Construction of a water well begins with making a hole, using one of the three methods shown in Figure 1. Read about each method and watch videos of the most common drilling methods at WellOwner.org.
As the hole is excavated, the licensed well driller logs the depths at which water is produced. This information is used to design the well.
Figure 2 is an example of typical water well construction. The well "casing" is a metal or plastic pipe that is centered in the hole. The "well screen" is the perforated section of casing adjacent to the the water-bearing zone (aquifer). The remainder of the casing is "blank" with no perforations. Once the casing is inserted, a "filter pack" of sand and/or gravel is placed around the well screen to filter fine soils from water entering the well. The rest of the annular space, between the hole and the blank casing, is sealed with highly impervious materials to prevent contaminants from flowing through the annular space. Finally, the well is completed when the pump is placed and the wellhead features are constructed, including a concrete pad which slopes aways from the well.
To learn about principles of effective well construction, refer to Water Well Design and Construction (UC Davis with the Natural Resources Conservation Service, 2003).
Proper design and construction are key to a well's success. The well should be carefully located to minimize potential for contamination, away from septic systems and other pollutant sources. The annular space should be sealed with materials that meet statewide minimum well standards and local well ordinance requirements.
Simple preventative measures can ensure your well water stays clean:
- Establish zones of protection around your well, limiting low, medium, and high impact activities as shown in A Guide for Private Domestic Well Owners.
- Perform routine maintenance and testing: Inspect the well for cracks or other possible soruces of contamination and test water quality on a regular schedule as described in A Guide for Private Domestic Well Owners.
Properly seal abandoned wells! Abandoned wells can act as vertical pathways for pollutants to enter the groundwater. They also pose a threat to public health and safety - children, animals, or even adults can fall into abandoned wells, causing injury or death. Well Decommissioning...There's a Plan for That (video, 3:18 minutes) by the Natural Resources Conservation Service of California provides important information for all landowners to recognize and address abandoned wells - with footage from an actual well destruction in Sacramento County. If you know of, or suspect an abandoned well, contact your local enforcing agency.
A Guide for Private Domestic Well Owners, State Water Resources Control Board, March 2015
Guía para los dueños de Pozos Domésticos, Junta Estatal de Control de los Recursos de Agua de California, Marzo de 2015
Abandoned Wells, Natural Resources Conservation Service, Davis, CA, January 2010
Water Well Design and Construction, University of California, Davis with Natural Resources Conservation Service, 2003
Drinking Water From Household Wells, U.S. Environmental Protection Agency, January 2002
Water Facts 5. California Well Standards Questions and Answers DWR, June 1992. Other Water Facts related to groundwater can be viewed here.
Water Wells... and What You Should Know About Them, DWR, October 1977
Local and Regional Resources
Well Permitting Agencies are the local agencies responsible for issuing well construction, modification, and destruction permits.
Groundwater Sustainability Agencies are the local/regional agencies being formed under the 2014 Sustainable Groundwater Management Act to manage groundwater.
Regional Water Quality Control Boards are responsible for developing basin plans for their hydrologic areas, issuing waste discharge permits, taking enforcement action against violators, and monitoring water quality.
Contractors State License Board licenses water well drilling contractors under the C-57 license designation.
State Water Resources Control Board has broad regulatory authority to protect water quality.
Division of Drinking Water permits public water supply systems (serving 200 or more houses).
Department of Toxic Substance Control provides information on hazardous waste disposal and reporting spills or illegal dumping.
Department of Water Resources additional groundwater sites:
Groundwater Information Center is DWR's portal for groundwater information, groundwater management plans, water well basics, and statewide and regional reports, maps and figures.
Water Data Library provides online access to hydrologic data (groundwater level data and some groundwater quality data) for over 35,000 wells California.
California Statewide Elevation Monitoring (CASGEM) Program is an online system for accessing groundwater elevation data.
California Groundwater Association is a non-profit organization representing all segments of the groundwater industry in California.
Groundwater Resources Association of California is a professional association dedicated to resource management that protects and improves groundwater supply and quality through education and technical leadership.
U.S. EPA - Private Drinking Water Wells provides information to help homeowners care for their private wells and protect their health.
Natural Resources Conservation Service provides leadership in a partnership effort to help people conserve, maintain, and improve our natural resources and environment. Financial and technical assistance for well decommissioning may be available.
National Groundwater Association is a national non-profit organization for the groundwater industry.
The Groundwater Foundation is a national nonprofit charitable organization dedicated to educate people and inspire action to ensure sustainable, clean groundwater for future generations.