Contra Costa County, California — public water systems

How does Contra Costa County compare with other California counties?

Contra Costa County has the 32nd-most active public water systems among the 201 counties listed for active California systems in EPA records; among the 72 with 3 or more systems, the median has 73. Its systems report 564,952 people served in total, the 15th-largest county figure in the state and 1.3% of the statewide total. The average system here reports serving 6,726 people, about 18% above the California average of 5,706. Population figures are what each system reports; people served by more than one system, such as a wholesaler and the town that buys from it, are counted by each.

Where does Contra Costa County's drinking water come from?

By primary water source, Contra Costa County's active systems draw on groundwater (71, 85%), purchased surface water (8, 9.5%) and surface water (5, 6%). Overall, 85% rely mainly on groundwater (including purchased groundwater) and 15% on surface water, compared with 85% and 15% across California. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Contra Costa Water District, draws primarily on surface water.

What kinds of water systems operate in Contra Costa County?

Contra Costa County's active systems break down as 39 community systems (46%), 6 non-transient non-community systems (7.1%) and 39 transient non-community systems (46%). A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. EPA lists their owner types as private (68%), local government (30%) and state government (2.4%).