Cities with Best Water Quality (2026)

The top-ranked system scores 100/100 on our Safety Score. These 50 water systems have the cleanest records in the country.

#	Water System	State	Safety Score	Population	Source	Grade
1	East Bay MUD Oakland, CA	Oakland, CA	100/100	1,442,800	Surface water	A
2	Alameda County Water District Fremont, CA	Fremont, CA	100/100	344,000	Surface water	A
3	CWS - Bakersfield San Jose, CA	San Jose, CA	100/100	267,881	Surface water	A
4	Contra Costa Water District Concord, CA	Concord, CA	100/100	198,000	Surface water	A
5	Dallas Water Utility Dallas, TX	Dallas, TX	100/100	1,356,479	Surface water	A
6	City of Plano Plano, TX	Plano, TX	100/100	292,059	Surface water	A
7	City of Frisco Frisco, TX	Frisco, TX	100/100	231,910	Surface water	A
8	Chester Water Authority Chester, PA	Chester, PA	100/100	140,437	Surface water	A
9	Pa Amer Water Co Lake Scranton Wilkes Barre, PA	Wilkes Barre, PA	100/100	134,570	Surface water	A
10	North Penn Water Authority Lansdale, PA	Lansdale, PA	100/100	91,941	Surface water	A
11	Cincinnati Public Water System Cincinnati, OH	Cincinnati, OH	100/100	750,200	Surface water	A
12	Del-Co Water Company, INC. Delaware, OH	Delaware, OH	100/100	150,000	Surface water	A
13	Aurora Aurora, IL	Aurora, IL	100/100	183,000	Surface water	A
14	Grand Rapids Grand Rapids, MI	Grand Rapids, MI	100/100	273,005	Surface water	A
15	Gwinnett Co. Dept. of Water Resources Lawrenceville, GA	Lawrenceville, GA	100/100	975,000	Surface water	A
16	Cobb County Marietta, GA	Marietta, GA	100/100	695,000	Surface water	A
17	Charlotte Water Charlotte, NC	Charlotte, NC	100/100	1,163,701	Surface water	A
18	Virginia Beach, City Of Virginia Beach, VA	Virginia Beach, VA	100/100	437,994	Surface water	A
19	Newport News, City Of Newport News, VA	Newport News, VA	100/100	407,300	Surface water	A
20	Chesterfield Co Central Water System Chesterfield, VA	Chesterfield, VA	100/100	389,897	Surface water	A
21	Bellevue City Of Bellevue, WA	Bellevue, WA	100/100	317,330	Surface water	A
22	Alderwood Water District Lynnwood, WA	Lynnwood, WA	100/100	200,000	Surface water	A
23	Redmond Water System City Of Redmond, WA	Redmond, WA	100/100	163,335	Surface water	A
24	Indiana American Water - Northwest Greenwood, IN	Greenwood, IN	100/100	210,510	Surface water	A
25	South Bend Water Works South Bend, IN	South Bend, IN	100/100	115,000	Ground water	A
26	Memphis Light, Gas, & Water Memphis, TN	Memphis, TN	100/100	659,500	Ground water	A
27	Clarksville Water Department Clarksville, TN	Clarksville, TN	100/100	251,864	Surface water	A
28	Tennessee American Water Chattanooga, TN	Chattanooga, TN	100/100	211,499	Surface water	A
29	Mo American St Louis St Charles Counties Chesterfield, MO	Chesterfield, MO	100/100	1,111,000	Surface water	A
30	Kenosha Water Utility Kenosha, WI	Kenosha, WI	100/100	99,218	Surface water	A
31	Montgomery (ww&ssb of the City Of) Montgomery, AL	Montgomery, AL	100/100	276,000	Surface water	A
32	Huntsville Utilities Huntsville, AL	Huntsville, AL	100/100	262,158	Surface water	A
33	Greenville Water (2310001) Greenville, SC	Greenville, SC	100/100	396,265	Surface water	A
34	Charleston Water System (sc1010001) Charleston, SC	Charleston, SC	100/100	327,422	Surface water	A
35	Gsw&sa (sc2620004) Conway, SC	Conway, SC	100/100	247,550	Surface water	A
36	E Jefferson Ww District 1 Jefferson, LA	Jefferson, LA	100/100	275,163	Surface water	A
37	Lafayette Utilities Water System Lafayette, LA	Lafayette, LA	100/100	169,389	Ground water	A
38	Louisville Water Company Louisville, KY	Louisville, KY	100/100	764,769	Surface water	A
39	Eugene Water & Electric Board Eugene, OR	Eugene, OR	100/100	176,000	Surface water	A
40	Oklahoma City Oklahoma City, OK	Oklahoma City, OK	100/100	644,000	Surface water	A
41	Truckee Meadows Water Authority Reno, NV	Reno, NV	100/100	442,000	Surface water	A
42	North Las Vegas Utilities North Las Vegas, NV	North Las Vegas, NV	100/100	376,515	Surface water	A
43	Henderson City Of Henderson, NV	Henderson, NV	100/100	336,534	Surface water	A
44	City of Gulfport Gulfport, MS	Gulfport, MS	100/100	75,056	Ground water	A
45	Morgantown Utility Board Morgantown, WV	Morgantown, WV	100/100	64,644	Surface water	A
46	Lincoln, City Of Lincoln, NE	Lincoln, NE	100/100	296,000	Ground water	A
47	Grand Island, City Of Grand Island, NE	Grand Island, NE	100/100	51,478	Ground water	A
48	Water District 1 of Johnson Co Kansas City, KS	Kansas City, KS	100/100	482,000	Surface water	A
49	Iowa-American Wtr Co-Davenport Davenport, IA	Davenport, IA	100/100	147,720	Surface water	A
50	Ankeny, City Of Ankeny, IA	Ankeny, IA	100/100	76,207	Surface water	A

Frequently Asked Questions

Top-ranked systems have zero or near-zero health violations, no contaminant exceedances above EPA limits, clean enforcement histories, and full monitoring compliance.

Both surface water and ground water can produce excellent quality. Surface water typically requires more treatment but is closely monitored. Ground water is naturally filtered but can be affected by local contamination.

Data comes from the EPA SDWIS database and is refreshed periodically. Violation records are cumulative, so a system with a clean recent record may still show historical violations.