Drought & Conservation

Harvest Sources

In California, water systems serving one (1) to 15 households are regulated at the county level. Counties vary in their practices, but rarely do counties collect data regularly from these systems. Even where data is collected, it is entirely voluntary. A review of well permit information suggests there are over 1 million such water systems in California. In early 2014, a cross-agency Work Group created an easily accessible reporting system to get more systematic data on which parts of the state had households at risk of water supply shortages. The initial motivation for local water supply systems to report shortage information was to obtain statewide drought assistance. The reporting system receives ongoing reports of shortages from local, state, federal and non-governmental organizations, and tracks their status to resolution. While several counties have developed their own tracking mechanisms, this data is manually entered into the reporting system. The cross-agency team, led by DWR, seeks to verify and update the data submitted. However, due to the volunteer nature of the reporting and limitations on reporting agencies, collected data are undoubtedly under-representative of all shortages to have occurred. In addition, reports are received from multiple sources and there are occasionally errors and omissions that can create duplicate entries, non-household water supply reporting, and under-reporting. For example, missing information or no data for a given county does not necessarily mean that there are no household water shortages in the county, rather only that none have been reported to the State.

Updated Oct 7, 2026

Harvest Sources

DWR continuous groundwater level measurements contains continuous time-series data from automated recorders at sites operated by the Department of Water Resources. Readings are taken at 15-minute to one-hour intervals. Some of the readings are relayed to the California Data Exchange Center. However, most of the monitoring sites are visited once every month or two, when readings are off-loaded from data recorders, then finalized and published. Wells monitored for this dataset are located within Butte, Colusa, Glenn, Mendocino, Modoc, Sacramento, San Joaquin, Shasta, Siskiyou, Solano, Sutter, Tehama, Yolo, and Yuba Counties. Water-level measurements are the principal source of information about changes in groundwater storage and movement in a basin, and how these are affected by various forms of recharge (e.g., precipitation, seepage from streams, irrigation return) and discharge (e.g., seepage to streams, groundwater pumping). Water-level monitoring involves "continuous" or periodic measurements. Continuous monitoring makes use of automatic water-level sensing and recording instruments that are programmed to make scheduled measurements in wells. This provides a high-resolution record of water-level fluctuations. Resulting hydrographs can accurately identify the effects of various stresses on the aquifer system and provide measurements of maximum and minimum water levels in aquifers. Continuous monitoring may be the best technique to use for monitoring fluctuations in groundwater levels during droughts and other critical periods when hydraulic stresses may change at relatively rapid rates, or when real-time data are needed for making water management decisions [see usgs reference](https://ca.water.usgs.gov/sustainable-groundwater-management/groundwater-levels-california.html).

Updated Oct 7, 2026

California State Water Resources Control Board

This list includes detail information as reported annually under each water right as stored in the State Water Resources Control Board's "Electronic Water Rights Information Management System" (EWRIMS) database. All water right holders are required to submit an online report of water diversion and use detailing their annual water use (even if no water was diverted or used during the period). The report is the record of actual water diversion and use made under the water right permit. The information is required pursuant to Title 23, Sections 847 and 925, of the California Code of Regulations. Information provided in the report may be used by the State Water Board to evaluate compliance with permit terms and conditions. The annual report contains information about the water diversion and use, measuring devices, water storage, statement of compliance, project status (for permits), special uses, rates of diversion, water supply contracts, water conservation, water transfers, conjunctive use, etc. Each row correspond with a unique annual report-water right id combination and its associated data. The list include basic summary information about the Water Right record, such as the type and status, the location of the Points of Diversion, the amount of water allowed (Face Value), and summary data associated with the electronic Water Right record. This file is in flat file format and may not include all information associated to a water right such all uses and seasons or the amounts reported used for every month. The information associated with crop irrigation is not included in this list but is included on a separate file. Other information may be available in the associated flat files for each category. Examples of annual reports templates are provided as supporting information.

Updated Sep 30, 2026

California State Water Resources Control Board

The following datasets are used for the Water Rights Demand Analysis project and are formatted to be used in the calculations. The State Water Resources Control Board Division of Water Rights (Division) has developed a methodology to standardize and improve the accuracy of water diversion and use data that is used to determine water availability and inform water management and regulatory decisions. The Water Rights Demand Data Analysis Methodology (Methodology https://www.waterboards.ca.gov/drought/drought_tools_methods/demandanalysis.html ) is a series of data pre-processing steps, R Scripts, and data processing modules that identify and help address data quality issues related to both the self-reported water diversion and use data from water right holders or their agents and the Division of Water Rights electronic water rights data.

Updated Sep 30, 2026

California State Water Resources Control Board

Monthly reports of water use and conservation activities by urban retail water suppliers, which are generally defined as agencies serving over 3,000 service connections or deliveries 3,000 acre-feet of water annually for municipal purposes. The most recent reporting period generally lags by about 2 months, due to the reporting deadline and the necessary subsequent dataset preparation. The full dataset that spans June 2014 to the most recent reporting period is the Per-Supplier Water Supply and Demand resource, which is an updated version of the dataset previously released on the Water Board's [Water Conservation Portal](https://www.waterboards.ca.gov/water_issues/programs/conservation_portal/conservation_reporting.html). Other datasets include the per-water-system supply and demand, representing a subset of the SAFER Clearinghouse dataset, and the conservation actions datasets. See the documentation PDF for data dictionaries and an explanation of the data flag methodology.

Updated Sep 30, 2026