National Drinking Water Database
National Drinking Water Database - Chemical Contaminants
Chlorate
Status: Unregulated - EPA has not established a maximum legal limit in tapwater for this contaminant.
Chlorate is a disinfection byproduct (unregulated chlorine dioxide byproduct), an herbicide and a pollutant from explosives.
Detected |
Found above health guidelines |
Found above legal limit |
|
|---|---|---|---|
| States | 6 |
- |
- |
| Water utilities | 44 |
- |
- |
| People Served | 11,678,518 |
- |
- |
Chlorate Exposure by State
Water utilities in 6 states have reported detecting Chlorate in treated tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies.
| State | Water Suppliers with Chlorate contamination | |
|---|---|---|
| Systems | Population | |
| California | 31 | 10,798,220 |
| Virginia | 9 | 536,066 |
| Alabama | 1 | 237,390 |
| New York | 1 | 54,269 |
| Iowa | 1 | 41,795 |
| Minnesota | 1 | 10,778 |
| Total | 44 | 11,678,518 |
The Most Polluted Communities
44 water utilities reported detecting Chlorate in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies
Ranked by highest average Chlorate level
| Rank | System | Population Served | Positive test results of total reported tests | Average Level (Range) |
|---|---|---|---|---|
| 1 | Henrico County Public Utilities Richmond, VA | 289,000 | 48 of 49 | 419.68 ppb (0 to 1062 ppb) |
| 2 | Gcwsa - Jarratt Emporia, VA | 7,190 | 21 of 21 | 402.76 ppb (134.33 to 754.33 ppb) |
| 3 | Randall-Bold Water Treatment Plant Oakley, Ca, CA | 30,000 | 9 of 9 | 380.11 ppb (55 to 690 ppb) |
| 4 | Diablo Water District Oakley, CA | 33,250 | 9 of 9 | 380.11 ppb (55 to 690 ppb) |
| 5 | Fairmont Fairmont, MN | 10,778 | 55 of 56 | 313.32 ppb (0 to 801.67 ppb) |
| 6 | San Diego County Water Authority San Diego, CA | 0 | 3 of 3 | 292.67 ppb (220 to 350 ppb) |
| 7 | Santa FE I.D. Rancho Santa Fe, CA | 20,828 | 17 of 17 | 238 ppb (21 to 389 ppb) |
| 8 | Los Angeles Department of Water and Power Los Angeles, CA | 3,828,700 | 8 of 8 | 235.5 ppb (85 to 331 ppb) |
| 9 | Cal AM Water Company - Monterey Pacific Grove, CA | 92,115 | 39 of 39 | 183.97 ppb (15 to 330 ppb) |
| 10 | Zone 7 Water Agency Livermore, CA | 195,230 | 91 of 98 | 173.66 ppb (0 to 534 ppb) |
Testing Summary for Chlorate
| Are tests routinely required for Chlorate by federal law? | No |
| Water suppliers reporting tests for Chlorate (2004-2009): | 58 of 47,576 |
| Average testing rate for water supplier reporting tests (2004-2009): | 2.3 per year |
Government, industry, academic studies and classifications
| government/industry list/academic study | appears on list as | classification(s) |
references
| government/industry list/academic study | reference |
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