This dataset represents polygon boundaries of all public water agencies in California including public water systems, agricultural water districts, urban water districts, Federal and State water contractors, wholesalers, retailers, and other public or private utilities that deliver water to the end user.

California Water District Boundaries
from Open Data Stackexchange:
http://opendata.stackexchange.com/questions/5157/california-water-district-boundaries
Provided in multiple GIS formats
Private Water District boundaries are areas where private contracts provide water to the district in California. This database is designed as a regions polygon database and is updated when sufficient number of changes have occured to warrant an update. Updates are determined by the needs of the local office. Separate databases are used for maintenance purposes. Boundaries are continually being updated as changes are identified by the Water Districts. The boundaries are not current for all Water http://catalog.data.gov/dataset/private-water-districts
State Water Districts
State Water Project District boundaries are areas where state contracts provide water to the district in California. This database is designed as a regions polygon database and is updated when sufficient number of changes have occured to warrant an update. Updates are determined by the needs of the local office. Separate databases are used for maintenance purposes. Boundaries are continually being updated as changes are identified by the Water Districts. The boundaries are not current for all Wa ...
that is not a typo, its the direct text http://catalog.data.gov/dataset/state-water-districts

https://web.archive.org/web/*/http://projects.atlas.ca.gov/frs/download.php/26/usbr_wat_dist_priv.zip
https://web.archive.org/web/%2a/http://projects.atlas.ca.gov/frs/download.php/245/usbr_wat_dist_state_2003_03_25.zip
gist: https://gist.github.com/pdbartsch/07277a0645fb2df9f729

Private Water District boundaries are areas where private contracts provide water to the district in California. This database is designed as a regions polygon database and is updated when sufficient number of changes have occured to warrant an update. Updates are determined by the needs of the local office. Separate databases are used for maintenance purposes. Boundaries are continually being updated as changes are identified by the Water Districts. The boundaries are not current for all Water

Polygonal representation of the California Water Service District area.

Geospatial data about Placer County, California Water Districts. Export to CAD, GIS, PDF, CSV and access via API.

San Joaquin County, CA - Water Districts

© San Joaquin County GIS

This polygon shapefile contains the boundaries for water districts in Monterey County, California. Water districts are responsible for water distribution systems that provide services the county. This layer is part of a collection of GIS data for Monterey County in California.

This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data.

The Geographic Information Systems (GIS) Unit falls under the purview of the County of Santa Cruz Information Services Department. The GIS Unit serves all County departments and external customers and provides data on land, features and people of Santa Cruz County. Santa Cruz County encompasses 4 cities and approximately 265,000 people. This coverage can be used for basic applications such as viewing, querying and map output production, or to provide a basemap to support graphical overlays and analyses of geospatial data.

This polygon shapefile depicts the boundaries of water districts in the County of San Mateo, California. A water district is a special district given the task of supplying water and sewer needs to a community. This layer is part of a collection of GIS data for San Mateo County, California.

The Geographic Information Systems (GIS) Unit falls under the purview of the County of Santa Cruz Information Services Department. The GIS Unit serves all County departments and external customers and provides data on land, features and people of Santa Cruz County. Santa Cruz County encompasses 4 cities and approximately 265,000 people. This coverage can be used for basic applications such as viewing, querying and map output production, or to provide a basemap to support graphical overlays and analyses of geospatial data.

The California Department of Water Resources (DWR) discrete (vs. continuous) water quality datasets contains DWR-collected, current and historical, chemical and physical parameters found in routine environmental, regulatory compliance monitoring, and special studies throughout the state.

Community Service Districts

Polygons representing water districts in Placer County California.

URL from idinfo/citation in CSDGM metadata.

The Sacramento County Geographic Information Systems (GIS) unit falls under the purview of the Sacramento County Department of Technology and is tasked with initiating, integrating and promoting the use of GIS Technology in the support of County business goals and objectives. This coverage can be used for basic applications, such as viewing, querying and map output production, or to provide a base map to support graphical overlays and analyses of geospatial data.

The California Department of Water Resources (DWR) has released a draft "Handbook for Water Budget Development: With or Without Models" (Water Budget Handbook), a single-volume, technical reference that systematically presents existing information on various methods and data sources for developing water budgets. The Water Budget Handbook can help in the development of water budgets for any geographic area and time period, and uses modeling and non-modeling approaches.

Community Service Districts

Alameda County Water District with district boundary. Boundaries represent voting districts (i.e., district designation for each address) and therefore may align with parcel boundaries in cases where parcels (and sometimes residences) are divided by the true city/district boundary.

This polygon shapefile represents water district boundaries in Yuba County, California. This layer is a part of a collection of data obtained from the Yuba County GIS data catalog. Last Updated 5/13/2019.