HAA5 Contamination

HAA5 in Louisiana Drinking Water

Ranked by average HAA5 concentration (µg/L) · UCMR 4 data (2018–2020) · Data from EPA SDWIS & UCMR

Cities Tested

Exceeds Limit

% Exceeds Limit

16.0 µg/L

State Avg

▲ 1% vs national

vs National

303

Health Violations

Analysis

HAA5 in Louisiana: what the data shows

Louisiana has 63 cities with HAA5 monitoring data from the EPA's UCMR 4 program (2018–2020). Haloacetic acids (HAA5) form when chlorine-based disinfectants react with natural organic matter in water. The state average is 16.0 µg/L — worse than the 15.5 µg/L national average. 1 city exceeds the EPA MCL of 60 µg/L. HAA5 is a group of five chlorinated and brominated acetic acids. Long-term exposure above the MCL is associated with increased cancer risk and adverse reproductive outcomes. The EPA classifies total HAA5 as a probable human carcinogen at elevated concentrations. Activated carbon filtration (especially granular or block carbon) is effective at reducing HAA5. Running water through a refrigerator filter or letting it sit in an open pitcher for 30 minutes also helps, as some HAA5 species are volatile. Boiling does not remove disinfection byproducts and may concentrate them.

Comparison

Cities exceeding 60 µg/L EPA MCL

Louisiana

1 of 63 cities

→ ▲ 1% above national rate (worse)

National avg

23 of 4420 cities

City Map

HAA5 data across Louisiana

Each dot is a city with UCMR 4 HAA5 testing data. Cities where average HAA5 exceeded the 60 µg/L EPA MCL are highlighted. Size reflects population served.

Worst Offenders

Top 10 cities by haa5 level in Louisiana

Highest HAA5 levels (µg/L)

All Cities

All Louisiana cities ranked by haa5 level

#	City	Level	Exceeds?	Violations	Grade
1	Logansport	90.9 µg/L	Yes	28	C-
2	Monroe	58.6 µg/L	No	64	F
3	Tioga	48.1 µg/L	No	7	A-
4	Napoleonville	44.8 µg/L	No	27	A-
5	Gretna	44.3 µg/L	No	19	A-
6	Thibodaux	41.6 µg/L	No	27	A-
7	Belle Chasse	39.6 µg/L	No	112	F
8	Shreveport	38.2 µg/L	No	69	F
9	Luling	36.0 µg/L	No	2	A-
10	Chalmette	35.6 µg/L	No	23	A-
11	Calhoun	33.2 µg/L	No	36	C-
12	Barksdale Afb	32.2 µg/L	No	16	A
13	Jefferson	31.4 µg/L	No	2	A-
14	Cecilia	25.7 µg/L	No	11	B-
15	Natchitoches	24.3 µg/L	No	20	A
16	Lockport	24.1 µg/L	No	4	A+
17	New Orleans	22.5 µg/L	No	27	F
18	Slidell	22.2 µg/L	No	73	F
19	Morgan City	20.9 µg/L	No	20	B
20	Ferriday	20.8 µg/L	No	259	F
21	Blanchard	20.6 µg/L	No	26	B+
22	Houma	15.9 µg/L	No	6	B+
23	West Monroe	15.2 µg/L	No	443	D+
24	Baton Rouge	14.6 µg/L	No	30	F
25	Laplace	14.3 µg/L	No	89	D+
26	Baker	13.3 µg/L	No	2	A-
27	Benton	13.2 µg/L	No	43	F
28	Deville	12.3 µg/L	No	1	A
29	Maurice	12.1 µg/L	No	15	C+
30	Lawtell	10.3 µg/L	No	11	A-
31	Pineville	10.2 µg/L	No	15	F
32	Abbeville	9.4 µg/L	No	10	B+
33	Bossier City	8.8 µg/L	No	109	F
34	St. Francisville	8.7 µg/L	No	9	B+
35	Jennings	6.8 µg/L	No	10	B+
36	Alexandria	6.6 µg/L	No	113	F
37	Welsh	5.7 µg/L	No	5	A-
38	Lake Charles	5.7 µg/L	No	63	F
39	Stonewall	5.5 µg/L	No	1	A-
40	Sulphur	5.5 µg/L	No	24	B+
41	Opelousas	5.4 µg/L	No	28	C-
42	Parks	5.2 µg/L	No	15	C
43	Denham Springs	4.8 µg/L	No	6	B
44	Ruston	4.3 µg/L	No	20	B
45	Longville	3.9 µg/L	No	5	A-
46	Fordoche	3.8 µg/L	No	2	B-
47	Mandeville	3.4 µg/L	No	170	F
48	Lafayette	3.3 µg/L	No	42	F
49	Duson	3.2 µg/L	No	12	C-
50	Clarks	3.0 µg/L	No	6	C
51	Covington	2.9 µg/L	No	93	F
52	Sunset	2.4 µg/L	No	21	C+
53	Plaquemine	2.1 µg/L	No	26	C-
54	Hammond	1.9 µg/L	No	96	F
55	Zachary	1.7 µg/L	No	8	B-
56	Arnaudville	1.3 µg/L	No	44	C
57	Minden	0.9 µg/L	No	40	F
58	Gonzales	0.9 µg/L	No	16	A-
59	Bogalusa	0.5 µg/L	No	24	D
60	Oakdale	0.4 µg/L	No	29	D
61	Bastrop	0.2 µg/L	No	46	F
62	Deridder	0.1 µg/L	No	4	B+
63	Walker	0.1 µg/L	No	7	A-

FAQ

Frequently asked questions about haa5 in Louisiana

What is HAA5 and why does it appear in Louisiana tap water?

HAA5 (haloacetic acids) are disinfection byproducts that form when chlorine reacts with naturally occurring organic matter in source water. They are a normal byproduct of the disinfection process that makes water safe to drink. 1 cities in Louisiana exceed the EPA MCL of 60 µg/L. The state average is 16.0 µg/L.

How can I reduce HAA5 exposure from Louisiana drinking water?

Activated carbon filters (granular or block) effectively reduce HAA5. Refrigerator filters and under-sink carbon systems are convenient options. Unlike lead or PFAS, HAA5 levels can also be reduced by letting water stand in an open container, as some species evaporate. Boiling does NOT remove HAA5 and can concentrate them by reducing water volume.

Which Louisiana cities have the highest HAA5 levels?

The cities with the highest average HAA5 concentrations in Louisiana are: Logansport (90.9 µg/L), Monroe (58.6 µg/L), Tioga (48.1 µg/L), Napoleonville (44.8 µg/L), Gretna (44.3 µg/L). Note: this data is from UCMR 4 testing (2018–2020) and may not reflect current levels.

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