Water Wells

Dry Weather Well Testing

Properties with water wells may need dry weather well testing. It is required in the following situations:

• When building a new or replacement dwelling in Class 4 Areas (PDF 409 KB), or
• When building an accessory dwelling unit (ADU) in Class 3 or 4 Areas (PDF 409 KB), or
• As required by Permit Sonoma staff to comply with Health and Safety Conditions.

See Dry Weather Testing to learn more.

Resources for Maintaining Wells

• WLS-011 Disinfecting Wells

Permit Sonoma is providing this message to remind well customers of certain requirements and expectations regarding well construction permits and well pump test permits.

1. Well Construction Applications and Permits
   Well Construction Applications must comply with the provisions of the Sonoma County Code, Chapter 25B. Applications must clearly identify the proposed work in the application form and on the site plan. An application may propose one primary water well location and up to four alternative locations. A Permit may authorize only one water well to be completed and multiple wells to be destroyed. Multiple non-water wells (e.g., geotechnical borings) can be installed under one Permit.
   
   The final well location and work completed must be identified by submitting a revised site plan before final approval of the Permit. All dry holes must be properly destroyed and shown on the revised site plan.
   
   The applicant for a Permit must be a well drilling contractor with a valid California C-57 license. The C-57 contractor who applied for and received the Permit is responsible for the work performed under the issued Permit, including any subcontracted work. Permits are not transferable.
2. Water Conservation Requirements
   Water well permits (except public water wells and injection wells) require the implementation of water conservation and best management practices.
3. Metering and Monitoring
   All water wells require the installation of a meter and reporting of water use, except for residential wells serving a single parcel with a total groundwater use of 2.0 acre-feet or less of water per year.  All water wells require monitoring and reporting of depth to groundwater, except for wells with cumulative groundwater use of 5.0 acre-feet or less water per year.
4. Discretionary Public Trust Review
   Wells, where groundwater use will be increasing, and total groundwater use of the parcel will be greater than 2 acre feet per year (651,703 gallons per year), and the well is located within the Public Trust Review Area (PTRA) will require discretionary public trust review. The PTRA is delineated in Sonoma County Code Section 25B-14 and viewable through this Well Ordinance Online Map.

Wells that are defective or no longer being used must be properly destroyed to ensure the groundwater aquifers are protected and preserved for current and future uses. Well abandonment and destruction work must comply with the provisions of Sonoma County Code Section 25B-7.

Emergency well construction applications and permits must comply with Sonoma County Code Section 25B-5(d) provisions. The application must state “Emergency Well Permit” or “Out of Water.” An applicant for a water well may request expedited permit processing where the proposed well drilling is immediately necessary to protect human life, health, and safety or property due to a sudden, unforeseen impairment in the quantity or quality of water available. Requests must be accompanied by verifiable evidence demonstrating the necessity of the proposed well.

All inspection requests must be made by calling our automated phone service, Selectron, at (707) 565-3551 or by using our online inspection resources. For Permit Sonoma to provide better customer service and manage the variety of inspection requests received, please submit inspection requests at least 24 hours before commencing work. Inspection requests may be made up to five (5) days in advance.