California Water Watch (Linked Application)
California Water Watch (CWW) brings together data from a variety of sources to allow viewers to obtain a quick snapshot of California's water conditions at tha statewide scale or a scale of their local watershed. The website allows viewers to query information on precipitation, temperature, reservoirs, streamflow, groundwater, snowpack, soil moisture, and vegetation conditions, and to display user-defined boundary areas of interest, including HUC-8 watersheds, counties, water agencies, groundwater sustainability agencies, and drinking water providers. Watersheds are a fundamental spatial area for assessing local water conditions. CWW maps display information at the scale of Hydrologic Unit Code-8 (HUC-8) watersheds. HUC boundaries are defined by the U.S. Geological Survey; a HUC-8 watershed is considered a subbasin of a major river basin. California includes all or part of 140 HUC-8 watersheds. Precipitation and temperature values provided on the website are for HUC-8 watersheds selected by the viewer. This website only provides data; it does not interpret or characterize the data for regulatory, administrative, or financial assistance purposes. Viewers seeking information about regulatory or financial assistance programs related to hydrologic conditions should consult the website of the specific program to determine the conditions that program uses to determine regulatory requirements or eligibility. California Water Watch does not constitute a separate authoritative dataset; it provides access to and visualization of information from multiple authoritative source datasets. Information about these datasets, including source and access details, is available on the [About the Data](https://cww.water.ca.gov/about-the-data) page. **Update Frequency:** Varies by indicator and underlying source. Many CWW products are updated daily or more frequently; groundwater information is generally updated semiannually (spring/fall), consistent with SGMA reporting cycles. **Spatial Coverage:** California statewide. Information may be displayed or queried by HUC-8 watershed, county, water agency, groundwater sustainability agency, drinking water provider, and other geographic units, depending on the indicator and underlying source data. **Temporal Coverage:** Ongoing. California Water Watch integrates current and near-real-time observations from multiple water and climate data sources. Periods of record vary by data source and indicator; historical observations and climatological averages are included for comparison and context.
Data files
Supporting files
| Data title and description | Access data | File details | Last updated |
|---|---|---|---|
CWW Home / Application Primary landing page for California Water Watch. Provides current local and statewide water conditions using dynamically updated information from multiple data sources. Users can search by address or map location to explore precipitation, temperature, reservoirs, streamflow, groundwater, snowpack, soil moisture, and vegetation conditions. [Launch California Water Watch](https://cww.water.ca.gov/) | Download | HTML (WEB APPLICATION) | 09/30/26 |
Map Interface California Water Watch map viewer for selecting a location and exploring precipitation, temperature, reservoirs, snowpack, groundwater, streamflow, soil moisture, and vegetation conditions. | Download | HTML (WEB APPLICATION) | 09/30/26 |
About the Data Describes the data sources used by California Water Watch, including data format, frequency of updates, available statistical analyses, and source-specific information for precipitation and temperature, reservoirs, streamflow, groundwater, snowpack, soil moisture, and vegetation conditions. | Download | HTML | 09/30/26 |
Forecasting Provides graphics and links to weather and longer-range outlooks beyond current hydrologic conditions, including National Weather Service forecast products and experimental forecasting products supported by DWR. | Download | HTML (WEB APPLICATION) | 09/30/26 |
Site Info / Disclaimer Provides information about the purpose and use of California Water Watch, including how viewers can query information on maps and display user-defined boundary areas of interest. It also provides disclaimers concerning interpretation and use of the data and mapped boundaries. | Download | HTML | 09/30/26 |
Hydrology Update Report Regular summary of current weather conditions in California that supplements the data on the California Water Watch website. The report includes information on precipitation, temperature, reservoirs, snowpack, streamflow, groundwater, and related forecast information. | Download | PDF | 09/30/26 |
Yearly Summary (prior water years) Provides a water-year yearly summary of statewide precipitation, reservoir storage, and snowpack, including values relative to historical averages. | Download | HTML (WEB APPLICATION) | 09/30/26 |