USGS - science for a changing world

California Water Data

Basic hydrologic data collection, processing, analysis, dissemination, and archiving are major parts of the California Water Science Center program. Streamflow data, for example, are used for flood and water-supply forecasts, planning and design, river regulation, streamflow statistics, and research investigations. Much of the data are available on a near-real-time basis by satellite telemetry.

Real-Time Data

map of real-time streamflow conditions at USGS streamgage sites across California

Current California Streamflow Conditions map depicts streamflow conditions as a percentile, which is computed from the period of record for the current day of the year.

Current California Streamflow Conditions
Real-time streamflow data from automated equipment, representing the most current hydrologic conditions.

WaterWatch displays maps, graphs, and tables describing real-time, recent, and past streamflow conditions for the United States.

USGS National Water Information System (NWIS) Mapper
Shows real-time current California conditions including surface-water, groundwater, spring sites, atmospheric sites and more.

Groundwater Data

screenshop of the interactive California Active Groundwater Level Network map

California Active Groundwater Level Network contains water levels and well information from more than 20,000 wells that have been measured by the USGS or USGS cooperators at least once within the past 13 months.

NWIS: Groundwater Data for California
The Groundwater database consists of records of wells, springs, test holes, tunnels,drains, and excavations. Available information includes groundwater level data, well depth, aquifer, and more.

Groundwater Watch
Groundwater Watch groups related wells and data from active well networks reported in the USGS National Water Information System (NWIS), and provides basic statistics about the water-level data collected by USGS water science centers for Cooperative and Federal Programs, and from data supplied to us by our customers through cooperative agreements.

California Coastal Basin Aquifers
National aquifers, or principal aquifers of the United States, are defined as regionally extensive aquifers or aquifer systems that have the potential to be used as a source of potable water.

Southern California Basin Network
State and local "networks" are defined by Water Science Centers as a way to group specific collections of wells. These "networks" have a variety of criteria including political divisions, principle aquifers, cooperators, and water management districts.

Surface Water Data

map of Map of real-time streamflow compared to historical streamflow for the day of the year across California

NWIS Surface-Water Data offers hydrographs, by site, for termperature, disharge, gage height, and specific conductance.

NWIS: Surface-Water Data for California
The Surface Water database consists of records of current streamflow conditions, historical observations, daily data, peak-flow data, and field measurements from streamgages across California.

Surface-Water Watch
Maps California streamgage sites and compares real-time streamflow to historical streamflow for the day of the year.

Runoff Estimates for California
Monthly and Annual excess precipitation discharge estimates for California, including historical comparisons.

Water-Quality Data

screenshot of the GAMA water quality data map viewer

GAMA-Priority Basin Project Groundwater-Quality Results mapper displays water quality results for constituents of interest that have health- or non-health-based benchmarks, or are key tracers of groundwater age.

NWIS: Water-Quality Data for California
At selected surface-water and groundwater sites, the USGS maintains instruments that continuously record physical and chemical characteristics of the water including pH, specific conductance, temperature, dissolved oxygen, and percent dissolved-oxygen saturation. Supporting data such as air temperature and barometric pressure are also available at some sites.

Water-Quality Watch
Data from automated field equipment representing the most current hydrologic water quality conditions.

GAMA-Priority Basin Project Groundwater-Quality Results: Assessment and Trends
This interactive webmap plots water-quality data from domestic and public-supply wells sampled by the USGS for the California GAMA Priority Basin Project, and allows users to download datasets.

Site Inventory

screenshot of NWIS Mapper displaying all of the USGS well and streamgage sites located in Lake County, California

Site Inventory for California
The Site Inventory System contains and provides access to inventory information about sites at stream reaches, wells, test holes, springs, tunnels, drains, lakes, reservoirs, ponds, excavations, and water-use facilities.

Historical Water Data

map showing the location of USGS discharge and water-quality stations in Ventura County for Water Year 2003.

Excerpt from Water Resources Data California Water Year 2003 showing the location of USGS discharge and water-quality stations in Ventura County for Water Year 2003.

Historical Water Data for California
Hydrologic Data Reports for Water Years 1961 thourgh 2013, including surface and groundwater data, water quality data, and basin schematics.

USGS WaterNow

Get current-conditions for water data directly to your mobile phone or email.

Get Water Alerts

Furnished Data

Training information and guidelines for Federal Energy Regulatory Commission (FERC) licensees and other cooperating agencies for the preparation of furnished data records.

Furnished Data Guidelines

National Water Data

USGS National Water Information System (NWIS)

National Water Information System: Mapper

National Water Watch

Water Resources of the United States

California Water Science Center Highlights

Read all Highlights

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