California utilities whose water varies in hardness.

Water in more than one band, depending on where or when it was sampled: each is given as its range, softest to hardest. 759 utilities serving 28 million people as they report it, largest first.

501 to 600 of 759, by people served

California utilities whose water varies in hardness, 501 to 600, 501 to 600
Utility	Based in	Serves	Hardness, mg/L	Grains per gallon
Woodland Park Mutual Water Co	Arroyo Grande	538	170 to 190	9.9 to 11.1
Gabilan WC	Salinas	535	169 to 217	9.9 to 12.7
Allensworth CSD	Earlimart	531	97 to 250	5.7 to 14.6
Willowside Mutual Water Company	Santa Rosa	528	30 to 91	1.8 to 5.3
Cazadero Water Company, Inc. (Puc)	Forestville	525	57 to 140	3.3 to 8.2
Santa Lucia Preserve WS	Carmel	524	2.5 to 435	0.1 to 25.4
Colusa Co. Wwd #1 - Grimes	Grimes	512	50 to 317	2.9 to 18.5
Circle Oaks Water District	Napa	500	55 to 60	3.2 to 3.5
Knoll Enterprises	Ludlow	500	4.2 to 350	0.2 to 20.5
Lsid - Tonyville	Lindsay	500	8.7 to 350	0.5 to 20.5
Sky Forest MWC	Sky Forest	492	115 to 130	6.7 to 7.6
Westhaven C.S.D.	Trinidad	490	17 to 120	1 to 7
Rancheritos MWC	Apple Valley	487	78 to 170	4.6 to 9.9
CSA 70 W - 4 Pioneertown	San Bernardino	474	48 to 130	2.8 to 7.6
Belleview Oaks Mutual Water Co	Sonora	468	52 to 202	3.1 to 11.8
Glenwood Mobile Estates	Los Angeles	468	55 to 70	3.2 to 4.1
Canyon Meadows Mutual Water	Bodfish	465	155 to 250	9.1 to 14.6
Loma Linda University	Loma Linda	455	44 to 200	2.5 to 11.7
Colusa Co. Service Area #1 - Century Ranch	Colusa	450	49 to 554	2.8 to 32.4
County Service Area 11	Redwood City	450	109 to 148	6.3 to 8.6
Glen Martin MWC	Angelus Oaks	450	100 to 130	5.8 to 7.6
Antelope Park Mutual Water Company	Lancaster	445	46 to 87	2.7 to 5.1
Coast Springs - Cal. Water Service (Puc)	San Jose	445	77 to 130	4.5 to 7.6
MI Wuk Heights MWC	MI Wuk Village	445	53 to 71	3.1 to 4.2
City of Tehama	Tehama	436	85 to 133	5 to 7.8
Yolo Co Housing Authority - El Rio Villa	Woodland	432	90 to 270	5.3 to 15.8
Morada Estates N PWS #46	Stockton	426	112 to 263	6.5 to 15.4
Ward Well Water Company	Tahoe City	425	60 to 91	3.5 to 5.3
USMC - Housing Coleville	Bridgeport	424	140 to 185	8.2 to 10.8
Slide Inn Snowbowl Water Co	Sonora	417	40 to 66	2.4 to 3.8
White Oak Mutual Water Company	Cottonwood	415	58 to 62	3.4 to 3.6
Snowcrest Heights Imp Assoc	Mount Baldy	403	180 to 250	10.5 to 14.6
Las Cumbres Mutual Water Co	Los Gatos	402	9 to 228	0.5 to 13.3
Hometown Colonial Estates LLC	Rancho Cordova	400	34 to 116	2 to 6.8
Twin Lakes Resort	La Mesa	400	16 to 180	0.9 to 10.5
San Andreas Mutual Water Co	La Selva Beach	392	120 to 190	7 to 11.1
Colusa Co. Wwd #2 - Princeton	Princeton	382	160 to 230	9.4 to 13.5
Pine Hills Mutual Water Company	Julian	380	144 to 437	8.4 to 25.6
Western Acres Mutual Water Company	Hanford	380	42 to 130	2.4 to 7.6
Sereno del Mar Water Company (Puc)	Forestville	375	120 to 205	7 to 12
Black Rascal Water Company	Merced	367	140 to 271	8.2 to 15.8
Golden State Water Morongo Delnorte	Apple Valley	366	180 to 210	10.5 to 12.3
Davenport County Sanitation	Santa Cruz	350	60 to 62	3.5 to 3.6
Green River Mutual Water Co.	Paso Robles	350	110 to 170	6.4 to 9.9
Sunset West Community LLC	Seaside	350	175 to 210	10.2 to 12.3
Cal Am - Raymond	Sacramento	347	109 to 180	6.4 to 10.5
Leisure Pines Mutual Water Co	Twain Harte	340	53 to 120	3.1 to 7
Ponderosa CSD	Springville	340	36 to 66	2.1 to 3.9
Muir Beach Community	Muir Beach	336	110 to 170	6.4 to 9.9
Delta Mutual Water Company	Oakley	333	176 to 244	10.3 to 14.3
Sierra Moon Mutual Water Company	Chico	330	21 to 104	1.2 to 6.1
Sonoma County CSA 41 - Salmon Creek	Santa Rosa	327	84 to 140	4.9 to 8.2
Bel Air Mobile Estate	Stockton	325	160 to 406	9.4 to 23.7
El Capitan Mutual Water Company	Goleta	325	104 to 709	6.1 to 41.5
Leisure Lake Mobile Estates	Chandler	325	145 to 250	8.5 to 14.6
Double L Mobile Estates	Lockeford	320	90 to 150	5.3 to 8.8
Live Oak Springs Water System	Spring Valley	317	95 to 131	5.6 to 7.7
Twin Valley Inc	Castroville	317	12 to 272	0.7 to 15.9
Cascade Estates	Larkspur	316	112 to 154	6.5 to 9
Pine Mountain Mutual Water Co.	Willits	310	34 to 79	2 to 4.6
Easton Estates Water Company	Fresno	302	88 to 127	5.1 to 7.4
Big Pine Tract	Yucaipa	300	115 to 140	6.7 to 8.2
Branger Mutual Water Company, Inc.	Santa Rosa	300	173 to 188	10.1 to 11
East Walnut Grove [sws]	Sacramento	300	45 to 70	2.6 to 4.1
Glenhaven Mutual Water Company	Glenhaven	300	157 to 184	9.2 to 10.8
Holland Heights Mutual Water Company	Santa Rosa	300	180 to 200	10.5 to 11.7
Lupin Lodge	Los Gatos	300	40 to 183	2.3 to 10.7
Mariposa Pines Mutual	Mariposa	294	57 to 123	3.3 to 7.2
North Peak Mutual Water Company	Julian	294	179 to 191	10.5 to 11.1
Rancho del Campo Water System	Spring Valley	290	160 to 236	9.4 to 13.8
Belmont Terrace Mutual Water Company	Sebastopol	287	31 to 115	1.8 to 6.7
Oid #51 - Sunset Oaks #10	Oakdale	287	113 to 138	6.6 to 8.1
Hornbrook C.S.D.	Hornbrook	280	12 to 118	0.7 to 6.9
Prunedale MWC	Salinas	277	103 to 131	6 to 7.7
Shasta CSA - Sugarloaf, #2	Redding	274	9 to 142	0.5 to 8.3
Enos Lane Public Utility District	Bakersfield	270	14 to 105	0.8 to 6.1
Oid #46 - Sunset Oaks	Oakdale	269	60 to 195	3.5 to 11.4
Hood Water Maintence Dist [sws]	Sacramento	267	165 to 320	9.6 to 18.7
Ridgewood Water System	Willits	265	112 to 156	6.5 to 9.1
Sierra Village Mutual Water Co	Twain Harte	264	93 to 146	5.4 to 8.5
June Lake PUD Village	June Lake	263	18 to 72	1.1 to 4.2
Eleven Oaks Mobile Home Community	North Highlands	262	28 to 115	1.6 to 6.7
Irish Beach Water District	Manchester	254	66 to 430	3.9 to 25.1
Mountain View Mobile Estates, LLC	Newport Beach	250	142 to 307	8.3 to 18
Ocean'S Edge Estates	Fort Bragg	250	37 to 68	2.2 to 4
Park Heights Mutual Water Co	Modesto	250	148 to 199	8.7 to 11.6
Sierra Cedars CSD	Shaver Lake	250	15 to 110	0.9 to 6.4
Cws - Onyx Water System	San Jose	246	141 to 200	8.3 to 11.7
College Park Mutual Water Company	Penngrove	244	130 to 200	7.6 to 11.7
Cws - Upper Bodfish Water System	San Jose	244	109 to 127	6.4 to 7.4
Department of Water and Power	Big Bear Lake	239	57 to 190	3.3 to 11.1
Twin Oaks Mobile Park	Stockton	238	134 to 209	7.8 to 12.2
North Oaks Mutual Water Co	Oakdale	234	58 to 91	3.4 to 5.3
Dogwood Blue Jay Cyn Imp	Blue Jay	232	29 to 100	1.7 to 5.8
CSA No. 31 Stonegate WS	Hollister	230	108 to 444	6.3 to 26
Ananda Village	Nevada City	226	58 to 69	3.4 to 4
Lucerne Vista MWC	Lucerne Valley	224	115 to 145	6.7 to 8.5
Pine Cove Rv Park	Camas	223	126 to 202	7.4 to 11.8
Paradise Lake Mutual Water Co.	Salinas	213	54 to 71	3.2 to 4.1
Oak Trail Estates	Santa Ynez	211	180 to 290	10.5 to 17

Source: California State Water Resources Control Board, Division of Drinking Water, 2,449 utilities, results from Jan. 2, 2019 to July 14, 2026, read Oct. 10, 2026. Each sampling point is taken at its median; a figure is typical where every point falls in one band.

Also: 7 utilities’ own water quality reports, read by hand, each named on the utility’s page.

Bands are the U.S. Geological Survey’s, at 17.1 mg/L to the grain. People served is what each utility reports; where one sells water to another, the same people can be counted twice. How hardness is measured here.

501 to 600 of 759, by people served

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