State of California
Household Water Supply Shortage Reporting System
Locally Reported Household Water Shortages for Drought Assistance

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 Department of Water Resources has provided the following statistical summaries of the data useful for statewide and local purposes. 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, data discussed in the following summaries 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. In summarizing the data, DWR has made its best effort to remove duplicate records by primarily cross-checking addresses. The summaries reflect heavy outreach conducted by local and state entities that occurred in the San Joaquin Valley during the 2012-2016 drought.

Summary of Locally Reported Household Water Shortages by County

The table below represents cumulative reports of household water shortages by county reported to the State through May 23, 2018.

Summary Table Field Definitions:

Total Shortages: Reflects the cumulative number of household water supply shortages or problems occurring from dry or failing groundwater wells or surface water supplies.

Outage: No known reported solution or follow-up made. (e.g., may be households without water using nearby facilities and/or bottled water, or vacated households not using water).

Resolved: Households that have found a solution to a reported shortage (e.g., installed a new well, lowered the well pump, groundwater levels or streamflow has returned to adequate levels, connection to a municipal water supply system, or households being served by trucked and tanked water or a connection to a nearby source). Whether resolution has been obtained is determined by the reporting county or other entity on a voluntary basis. Therefore, there may be more resolved shortages than are captured by the reporting system.

statewide
Region Total Reported
Shortages
Outage Resolved
Coastal15114
Inland23809171463
Southern20316142
Statewide259810891509
coastal region
Region Total Reported
Shortages
Outage Resolved
Alameda11
Contra Costa651
Del Norte211
Humboldt
Lake
Marin
Mendocino22
Monterey
Napa11
San Benito
San Francisco*
San Mateo11
Santa Clara
Santa Cruz
Solano211
Sonoma
Coastal Subtotal15114
inland region
Region Total Reported
Shortages
Outage Resolved
Alpine
Amador11
Butte219163
Calaveras11
Colusa99
El Dorado33
Fresno751956
Glenn291415
Kern1717
Kings83758
Lassen55
Madera307307
Mariposa1221211
Merced60582
Modoc44
Nevada44
Placer
Plumas
Sacramento22
San Joaquin26233
Shasta22
Sierra
Siskiyou
Stanislaus8282
Sutter
Tehama45441
Trinity1091
Tulare1383411342
Tuolumne835528
Yolo853
Yuba11
Inland Subtotal23809171463
southern region
Region Total Reported
Shortages
Outage Resolved
Imperial*
Inyo
Los Angeles1183
Mono11
Orange
Riverside11
San Bernardino532
San Diego761
San Luis Obispo17714235
Santa Barbara11
Ventura
Southern Subtotal20316142
* no private household water supplies

Statewide Distribution of Reported Household Water Supply Shortages

The figure below illustrates the relative statewide distribution of reported household water supply shortages.

Household Water Supply Shortages Reported to the State by Quarter

This quarterly bar chart of the reported household water shortages illustrates the variation of reported shortage numbers over time. In general, the larger number of reports in the 3rd and 4th quarters of both 2014 and 2015 relative to adjacent periods was likely in direct response to worsening groundwater and surface water conditions created by the drought beginning in 2012. The reporting frequency suggests that the shortages are seasonally driven. The frequency of reported outage dates only illustrates a degree of response to the relative severity of drought conditions.

Water supply shortages are likely created by a much broader spectrum of causes than drought alone. Other causes, including aging infrastructure like corroded wells, groundwater basin overdraft, changes to weather patterns and climate, or even surface water and groundwater management decisions, can all have a role in causing a water supply shortage. These causes likely affect specific areas in unique ways versus being common throughout the State.