Disinfection byproducts
Chlorite in U.S. tap water
68 public water systems across 17 U.S. states report Chlorite in their annual Consumer Confidence Report. 16 sit at or above the federal limit.
At or above the federal limit (16)
| Water system | Measured | vs. limit |
|---|---|---|
| Mcallen, TX 2024 annual report | 2024 mg/L | 2530.0× the limit |
| St Petersburg, FL 2024 annual report | 1–24 mg/L | 30.0× the limit |
| Antioch, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| City of Antioch, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| City of Brentwood, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| City of Brentwood, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| City of Martinez, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| City of Martinez, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| City of Pittsburg, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| City of Pittsburg, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| Concord, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| Diablo Water District, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| Diablo Water District, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| Golden State Water Company, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| Golden State Water Company, CA 2024 annual report | 0.2 mg/L | 4.0× the limit |
| Columbia, SC 2024 annual report | 1.32 | 1.3× the limit |
Approaching the limit (5)
| Water system | Measured | vs. limit |
|---|---|---|
| Mobile, AL 2024 annual report | 0.78 | 1.0× the limit |
| Montgomery, AL 2024 annual report | 0.97 | 1.0× the limit |
| Charleston, SC 2024 annual report | 0.87 | 0.9× the limit |
| North Charleston, SC 2024 annual report | 0.87 | 0.9× the limit |
| Brownsville, TX 2024 annual report | 0.81 mg/L | 0.8× the limit |
Within the federal limit (45)
| Water system | Measured |
|---|---|
| Akron, OH 2024 annual report | 0.15–0.64 mg/L |
| Keswick Multi Care Center, MD 2024 annual report | 0.49 mg/L |
| Avondale, AZ 2024 annual report | 0–0.6 mg/L |
| Corpus Christi, TX 2024 annual report | 0.59 mg/L |
| Little Rock, AR 2024 annual report | 300–428 ug/L |
| Lakewood, NJ 2025 annual report | 0.39 mg/L |
| Glendale, AZ 2024 annual report | 0.48 mg/L |
| Aurora, CO 2024 annual report | 0.47 mg/L |
| Centennial, CO 2023 annual report | 0.47 mg/L |
| Escondido, CA 2024 annual report | 0.47 mg/L |
| Chula Vista Sweetwater, CA 2024 annual report | 0.02–0.426 mg/L |
| Sugar Land, TX 2024 annual report | 0.34 mg/L |
| San Diego, CA 2023 annual report | 0.42 mg/L |
| Lynn, MA 2024 annual report | 0.4 mg/L |
| Fayetteville, AR 2024 annual report | 300–314 ug/L |
| Mesa, AZ 2024 annual report | 0.36 mg/L |
| West Jordan, UT 2024 annual report | 0.36 mg/L |
| West Valley City, UT 2024 annual report | 0.36 mg/L |
| Lubbock, TX 2024 annual report | 0.325 mg/L |
| Phoenix, AZ 2025 annual report | 0.3 mg/L |
| Columbus, GA 2024 annual report | 0.07–0.28 |
| Louisville, KY 2024 annual report | 0.23 mg/L |
| Mckinney, TX 2024 annual report | 0.187 mg/L |
| Mesquite, TX 2024 annual report | 0.187 mg/L |
| Plano, TX 2024 annual report | 0.187 mg/L |
| Richardson, TX 2024 annual report | 0.16 mg/L |
| Yuma, AZ 2025 annual report | 0.05 mg/L |
| Knoxville, TN 2024 annual report | 0.02–0.02 |
| Houston, TX 2023 annual report | 0.002 mg/L |
| Brown Deer, WI 2024 annual report | 0 mg/L |
| Butler, WI 2024 annual report | 0 mg/L |
| Franklin, WI 2024 annual report | 0 mg/L |
| Greendale, WI 2024 annual report | 0 mg/L |
| Greenfield, WI 2024 annual report | 0 mg/L |
| Hales Corners, WI 2024 annual report | 0 mg/L |
| Menomonee Falls, WI 2024 annual report | 0 mg/L |
| Mequon, WI 2024 annual report | 0 mg/L |
| Milwaukee, WI 2024 annual report | 0 mg/L |
| New Berlin, WI 2024 annual report | 0 mg/L |
| Shorewood, WI 2024 annual report | 0 mg/L |
| St. Francis, WI 2024 annual report | 0 mg/L |
| Thiensville, WI 2024 annual report | 0 mg/L |
| Waukesha, WI 2024 annual report | 0 mg/L |
| Wauwatosa, WI 2024 annual report | 0 mg/L |
| West Allis, WI 2024 annual report | 0 mg/L |
Frequently asked
+What is Chlorite?
Chlorite is a contaminant some U.S. public water utilities measure and report in their annual Consumer Confidence Report.
+What is the federal limit for Chlorite in drinking water?
The federal MCLG for Chlorite is 0.8 mg/L. The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.
+How many U.S. water systems have Chlorite over the federal limit?
16 of the 68 public water systems on The Water Map report Chlorite at or above its federal limit, spanning 17 U.S. states. The full list is on this page.
+How can I check if Chlorite is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including Chlorite.