County drinking water records

Contra Costa County, CA drinking water systems

41 community water systems serve Contra Costa County, CA, reporting 2,101,782 people served in all. A system that also serves other counties counts all of its customers here.

10 of them (24%) had at least one health-based violation in the last 10 years. 8 systems still have one unresolved.

29 rely mainly on groundwater and 12 on surface water, counting water bought from other systems.

37 systems filed a lead service line inventory listing 0 lead lines, 3,935 galvanized lines that must be replaced and 38 lines of unknown material.

Community water systems: 41
People served, sum of each system's own figure: 2,101,782
Systems with a health-based violation, last 10 years: 10
Systems with one unresolved: 8
Lead service lines in inventories: 0

Water systems serving Contra Costa County

41 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
East Bay MUD	Oakland, Richmond and 42 more	1,442,800	Surface water	0	0	0
Contra Costa Water District	Concord, Antioch and 15 more	198,000	Surface water	0	0	0
City of Antioch	Antioch	115,074	Surface water	0	0	0
Dublin San Ramon Services District	Dublin and San Ramon	98,776	Purchased surface water	0	0	0
Brentwood	Brentwood	64,513	Purchased surface water	0	0	0
City of Pittsburg	Pittsburg	62,500	Purchased surface water	0	0	0
Diablo Water District	Oakley	43,357	Purchased surface water	0	0	0
City of Martinez	Martinez, Alhambra Valley and 1 more	30,997	Purchased surface water	0	0	0
Golden State Water Company - Bay Point	Bay Point	23,731	Purchased surface water	0	0	0
Town of Discovery Bay	Discovery Bay	16,790	Groundwater	0	0	0
Pleasantimes Mutual Water Co	Bethel Island	644	Groundwater	0	0	0
Clayton Palms Water	Outside cities and towns	549	Purchased surface water	0	1	0
Willow Mobile Home Park	Bethel Island	481	Groundwater	0	0	0
Willow Park Marina	Outside cities and towns	380	Groundwater	20	0	0
Orwood Resort	Outside cities and towns	350	Groundwater	1	2	No inventory
Delta Mutual Water Company	Outside cities and towns	333	Groundwater	20	0	0
Riverview Water Association	Bethel Island	230	Groundwater	0	0	0
Camino Mobilehome	Byron	210	Groundwater	0	0	0
Bethel Island Estates	Bethel Island	200	Groundwater	0	0	0
Bethel Island MHC	Bethel Island	185	Groundwater	0	0	0
Oakley Mutual Water Company	Outside cities and towns	170	Groundwater	18	2	No inventory
Big Oak Mobile Home Park Water	Oakley	156	Groundwater	0	0	0
Farrar Park Property Owners	Bethel Island	140	Groundwater	0	0	0
Riverview Mobile Home Park	Pittsburg	126	Groundwater	0	0	0
Bethel Island Mutual Water Co	Bethel Island	123	Groundwater	0	0	0
Russos Mobile Park	Bethel Island	110	Groundwater	1	2	No inventory
Sandmound Mutual	Bethel Island	100	Groundwater	1	2	0
Anglers Subdivision 4	Bethel Island	99	Groundwater	0	0	0
Bella Vista Water Sys	Pittsburg	93	Groundwater	14	2	0
Marina Mobile Manor	Outside cities and towns	75	Groundwater	0	0	0
Knightsen Community Water System	Knightsen	73	Groundwater	0	0	0
Sandy Point Mobile Home Park	Outside cities and towns	67	Groundwater	1	2	0
Moraga Heights Mutual Water	Outside cities and towns	66	Groundwater	0	0	0
Doubletree Ranch Water System	Outside cities and towns	66	Groundwater	8	0	0
Angler S Ranch #3	Bethel Island	60	Groundwater	0	0	0
Dutch Slough Water Works	Outside cities and towns	49	Groundwater	0	0	0
Casa Medanos Water System	Pittsburg	45	Groundwater	0	0	0
Colonia Santa Maria	Outside cities and towns	32	Groundwater	1	2	No inventory
Wilcox Station Ranch	Outside cities and towns	31	Groundwater	0	0	0
Randall-Bold Water Treatment Plant	Oakley	1	Purchased surface water	0	0	0
CCWD/Brentwood WTP	Oakley	Not reported	Purchased surface water	0	0	0

Cities and towns in Contra Costa County

52 places

Acalanes Ridge1 system
Alamo1 system
Alhambra Valley2 systems
Antioch2 systems
Bay Point2 systems
Bayview1 system
Bethel Island11 systems
Blackhawk1 system
Brentwood1 system
Byron1 system
Camino Tassajara1 system
Castle Hill1 system
Clayton1 system
Clyde1 system
Concord1 system
Contra Costa Centre1 system
Crockett1 system
Danville1 system
Diablo1 system
Discovery Bay1 system
East Richmond Heights1 system
El Cerrito1 system
El Sobrante1 system
Hercules1 system
Kensington1 system
Knightsen1 system
Lafayette1 system
Martinez2 systems
Montalvin Manor1 system
Moraga1 system
Mountain View2 systems
North Gate1 system
North Richmond1 system
Oakley5 systems
Orinda1 system
Pacheco1 system
Pinole1 system
Pittsburg5 systems
Pleasant Hill2 systems
Port Costa1 system
Reliez Valley1 system
Richmond1 system
Rodeo1 system
Rollingwood1 system
San Miguel1 system
San Pablo1 system
San Ramon2 systems
Saranap1 system
Shell Ridge1 system
Tara Hills1 system
Vine Hill1 system
Walnut Creek2 systems

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