Chlorate Contamination

Chlorate in Arkansas Drinking Water

Ranked by max chlorate detected (µg/L) · UCMR 3 data (2013–2015) · Data from EPA SDWIS & UCMR

Cities Tested

Over HA

38%

% Over HA

319.8 µg/L

State Avg

▼ 21% vs national

vs National

311

Health Violations

Analysis

Chlorate in Arkansas: what the data shows

Arkansas has 34 cities with chlorate data from the EPA's UCMR 3 program (2013–2015). Chlorate exceeded the 210 µg/L EPA lifetime health advisory in 13 of those cities. The state average max detected level is 319.8 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.

Comparison

Cities exceeding 210 µg/L EPA lifetime HA (no MCL)

Arkansas

38%

13 of 34 cities

← ▼ 21% below national rate (better)

National avg

59%

1866 of 3166 cities

City Map

Chlorate data across Arkansas

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.

Worst Offenders

Top 10 cities by chlorate level in Arkansas

Highest Chlorate levels (µg/L)

All Cities

All Arkansas cities ranked by chlorate level

#	City	Level	Over HA?	Violations	Grade
1	Hope	1390.0 µg/L	Over HA	57	F
2	Searcy	1229.9 µg/L	Over HA	2	A-
3	Magnolia	1100.0 µg/L	Over HA	32	C+
4	Stuttgart	842.0 µg/L	Over HA	15	A-
5	Jacksonville	755.0 µg/L	Over HA	7	A+
6	Batesville	717.3 µg/L	Over HA	65	D+
7	Malvern	430.0 µg/L	Over HA	19	B+
8	Mabelvale	415.0 µg/L	Over HA	0	A-
9	Little Rock	358.0 µg/L	Over HA	44	C+
10	Bryant	315.0 µg/L	Over HA	6	A+
11	Pine Bluff	276.0 µg/L	Over HA	5	A-
12	Rosston	260.0 µg/L	Over HA	44	D
13	Farmington	220.0 µg/L	Over HA	15	B+
14	Conway	196.0 µg/L	No	14	B
15	Benton	190.0 µg/L	No	10	A
16	Mountain Home	176.0 µg/L	No	22	B+
17	West Memphis	175.0 µg/L	No	12	A
18	Vilonia	169.0 µg/L	No	2	A
19	Heber Springs	168.0 µg/L	No	2	A
20	Centerton	165.0 µg/L	No	4	A
21	Lincoln	160.0 µg/L	No	5	A+
22	Bentonville	151.0 µg/L	No	2	A-
23	Fayetteville	136.0 µg/L	No	17	D
24	Rogers	131.0 µg/L	No	17	B-
25	Bella Vista	130.0 µg/L	No	13	B+
26	Springdale	127.0 µg/L	No	2	B
27	Russellville	91.3 µg/L	No	25	C-
28	Hickory Ridge	85.7 µg/L	No	14	B
29	Jonesboro	66.3 µg/L	No	2	A+
30	Russelville	65.8 µg/L	No	11	A-
31	Greenwood	58.7 µg/L	No	93	D+
32	Greers Ferry	57.2 µg/L	No	6	A
33	Berryville	41.0 µg/L	No	7	A-
34	Morrilton	24.4 µg/L	No	7	B+

FAQ

Frequently asked questions about chlorate in Arkansas

Is chlorate in Arkansas tap water dangerous?

Chlorate has no federal MCL. The EPA lifetime health advisory is 210 µg/L. 13 cities in Arkansas 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 Arkansas 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.

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