Sonoma County’s Revised Water Well Construction Ordinance

Written By: Admin
Published: September 1, 2015

Sonoma County has updated its water well construction standards ordinance for the first time since 1978. The revised ordinance focuses on standards for well construction, abandonment, destruction, setbacks, prohibitions, and water treatment for contaminated wells.  It also addresses permit requirements, inspections, reporting, enforcement provisions, how to handle alternate construction method requests, and more. The new version offers more detail and specific standards than the former ordinance, and reflects changes in technology for well construction that have taken place since 1978.

The revision focuses on technical aspects of well construction and destruction, steering clear of larger policy issues such as regulating groundwater use or addressing surface-groundwater interactions. The main changes from the previous ordinance center on providing specific standards for well construction and setbacks for a number of land uses and activities. Standards are provided on allowable materials and installation techniques for backflow prevention, borings, casings, construction timing, filter packs, foundations, grout materials, screens, seals, well caps, and more.

The new code maintains existing rules on setbacks for septic systems and disposal areas, but adds several new setbacks. Specifically, new wells need to be setback a minimum of 100 feet for feed yards and feed lots, and non-leaking underground hazardous storage. A 30 foot setback is required for new wells near ponds, lakes, streams and wetlands. There are some exceptions for setbacks on parcels where owners would lose access to all sources of water if complying with the setback.

The new code establishes requirements for wells that pump water used for human or animal consumption that exceed maximum contaminant levels (MCL).  It provides details on treatment, qualifications needed by contractors for installation, required monitoring, record keeping, reporting to enforcement agencies, and related treatment information.

The new rules were developed with direction from the Well Ordinance Working Group (WOWG). It was formed in 2010, and is comprised of well drillers, pump contractors, environmental health specialists, realtors, PRMD staff and others. While some individuals and groups in the county wanted to see the new ordinance establish rules on ground water use and surface-groundwater interaction, the ordinance primarily addresses technical construction standards. With the passage of the Sustainable Groundwater Management Act in 2014, a local agency will be formed by 2017 that is charged with regulating groundwater use. The ordinance does propose that well permits need to be consistent with any groundwater management plan that is adopted now or in the future. Thus rules on groundwater use will be determined later, likely after the local groundwater agency is formed.

The revised ordinance went through a few drafts and received significant public input. It went before the Board of Supervisors on July 21. The Board accepted the major provisions of the draft, but asked for some minor technical modifications. The final water well standards were adopted on the Board’s July 28th consent calendar, and took effect at the end of August.

To see the old and new ordinance, and to learn more, visit the County’s PRMD website at

Related Articles

Premium Members

To represent, protect and advance the social, economic and educational interests of the farmers and ranchers of Sonoma County.