove chlorine from drinking water. Letting water sit uncovered for 24 hours will also allow chlorine to dissipate. Whole-house carbon filters can remove chlorine at the point of entry.
How to Remove Chlorine (Disinfectant) From Water
These filtration methods are effective for reducing Chlorine (Disinfectant) in drinking water:
| Filter Method | Effectiveness | Cost Range | Certification |
|---|---|---|---|
| Activated Carbon (any type) | 95-99% removal | $20-60 (pitcher) | NSF/ANSI 42 |
| KDF Media | 95-99% removal | $100-500 (shower/whole-house) | NSF/ANSI 42 |
| Vitamin C Shower Filters | 90-99% removal | $20-40 (shower) | None standard |
Activated Carbon (any type), details
Even basic pitcher filters effectively remove chlorine taste and odor. Most affordable option.
KDF Media, details
Great for shower filters. Removes chlorine without slowing water flow.
Vitamin C Shower Filters, details
Neutralizes chlorine chemically. Popular for shower use. Requires frequent cartridge replacement.
Water Systems with Chlorine (Disinfectant) Detected
Chicago
Chicago, Illinois
Phoenix City Of
Phoenix, Arizona
Philadelphia Water Department
Philadelphia, Pennsylvania
Cleveland Public Water System
Cleveland, Ohio
Denver Water Board
Denver, Colorado
Citizens Water - Indianapolis
Indianapolis, Indiana
Metropolitan Utilities District
Omaha, Nebraska
Mesa City Of
Mesa, Arizona
Saint Paul Regional Water Services
St. Paul, Minnesota
Metropolitan District Commission
Hartford, Connecticut
Winston-Salem, City Of
Pfafftown, North Carolina
Aquarion-Eastern Fairfield County
Shelton, Connecticut
New Orleans Carrollton Water Works
New Orleans, Louisiana
Durham, City Of
Durham, North Carolina
Greensboro, City Of
Greensboro, North Carolina
Newark Water Department
Newark, New Jersey
Knoxville Utilities Board - Kub
Knoxville, Tennessee
Gilbert, Town Of
Gilbert, Arizona
Thornton City Of
Thornton, Colorado
Springfield Pws
Springfield, Missouri
Shreveport Water System
Shreveport, Louisiana
City of Jackson
Jackson, Mississippi
Wvawc - Huntington Dist
Charleston, West Virginia
Santa Fe Water System (city Of)
Santa Fe, New Mexico
Berkeley County Pswd-Potomac River
Martinsburg, West Virginia
Tuscaloosa Water & Sewer
Tuscaloosa, Alabama
Frequently Asked Questions
Chlorine (Disinfectant) has been detected in 1 water systems that exceed the EPA maximum contaminant level (MCL) of 4 ppm, affecting approximately 166,524 people. Check your local water system's annual Consumer Confidence Report or search by ZIP code on this site.
At levels above the MCL, chlorine can cause eye and nose irritation, stomach discomfort, and may increase the risk of bladder cancer through disinfection byproducts (THMs and HAAs) formed when chlorine reacts with organic matter. Most health concerns relate to byproducts rather than chlorine itself.
Effective filtration methods for Chlorine (Disinfectant) include Activated Carbon (any type), KDF Media, Vitamin C Shower Filters. Look for filters certified to NSF/ANSI standards for Chlorine (Disinfectant) removal. See the detailed comparison table above for effectiveness ratings and cost ranges.
The EPA Maximum Contaminant Level (MCL) for Chlorine (Disinfectant) is 4 ppm. The MCL Goal (MCLG), the level with no known health risk, is 4 ppm. Water systems must test regularly and notify customers if levels exceed the MCL.