Worst Tap Water in America (2026)

The lowest-scoring water system rates just 0/100 on our Safety Score. These 50 systems have the most violations, contaminant exceedances, and enforcement actions.

#	Water System	State	Safety Score	Health Violations	Population	Grade
1	City of Jackson Jackson, MS	Jackson, MS	0/100	100	189,673	F
2	Newark Water Department Newark, NJ	Newark, NJ	5/100	22	294,274	F
3	Tuscaloosa Water & Sewer Tuscaloosa, AL	Tuscaloosa, AL	8/100	6	166,524	F
4	Atlanta Atlanta, GA	Atlanta, GA	10/100	5	1,089,893	F
5	Shreveport Water System Shreveport, LA	Shreveport, LA	10/100	76	192,378	F
6	Mobile, Bd. Of W&s Comm. Of the City Of Mobile, AL	Mobile, AL	16/100	4	279,000	F
7	Bjw&sa (0720003) Okatie, SC	Okatie, SC	16/100	4	145,634	F
8	Papillion, City Of Papillion, NE	Papillion, NE	32/100	3	35,000	F
9	Gilbert, Town Of Gilbert, AZ	Gilbert, AZ	33/100	3	247,600	F
10	Liberty Utilities New York - Lynbrook Merrick, NY	Merrick, NY	34/100	6	220,000	F
11	Kalamazoo Kalamazoo, MI	Kalamazoo, MI	36/100	4	192,992	F
12	Kearney, City Of Kearney, NE	Kearney, NE	37/100	3	34,000	F
13	Columbia City of (sc4010001) Columbia, SC	Columbia, SC	38/100	3	319,500	F
14	Columbus Public Water System Columbus, OH	Columbus, OH	40/100	3	1,305,946	F
15	Springfield Water and Sewer Commission Springfield, MA	Springfield, MA	40/100	27	167,954	F
16	Las Cruces Municipal Water System Las Cruces, NM	Las Cruces, NM	40/100	6	98,175	F
17	Sioux City Water Supply Sioux City, IA	Sioux City, IA	40/100	10	85,791	F
18	City of Baltimore Baltimore, MD	Baltimore, MD	44/100	3	1,600,000	F
19	Clermont Public Water System Batavia, OH	Batavia, OH	45/100	2	133,059	F
20	Fort Wayne - 3 Rivers Filtration Plant Fort Wayne, IN	Fort Wayne, IN	50/100	3	269,994	F
21	Salt Lake City Water System Salt Lake City, UT	Salt Lake City, UT	54/100	2	381,174	F
22	Lowell Regional Water Utility Lowell, MA	Lowell, MA	55/100	3	115,000	F
23	New Orleans Carrollton Water Works New Orleans, LA	New Orleans, LA	57/100	2	334,903	F
24	Aqua Pa Main System Bryn Mawr, PA	Bryn Mawr, PA	59/100	2	822,600	F
25	Roswell Municipal Water System Roswell, NM	Roswell, NM	59/100	2	54,025	F
26	Phoenix City Of Phoenix, AZ	Phoenix, AZ	60/100	2	1,695,000	D
27	Des Moines Water Works Des Moines, IA	Des Moines, IA	60/100	2	246,055	D
28	Chandler City Of Chandler, AZ	Chandler, AZ	64/100	1	247,328	D
29	Topeka, City Of Topeka, KS	Topeka, KS	64/100	1	125,963	D
30	Glen Burnie-Broadneck Millersville, MD	Millersville, MD	64/100	1	290,606	D
31	Santa Fe Water System (city Of) Santa Fe, NM	Santa Fe, NM	68/100	1	90,810	D
32	Cocoa, City Of Cocoa, FL	Cocoa, FL	70/100	1	294,039	C
33	Philadelphia Water Department Philadelphia, PA	Philadelphia, PA	70/100	0	1,600,000	C
34	Cicero Cicero, IL	Cicero, IL	70/100	1	83,000	C
35	Veolia Water New Jersey Hackensack Haworth, NJ	Haworth, NJ	70/100	1	792,713	C
36	Jersey City Mua Hoboken, NJ	Hoboken, NJ	70/100	1	262,000	C
37	Thornton City Of Thornton, CO	Thornton, CO	70/100	0	226,465	C
38	Norman Utilities Authority Norman, OK	Norman, OK	70/100	1	104,868	C
39	Gru - Murphree Wtp Gainesville, FL	Gainesville, FL	72/100	0	195,681	C
40	Cleveland Public Water System Cleveland, OH	Cleveland, OH	72/100	0	1,308,955	C
41	Chicago Chicago, IL	Chicago, IL	72/100	0	2,746,388	C
42	Denver Water Board Denver, CO	Denver, CO	72/100	0	1,287,000	C
43	Saint Paul Regional Water Services St. Paul, MN	St. Paul, MN	74/100	0	392,529	C
44	Greensboro, City Of Greensboro, NC	Greensboro, NC	75/100	0	319,588	C
45	Mesa City Of Mesa, AZ	Mesa, AZ	75/100	0	466,000	C
46	Waterbury Water Department Waterbury, CT	Waterbury, CT	75/100	0	107,271	C
47	Winston-Salem, City Of Pfafftown, NC	Pfafftown, NC	76/100	0	388,060	C
48	Berkeley County Pswd-Potomac River Martinsburg, WV	Martinsburg, WV	76/100	0	34,786	C
49	Wvawc - Huntington Dist Charleston, WV	Charleston, WV	77/100	0	98,647	C
50	Durham, City Of Durham, NC	Durham, NC	78/100	0	322,083	C

Frequently Asked Questions

The Safety Score (0-100) weighs four factors: health-based violations (40%), contaminant exceedances above EPA limits (30%), enforcement action history (20%), and monitoring compliance (10%).

Systems on this list have histories of violations, but many issues may be resolved. Check your specific system page for current status. If concerned, request your annual Consumer Confidence Report or consider a certified water filter.

All data comes from the EPA Safe Drinking Water Information System (SDWIS), which tracks violations and enforcement actions for every public water system in the United States.