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.

101 to 200 of 759, by people served

California utilities whose water varies in hardness, 101 to 200, 101 to 200
Utility	Based in	Serves	Hardness, mg/L	Grains per gallon
City of Petaluma	Petaluma	61,427	72 to 314	4.2 to 18.3
Monterey Park - City, Water Dept.	Monterey Park	61,096	22 to 400	1.3 to 23.4
California Water Service - Livermore	San Jose	60,414	99 to 480	5.8 to 28.1
California Water Service - Bear Gulch	San Jose	60,382	65 to 281	3.8 to 16.4
City of Gilroy	Gilroy	59,426	180 to 287	10.5 to 16.8
City of Rialto	Rialto	59,264	130 to 220	7.6 to 12.9
City of Fountain Valley	Fountain Valley	56,747	173 to 250	10.1 to 14.6
Monte Vista WD	Montclair	56,390	71 to 215	4.2 to 12.6
Alco Water Service	Salinas	56,253	164 to 300	9.6 to 17.5
Paramount - City, Water Dept.	Paramount	55,200	170 to 230	9.9 to 13.5
Cal Am - Suburban Rosemont	Sacramento	54,893	50 to 360	2.9 to 21.1
City of Ceres	Ceres	54,513	47 to 478	2.8 to 27.9
City of Arcadia	Arcadia	54,236	23 to 295	1.4 to 17.3
Lake Hemet MWD	Hemet	52,913	53 to 276	3.1 to 16.1
Yucaipa Valley Water District	Yucaipa	52,202	95 to 310	5.6 to 18.1
City of Delano	Delano	51,428	11 to 130	0.6 to 7.6
Golden State WC - Placentia/Yorba Linda	Anaheim	50,804	100 to 324	5.8 to 18.9
Cal Am - Parkway	Sacramento	50,646	59 to 355	3.4 to 20.8
Gswc - Artesia	Anaheim	50,415	130 to 279	7.6 to 16.3
San Luis Obispo Water Department	San Luis Obispo	49,534	174 to 455	10.2 to 26.6
Cal Am - Lincoln Oaks	Sacramento	48,105	25 to 250	1.5 to 14.6
Cal/Am Water Company - San Marino	Rosemead	48,065	76 to 340	4.4 to 19.9
Golden State Water Co. - Cordova	Rancho Cordova	47,366	31 to 245	1.8 to 14.3
Diablo Water District	Oakley	47,158	92 to 330	5.4 to 19.3
Cerritos - City, Water Dept.	Cerritos	46,851	170 to 217	9.9 to 12.7
City of Colton	Colton	46,525	125 to 289	7.3 to 16.9
Hawthorne - City Water Dept.	Hawthorne	46,039	171 to 255	10 to 14.9
Oildale MWC	Bakersfield	45,315	70 to 180	4.1 to 10.5
Camp Pendleton (South)	Camp Pendleton	44,555	110 to 445	6.4 to 26
Glendora - City, Water Dept.	Glendora	44,411	120 to 365	7 to 21.3
Elk Grove Water District	Elk Grove	44,065	61 to 230	3.6 to 13.5
City of Rohnert Park	Rohnert Park	43,821	36 to 340	2.1 to 19.9
Coachella Water Authority	Coachella	43,590	41 to 72	2.4 to 4.2
Mission Springs WD	Desert Hot Springs	43,484	62 to 360	3.6 to 21.1
City of San Bruno	San Bruno	42,631	154 to 318	9 to 18.6
Indian Wells Valley W.D.	Ridgecrest	41,474	11 to 110	0.6 to 6.4
Carmichael Water District	Carmichael	41,193	24 to 220	1.4 to 12.9
Soquel Creek Water District	Soquel	40,962	86 to 395	5 to 23.1
San Gabriel County WD	Rosemead	40,154	17 to 200	1 to 11.7
City of Adelanto	Adelanto	39,930	24 to 210	1.4 to 12.3
Beverly Hills - City, Water Dept.	Beverly Hills	39,922	140 to 234	8.2 to 13.7
Gswc - Claremont	San Dimas	39,776	71 to 305	4.2 to 17.8
Pico Rivera - City, Water Dept.	Pico Rivera	39,451	104 to 212	6.1 to 12.4
Marina Coast Water District	Marina	38,918	82 to 242	4.8 to 14.2
City of Lathrop	Lathrop	38,596	170 to 250	9.9 to 14.6
Tejon Castac WD - I5 & Laval Rd	Lebec	38,125	75 to 630	4.4 to 36.8
Monrovia - City, Water Dept.	Monrovia	37,931	160 to 260	9.4 to 15.2
Vaughn WC Inc	Bakersfield	37,189	5 to 155	0.3 to 9.1
Truckee - Donner PUD, Main	Truckee	36,730	38 to 100	2.2 to 5.8
Fair Oaks Water District	Fair Oaks	36,226	53 to 120	3.1 to 7
Cal Am - Antelope	Sacramento	35,617	71 to 230	4.1 to 13.5
Santa Margarita Water District - Id9	San Juan Capistrano	35,309	105 to 720	6.1 to 42.1
Fallbrook PUD	Fallbrook	35,237	1.3 to 390	0.1 to 22.8
City of Hemet	Hemet	33,591	93 to 374	5.4 to 21.8
East Niles CSD	Bakersfield	32,517	36 to 290	2.1 to 17
Golden State Water Co - Barstow	Apple Valley	32,445	170 to 290	9.9 to 17
City of Banning	Banning	31,680	50 to 200	2.9 to 11.7
La Verne, City WD	La Verne	31,334	115 to 430	6.7 to 25.1
City of Paso Robles Water Division	Paso Robles	31,176	130 to 410	7.6 to 24
City of Martinez	Martinez	31,015	61 to 134	3.5 to 7.8
South Tahoe PUD - Main	South Lake Tahoe	30,089	11 to 85	0.7 to 5
City of Atwater	Atwater	29,479	30 to 150	1.8 to 8.8
Crescenta Valley CWD	La Crescenta	28,162	140 to 360	8.2 to 21.1
City of Dinuba	Dinuba	27,641	66 to 200	3.9 to 11.7
Cws - North Garden	San Jose	27,634	41 to 230	2.4 to 13.5
Gswc - South Arcadia	San Dimas	27,430	135 to 200	7.9 to 11.7
City of Benicia	Benicia	27,131	78 to 190	4.6 to 11.1
Hi Desert WD	Yucca Valley	26,660	69 to 155	4 to 9.1
City of Hollister	Hollister	26,598	91 to 509	5.3 to 29.8
City of Galt	Galt	26,536	2.8 to 94	0.2 to 5.5
Gswc - South San Gabriel	San Dimas	26,451	110 to 235	6.4 to 13.7
City of Sanger	Sanger	26,357	27 to 330	1.6 to 19.3
Big Bear Lake Dwp - Big Bear System	Big Bear Lake	26,164	81 to 440	4.7 to 25.7
City of Reedley	Reedley	26,076	28 to 225	1.6 to 13.2
Cws - Selma	San Jose	25,651	17 to 140	1 to 8.2
City of Riverbank	Riverbank	25,625	59 to 210	3.5 to 12.3
City of South Pasadena	South Pasadena	25,329	140 to 290	8.2 to 17
Sunny Slope Water Co.	Pasadena	25,252	73 to 282	4.3 to 16.5
City of Loma Linda	Loma Linda	25,208	6.1 to 240	0.4 to 14
City of Norco	Norco	25,068	38 to 255	2.2 to 14.9
City of Seal Beach	Seal Beach	24,937	36 to 98	2.1 to 5.7
Cal - Am Water Company - Duarte	Rosemead	24,767	110 to 270	6.4 to 15.8
Liberty Utilities - Lynwood	Downey	24,649	180 to 270	10.5 to 15.8
Phelan Pinon Hills CSD	Phelan	24,509	15 to 500	0.9 to 29.2
Golden State Water Company - Bay Point	Rancho Cordova	23,765	65 to 350	3.8 to 20.5
City of Oakdale	Oakdale	23,235	53 to 123	3.1 to 7.2
Valley of the Moon Water District	El Verano	23,140	42 to 160	2.5 to 9.4
City of Corcoran	Corcoran	22,808	4.5 to 106	0.3 to 6.2
City of Wasco	Wasco	22,757	4 to 76	0.2 to 4.4
Pico WD	Pico Rivera	22,051	167 to 341	9.8 to 19.9
City of Shafter	Shafter	21,915	17 to 205	1 to 12
San Lorenzo Valley Water Dist	Boulder Creek	21,513	46 to 470	2.7 to 27.5
City of San Jacinto	San Jacinto	20,938	117 to 201	6.8 to 11.8
West Kern Water District	Taft	20,585	72 to 175	4.2 to 10.2
Norwalk - City, Water Dept.	Norwalk	20,283	120 to 511	7 to 29.9
Humboldt C.S.D.	Cutten	19,775	55 to 62	3.2 to 3.6
Arvin Community Services Dist	Arvin	19,669	38 to 160	2.2 to 9.4
Quartz Hill Water Dist.	Quartz Hill	19,322	61 to 235	3.6 to 13.7
Lamont Public Utility Dist	Lamont	19,057	120 to 265	7 to 15.5
Riverside Highland Water Company	Grand Terrace	19,053	160 to 280	9.4 to 16.4

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.

101 to 200 of 759, by people served

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