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County drinking water records

San Luis Obispo County, CA drinking water systems

71 community water systems serve San Luis Obispo County, CA, reporting 268,460 people served in all. A system that also serves other counties counts all of its customers here.

18 of them (25%) had at least one health-based violation in the last 10 years. 3 systems still have one unresolved.

46 rely mainly on groundwater and 25 on surface water, counting water bought from other systems.

70 systems filed a lead service line inventory listing 0 lead lines, 145 galvanized lines that must be replaced and 46 lines of unknown material.

2 more systems are placed in San Luis Obispo County, CA by the county their records name because they have no service area map that lines up with their own records, so they are listed apart and not counted here.

Community water systems
71
People served, sum of each system's own figure
268,460
Systems with a health-based violation, last 10 years
18
Systems with one unresolved
3
Lead service lines in inventories
0

Water systems serving San Luis Obispo County

71 systems

People served is each system's own figure for its whole service area. Violation counts cover the last 10 years of EPA records.

System Serves People served Main source Health-based violations, 10 years Unresolved Lead lines
San Luis Obispo Water Department San Luis Obispo 47,788 Surface water 0 0 0
City of Paso Robles Water Division El Paso de Robles (Paso Robles) 31,176 Surface water 0 0 0
Atascadero Mutual Water Co Atascadero 30,618 Groundwater 0 0 0
City of Arroyo Grande Utilities Division Arroyo Grande 17,963 Purchased surface water 0 0 0
California Mens Colony Outside cities and towns 15,000 Surface water 0 0 0
Nipomo Comm Services Dist Nipomo and Los Berros 13,771 Purchased surface water 0 0 0
Morro Bay PW Dept - Water Division Morro Bay 13,757 Purchased surface water 0 0 0
City of Grover Beach Public Works Dept Grover Beach 12,701 Surface water 0 0 0
Pismo Beach Water Department Pismo Beach 8,036 Purchased surface water 3 0 0
Templeton CSD Templeton 8,011 Groundwater 0 0 0
Oceano Comm Services Dist. Oceano 7,601 Purchased surface water 0 0 0
Los Osos Community Services District Los Osos 7,086 Groundwater 0 0 0
Golden State Water Company - Los Osos Los Osos 5,924 Groundwater 0 0 0
Cambria Comm Services Dist Cambria 5,532 Groundwater 2 0 0
Golden State Water Company - Nipomo Nipomo 4,506 Purchased surface water 0 0 0
Atascadero State Hospital Atascadero 4,100 Groundwater 0 0 0
Woodlands Development Woodlands 3,862 Purchased surface water 0 0 0
Heritage Ranch CSD Lake Nacimiento 2,956 Surface water 15 0 0
San Miguel Community Services District San Miguel 2,600 Groundwater 0 0 0
Cayucos Beach Mutual Water Company Cayucos 2,567 Purchased surface water 0 0 0
Morro Rock Mutual Water Co Cayucos 2,181 Purchased surface water 0 0 0
Nacimiento Water Company Oak Shores 2,181 Surface water 23 0 0
Golden State Water Company-Cypress Ridge Los Berros and land outside it 2,026 Groundwater 0 0 0
Avila Beach Community Services District Avila Beach 1,630 Purchased surface water 0 0 0
San Miguelito MWC Avila Beach 1,600 Purchased surface water 2 0 0
Lopez Project San Luis Obispo and Edna 1,569 Surface water 1 0 0
Golden State Water Company - Edna Los Ranchos 1,493 Groundwater 0 0 0
Slo CWWD No. 23 - Santa Margarita Santa Margarita 1,291 Groundwater 0 0 0
Slocsa #10A - Cayucos Cayucos 1,200 Purchased surface water 0 0 0
Slo CSA No. 16 - Shandon Shandon 1,085 Purchased surface water 0 0 0
Mesa Dunes Mobile Home Estates Outside cities and towns 600 Groundwater 0 0 0
S & T Mutual Water Company Los Osos 591 Groundwater 0 0 0
Woodland Park Mutual Water Co Callender 538 Groundwater 11 0 0
Walnut Hills Mutual Water Co Templeton 486 Groundwater 0 0 0
San Simeon CSD San Simeon 462 Groundwater 3 0 0
Garden Farms C.W.D. Garden Farms 440 Groundwater 0 0 0
Los Robles Mobile Home Estates Templeton 420 Groundwater 0 0 0
Green River Mutual Water Co. Whitley Gardens 350 Groundwater 2 2 0
Santa Ysabel Ranch MWC Outside cities and towns 344 Groundwater 0 0 0
Rancho Colina Mobile Home Park Outside cities and towns 249 Groundwater 1 0 0
Irish Hills Mutual Water Co Outside cities and towns 135 Groundwater 0 0 0
Canyon Crest Mutual Benefit WC Outside cities and towns 133 Purchased surface water 0 0 0
Edna Valley Ranch East Outside cities and towns 132 Groundwater 0 0 0
Callender Grove Mutual Water Callender 126 Groundwater 0 0 0
Spanish Lakes Mutual Water Co Outside cities and towns 125 Groundwater 0 0 0
Halcyon Water System Oceano 110 Groundwater 1 2 0
Las Ventanas Ranch Outside cities and towns 108 Groundwater 0 0 0
Varian Ranch Mutual Water Outside cities and towns 105 Groundwater 0 0 0
Resthaven Mobile Home Park Outside cities and towns 99 Groundwater 20 0 0
Bassi Ranch Mutual Water Co. Outside cities and towns 85 Groundwater 0 0 0
Ken Mar Gardens Oceano 84 Groundwater 21 0 0
Baron Canyon Mutual Water Co. Outside cities and towns 81 Groundwater 0 0 0
Laguna Negra Mutual Water Co. Callender 80 Groundwater 0 0 0
Afuera De Chorro Water Company Outside cities and towns 79 Groundwater 0 0 0
Avila Valley Mutual Water Co Avila Beach 75 Purchased surface water 0 0 0
H2O, Inc Outside cities and towns 70 Groundwater 0 0 0
Monte Sereno Mutual Benefit Water Outside cities and towns 65 Groundwater 0 0 0
Country Hills Estates Outside cities and towns 60 Groundwater 12 0 0
Anza Vineyard Estates Mutual Water Co Outside cities and towns 60 Groundwater 0 0 0
Rim Rock Water Company Outside cities and towns 55 Groundwater 31 0 0
Rancho Salinas MBWC Outside cities and towns 50 Groundwater 0 0 0
Bear Valley Water Company Outside cities and towns 45 Groundwater 0 0 0
Rancho Nipomo Water Company Outside cities and towns 44 Groundwater 0 0 0
Almira Water Association Outside cities and towns 40 Groundwater 14 0 0
Terra De Oro Water Company Outside cities and towns 38 Groundwater 0 0 0
Higuera Apartments Outside cities and towns 30 Groundwater 21 2 No inventory
Mustang Springs Mutual Water Outside cities and towns 30 Groundwater 3 0 0
Ada's Lodges Outside cities and towns 25 Groundwater 0 0 0
Slo CSA No. 10 - Cayucos WTP Cayucos Not reported Surface water 0 0 0
Chorro Valley Pipeline - Slo County Outside cities and towns Not reported Purchased surface water 0 0 0
Nacimiento Water Project California Polytechnic State University Not reported Surface water 0 0 0

Systems placed by county record in San Luis Obispo County

2 systems

EPA has no service area map for these systems. They are placed by the county their records name (the counties EPA lists them serving, or the county coded in their IDs where EPA lists none), and without a map they are not counted in the figures above.

System Serves People served Main source Health-based violations, 10 years Unresolved Lead lines
Laureate Water Company County on record 700 Groundwater 0 0 0
Gran Cielo Mutual Water Company County on record 139 Groundwater 0 0 0

Cities and towns in San Luis Obispo County

28 places

Back to California

Counties come from the counties EPA lists each system serving, matched to 2024 Census counties; where EPA lists none, from the county coded in the system's ID, its service area map, or its mailing address. A county holding at least a fifth of a system's service area map is added when at least a fifth of that map lies in those counties. Towns are the ones EPA lists and the Census places such a map covers, always inside those counties. In New England, where EPA's town names a whole Town, it is not matched to the village of the same name. A system is not listed in a county holding less than a fifth of its map, or in a county or town its map reaches when the map lies mostly outside the counties EPA lists, so a page can leave out a system that serves part of the area. Methodology and limitations