50 Cities With the Worst Tap Water (2026)

US cities ranked by the population-weighted average Tap Grade of the community water systems that report them as their location.

How this is measured

Population-weighted average of the 0–100 Tap Grade scores of active community water systems (CWS) that report this city as their location (the system's own reported city_name in EPA SDWIS). Each system's score is weighted by the population it serves; the city figure is the sum of (population × score) divided by total graded population, rounded to one decimal, then mapped to a letter grade using the same A≥90 / B≥80 / C≥65 / D≥50 / F cut lines as an individual system. Only cities whose graded systems together serve at least 50,000 people are included; they are ranked from lowest weighted score (worst) upward.

Grouping is by each system’s self-reported city, which is occasionally a corporate/admin address rather than the community served. Population served can also overlap between systems. A low grade reflects reported EPA violation, lead, and PFAS data — absence of data is not scored as "clean."

#	City	Graded systems	People served	Weighted grade
1	Lauderhill, FL	1	55,000	30
2	Warrington, PA	7	60,285	37.9
3	Midland, TX	11	164,462	38.1
4	Stillwater, OK	5	59,946	42.5
5	Jackson, MS	4	218,596	44.8
6	Rio Grande, PR	3	69,370	45.1
7	Yucaipa, CA	4	60,098	47.2
8	Valdosta, GA	44	77,971	48.6
9	Georgetown, TX	2	191,729	51
10	Shreveport, LA	12	202,179	52.9
11	Ceres, CA	3	54,751	53.2
12	Battle Creek, MI	6	50,857	53.4
13	New Orleans, LA	4	387,921	53.5
14	Pflugerville, TX	1	63,464	54
15	Aguadilla, PR	3	126,047	54.1
16	Porterville, CA	9	65,537	54.1
17	Taylor, MI	1	63,409	57
18	Dayton, OH	7	150,840	57.8
19	Moore, OK	1	55,083	58
20	Mansfield, OH	19	56,519	58.4
21	Trenton, NJ	2	236,400	58.7
22	Roswell, NM	4	59,059	59.4
23	Yuma, AZ	19	161,992	59.8
24	Lancaster, PA	13	121,677	60.3
25	Pembroke Pines, FL	1	187,459	62
26	Miami Beach, FL	3	100,146	62
27	Somerset, NJ	1	57,150	62
28	Atlantic City, NJ	3	152,739	62.1
29	Shelbyville, TN	3	60,355	62.4
30	Pikeville, KY	2	53,695	62.7
31	Palm Bay, FL	1	140,750	64
32	Grand Island, NE	1	51,478	64
33	Stockton, CA	71	224,402	64.5
34	Dearborn Heights, MI	1	57,774	65
35	Bryn Mawr, PA	25	1,057,337	65.1
36	Merrick, NY	12	372,655	65.3
37	Laredo, TX	4	271,820	65.3
38	Edinburg, TX	2	256,419	65.3
39	Elgin, IL	5	116,929	65.5
40	Haworth, NJ	32	817,526	65.7
41	Bloomfield, NJ	1	53,315	66
42	Altoona, PA	3	62,795	66.1
43	Columbia, SC	116	388,046	66.2
44	Canyon Lake, TX	17	94,476	66.2
45	Clifton, NJ	4	327,465	66.7
46	West Palm Beach, FL	4	834,971	66.8
47	Monroe, LA	2	59,598	67.3
48	Allentown, PA	18	198,541	67.6
49	Pompano Beach, FL	6	280,023	68
50	Jersey City, NJ	1	262,000	68

See how the Tap Grade is calculated on the methodology page, or where the underlying data comes from on data sources. Spotted something that looks wrong? Email contact@tapgraded.com.

Source: EPA SDWIS/ECHO + UCMR5 (see Methodology) · Data as of 2026Q2 — EPA SDWA/ECHO quarterly bulk data (2026 Q2) downloaded 2026-07-16; EPA UCMR5 occurrence data downloaded 2026-07-16