Napa County, California — public water systems

How does Napa County compare with other California counties?

Napa County has the 13th-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 161,950 people served in total, the 33rd-largest county figure in the state and 0.4% of the statewide total. The average system here reports serving 861 people, well below 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 Napa County's drinking water come from?

By primary water source, Napa County's active systems draw on groundwater (169, 90%), surface water (15, 8%) and purchased surface water (4, 2.1%). Overall, 90% rely mainly on groundwater (including purchased groundwater) and 10% 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, City of Napa, draws primarily on surface water.

What kinds of water systems operate in Napa County?

Napa County's active systems break down as 28 community systems (15%), 64 non-transient non-community systems (34%) and 96 transient non-community systems (51%). 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 (89%), local government (8%), state government (2.1%) and federal government (0.5%).