Chlorate in West Virginia Drinking Water
Ranked by max chlorate detected (µg/L) · UCMR 3 data (2013–2015) · Data from EPA SDWIS & UCMR
Chlorate in West Virginia: what the data shows
West Virginia has 19 cities with chlorate data from the EPA's UCMR 3 program (2013–2015). Chlorate exceeded the 210 µg/L EPA lifetime health advisory in 6 of those cities. The state average max detected level is 211.5 µg/L. Chlorate is a disinfection byproduct that forms when chlorine dioxide or hypochlorite solutions are used to disinfect drinking water. It is most common in systems that use chlorine dioxide for taste-and-odor control or that store hypochlorite for extended periods. There is no federal MCL — the EPA lifetime health advisory is 210 µg/L. Chlorate can interfere with thyroid function by blocking iodide uptake, an effect of particular concern for pregnant women, infants, and people with thyroid conditions. Reverse osmosis and ion exchange (anion-specific) are effective at removing chlorate; standard activated carbon filters provide only modest reduction.
Cities exceeding 210 µg/L EPA lifetime HA (no MCL)
Chlorate data across West Virginia
Each dot is a city with UCMR 3 chlorate testing data. Cities where chlorate exceeds the 210 µg/L EPA lifetime health advisory are highlighted. Size reflects population served.
Top 10 cities by chlorate level in West Virginia
Highest Chlorate levels (µg/L)
All West Virginia cities ranked by chlorate level
| # | City | Level | Level | Over HA? | Violations | Grade |
|---|---|---|---|---|---|---|
| 1 | Williamson | 830.0 µg/L | Over HA | 7 | D | |
| 2 | Fairview | 765.8 µg/L | Over HA | 2 | F | |
| 3 | Martinsburg | 516.0 µg/L | Over HA | 16 | F | |
| 4 | Parkersburg | 341.0 µg/L | Over HA | 8 | C | |
| 5 | Baker Heights | 333.0 µg/L | Over HA | 5 | B | |
| 6 | Vienna | 227.0 µg/L | Over HA | 1 | C- | |
| 7 | Scott Depot (Rr Name Scott) | 210.0 µg/L | No | 0 | A- | |
| 8 | Morgantown | 169.0 µg/L | No | 50 | F | |
| 9 | Clarksburg | 92.0 µg/L | No | 5 | F | |
| 10 | Moundsville | 88.0 µg/L | No | 11 | F | |
| 11 | Peterstown | 83.0 µg/L | No | 2 | A- | |
| 12 | Huntington | 68.0 µg/L | No | 1 | A- | |
| 13 | Weirton | 66.0 µg/L | No | 21 | F | |
| 14 | Fairmont | 53.4 µg/L | No | 18 | F | |
| 15 | Hinton | 49.0 µg/L | No | 0 | A- | |
| 16 | Flemington | 38.0 µg/L | No | 3 | B | |
| 17 | Worthington | 34.1 µg/L | No | 2 | F | |
| 18 | Beckley | 32.2 µg/L | No | 7 | A- | |
| 19 | St. Albans | 22.2 µg/L | No | 2 | F |
Frequently asked questions about chlorate in West Virginia
Is chlorate in West Virginia tap water dangerous?
Chlorate has no federal MCL. The EPA lifetime health advisory is 210 µg/L. 6 cities in West Virginia exceed this level. Chlorate can interfere with thyroid iodide uptake, which is a particular concern for infants, pregnant women, and people with hypothyroidism.
Where does chlorate in West Virginia water come from?
Chlorate is a byproduct of chlorine-based disinfectants — particularly chlorine dioxide and hypochlorite (bleach) solutions. Levels tend to be higher in systems that use chlorine dioxide for taste-and-odor treatment or store sodium hypochlorite at high concentrations or for long periods. Levels vary seasonally with disinfectant use.
How can I reduce chlorate exposure?
Reverse osmosis is the most effective home treatment for chlorate, typically removing 80–95%. Anion exchange systems also work but require regeneration. Standard activated carbon filters provide only limited chlorate reduction. Boiling does NOT remove chlorate.