Chlorate Contamination

Chlorate in Tennessee Drinking Water

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

Cities Tested

Over HA

74%

% Over HA

405.5 µg/L

State Avg

▲ 15% vs national

vs National

227

Health Violations

Analysis

Chlorate in Tennessee: what the data shows

Tennessee has 76 cities with chlorate data from the EPA's UCMR 3 program (2013–2015). Chlorate exceeded the 210 µg/L EPA lifetime health advisory in 56 of those cities. The state average max detected level is 405.5 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.

Comparison

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

Tennessee

74%

56 of 76 cities

→ ▲ 15% above national rate (worse)

National avg

59%

1866 of 3166 cities

City Map

Chlorate data across Tennessee

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 Tennessee

Highest Chlorate levels (µg/L)

All Cities

All Tennessee cities ranked by chlorate level

#	City	Level	Over HA?	Violations	Grade
1	Harriman	1640.0 µg/L	Over HA	13	D+
2	Pikeville	1139.0 µg/L	Over HA	51	B
3	Murfreesboro	1100.0 µg/L	Over HA	4	B+
4	Franklin	1100.0 µg/L	Over HA	25	C+
5	Franklin	1100.0 µg/L	Over HA	12	B-
6	Lebanon	910.0 µg/L	Over HA	21	C-
7	Dickson	840.0 µg/L	Over HA	1	A
8	Elizabethton	820.0 µg/L	Over HA	27	D
9	Knoxville	800.0 µg/L	Over HA	36	C-
10	Mcminnville	760.0 µg/L	Over HA	8	B+
11	Newport	700.0 µg/L	Over HA	3	A
12	Bristol	690.0 µg/L	Over HA	12	B-
13	Parsons	674.4 µg/L	Over HA	15	C+
14	Harvest	670.0 µg/L	Over HA	1	B+
15	Harvest	670.0 µg/L	Over HA	1	B+
16	Winchester	660.0 µg/L	Over HA	7	A-
17	Dyersburg	610.0 µg/L	Over HA	2	A
18	Columbia	543.5 µg/L	Over HA	9	B+
19	Counce	530.0 µg/L	Over HA	11	B
20	Loudon	520.0 µg/L	Over HA	5	B+
21	Lenoir City	491.0 µg/L	Over HA	3	B-
22	Church Hill	490.0 µg/L	Over HA	4	A-
23	Erin	480.0 µg/L	Over HA	25	B+
24	Monteagle	473.0 µg/L	Over HA	6	B
25	Nolensville	470.0 µg/L	Over HA	8	B
26	Erwin	461.0 µg/L	Over HA	27	A-
27	Pigeon Forge	440.0 µg/L	Over HA	1	A
28	Smyrna	420.0 µg/L	Over HA	9	A-
29	Soddy-Daisy	420.0 µg/L	Over HA	2	A
30	Fayetteville	400.0 µg/L	Over HA	2	D
31	Maryville	390.0 µg/L	Over HA	9	A-
32	Blountville	380.0 µg/L	Over HA	0	A+
33	Cowan	380.0 µg/L	Over HA	1	A-
34	Sevierville	370.0 µg/L	Over HA	11	D
35	Crossville	360.0 µg/L	Over HA	14	B+
36	Knoxville	359.0 µg/L	Over HA	1	A
37	Athens	352.7 µg/L	Over HA	0	A
38	Portland	350.0 µg/L	Over HA	5	A
39	Madisonville	340.0 µg/L	Over HA	6	A-
40	Lawrenceburg	330.0 µg/L	Over HA	1	B+
41	Memphis	320.0 µg/L	Over HA	4	C+
42	Johnson City	315.4 µg/L	Over HA	0	A
43	Cleveland	310.0 µg/L	Over HA	58	B
44	Harriman	310.0 µg/L	Over HA	1	B+
45	Morristown	299.8 µg/L	Over HA	6	B
46	Dandridge	280.0 µg/L	Over HA	1	B+
47	Toone	270.0 µg/L	Over HA	0	A-
48	Clarksville	250.0 µg/L	Over HA	8	B
49	Lavergne	250.0 µg/L	Over HA	9	B+
50	Dayton	250.0 µg/L	Over HA	11	B-
51	Hendersonville	240.0 µg/L	Over HA	8	A-
52	Lake City	240.0 µg/L	Over HA	2	B-
53	Decatur	240.0 µg/L	Over HA	42	A
54	Jonesborough	230.0 µg/L	Over HA	12	A-
55	Cedar Hill	214.0 µg/L	Over HA	1	A-
56	Cedar Hill	214.0 µg/L	Over HA	1	A-
57	Shelbyville	200.0 µg/L	No	28	C
58	Chattanooga	190.4 µg/L	No	25	C+
59	Kingsport	170.0 µg/L	No	6	B
60	Georgetown	157.0 µg/L	No	2	B
61	Alcoa	140.0 µg/L	No	4	A
62	Morrison	140.0 µg/L	No	7	A
63	Sweetwater	140.0 µg/L	No	2	B
64	Cookeville	112.3 µg/L	No	4	B+
65	Etowah	108.3 µg/L	No	5	D+
66	Tellico Plains	108.3 µg/L	No	0	B-
67	Manchester	80.0 µg/L	No	2	D+
68	Tullahoma	75.0 µg/L	No	0	B+
69	Hixson	74.0 µg/L	No	0	A-
70	Jacksboro	56.0 µg/L	No	7	D+
71	Germantown	51.3 µg/L	No	0	A-
72	Minor Hill	38.4 µg/L	No	31	C-
73	New Tazewell	33.0 µg/L	No	3	B+
74	Clinton	26.0 µg/L	No	1	A
75	Jackson	24.1 µg/L	No	0	A-
76	Lafayette	24.0 µg/L	No	3	A-

FAQ

Frequently asked questions about chlorate in Tennessee

Is chlorate in Tennessee tap water dangerous?

Chlorate has no federal MCL. The EPA lifetime health advisory is 210 µg/L. 56 cities in Tennessee 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 Tennessee 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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