Chlorate Contamination

Chlorate in Kentucky Drinking Water

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

Cities Tested

Over HA

52%

% Over HA

305.0 µg/L

State Avg

▼ 7% vs national

vs National

222

Health Violations

Analysis

Chlorate in Kentucky: what the data shows

Kentucky has 79 cities with chlorate data from the EPA's UCMR 3 program (2013–2015). Chlorate exceeded the 210 µg/L EPA lifetime health advisory in 41 of those cities. The state average max detected level is 305.0 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)

Kentucky

52%

41 of 79 cities

← ▼ 7% below national rate (better)

National avg

59%

1866 of 3166 cities

City Map

Chlorate data across Kentucky

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 Kentucky

Highest Chlorate levels (µg/L)

All Cities

All Kentucky cities ranked by chlorate level

#	City	Level	Over HA?	Violations	Grade
1	Prestonsburg	1100.0 µg/L	Over HA	11	A-
2	Lebanon	886.0 µg/L	Over HA	11	A-
3	Sedalia	878.0 µg/L	Over HA	5	B
4	Henderson	810.0 µg/L	Over HA	7	B
5	Ft. Thomas	770.0 µg/L	Over HA	0	A-
6	Leitchfield	750.0 µg/L	Over HA	9	A-
7	Grayson	750.0 µg/L	Over HA	26	B-
8	Somerset	713.0 µg/L	Over HA	4	B+
9	Franklin	710.0 µg/L	Over HA	2	A-
10	Mcdoqwell	692.0 µg/L	Over HA	26	C+
11	Pikeville	664.0 µg/L	Over HA	79	D
12	Paducah	650.0 µg/L	Over HA	4	A-
13	Mt Sterling	645.0 µg/L	Over HA	118	D
14	Catlettsburg	610.0 µg/L	Over HA	24	C-
15	Greenville	605.0 µg/L	Over HA	17	C+
16	Nicholasville	580.0 µg/L	Over HA	38	C-
17	Salt Lick	568.0 µg/L	Over HA	6	A-
18	Richmond	541.0 µg/L	Over HA	11	B
19	Liberty	528.0 µg/L	Over HA	32	C+
20	Monticello	516.0 µg/L	Over HA	7	A-
21	Grennsburg	515.0 µg/L	Over HA	11	A-
22	Campbellsville	429.0 µg/L	Over HA	25	B
23	Salvisa	428.0 µg/L	Over HA	7	B+
24	Bradenburg	420.0 µg/L	Over HA	2	A-
25	London	376.0 µg/L	Over HA	19	B-
26	Inez	364.0 µg/L	Over HA	48	B-
27	Frankfort	344.0 µg/L	Over HA	7	C+
28	Georgetown	327.0 µg/L	Over HA	3	B+
29	Ft. Campbell	320.0 µg/L	Over HA	0	C+
30	Lynch	320.0 µg/L	Over HA	11	C-
31	Mayfield	308.0 µg/L	Over HA	3	C-
32	Lawrenceburg	291.0 µg/L	Over HA	19	B
33	Bagdad	270.0 µg/L	Over HA	1	B+
34	Danville	264.0 µg/L	Over HA	10	A-
35	Cynthiana	263.0 µg/L	Over HA	29	C+
36	Bardwell	240.0 µg/L	Over HA	1	A-
37	Ashland	234.0 µg/L	Over HA	37	C+
38	Louisville	230.0 µg/L	Over HA	7	B+
39	Coxs Creek	230.0 µg/L	Over HA	7	B+
40	Radcliff	220.0 µg/L	Over HA	1	A-
41	Pineville	220.0 µg/L	Over HA	14	C+
42	Paintsville	207.0 µg/L	No	10	A-
43	Burlington	190.0 µg/L	No	6	B
44	Buckner	190.0 µg/L	No	3	A
45	Hardinsburg	187.0 µg/L	No	29	A-
46	Middlesboro	187.0 µg/L	No	1	A-
47	Irvine,	174.0 µg/L	No	11	B
48	Lancaster	167.0 µg/L	No	13	B+
49	Taylorsville	160.0 µg/L	No	1	A-
50	Mckee	160.0 µg/L	No	60	B-
51	Sharpsburg	160.0 µg/L	No	20	B
52	Lagrange	150.0 µg/L	No	0	A-
53	Greenup	124.0 µg/L	No	54	B-
54	Bardstown	120.0 µg/L	No	13	B+
55	Bloomfield	110.0 µg/L	No	13	B
56	Springfield	100.0 µg/L	No	6	A
57	Scottsville	97.2 µg/L	No	5	B+
58	Bowling Green	95.8 µg/L	No	16	B
59	Benton	94.5 µg/L	No	14	C+
60	Florence	91.0 µg/L	No	4	A
61	Glasgow	87.6 µg/L	No	3	A
62	Mt Washington	84.0 µg/L	No	1	A-
63	Fulton	69.3 µg/L	No	1	A-
64	Elizabethtown	62.0 µg/L	No	3	B+
65	Hartford	49.0 µg/L	No	77	C
66	Knottsville	40.0 µg/L	No	4	B+
67	Morehead	39.1 µg/L	No	45	C+
68	Corbin	33.3 µg/L	No	9	B
69	Flemingsburg	31.0 µg/L	No	13	B+
70	Whitley City	29.9 µg/L	No	3	A
71	Harrodsburg	29.3 µg/L	No	8	A-
72	Maysville	26.7 µg/L	No	8	B-
73	Owensboro	26.0 µg/L	No	5	A-
74	Brownsville	26.0 µg/L	No	26	D+
75	Horse Cave	25.5 µg/L	No	3	A-
76	Hazard	24.6 µg/L	No	21	B-
77	Cadiz	24.5 µg/L	No	4	B+
78	Hopkinsville	23.9 µg/L	No	15	A-
79	Winchester	23.0 µg/L	No	25	B+

FAQ

Frequently asked questions about chlorate in Kentucky

Is chlorate in Kentucky tap water dangerous?

Chlorate has no federal MCL. The EPA lifetime health advisory is 210 µg/L. 41 cities in Kentucky 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 Kentucky 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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