Groundwater Quality Monitoring and Reporting
Growers must complete three types of monitoring and reporting related to the evaluation of groundwater and drinking water quality. These include On-Farm Domestic Wells, Primary Irrigation Wells Prior to the Start of Groundwater Quality Trends, and Groundwater Quality Trends. Growers may also be required to complete Ranch-Level Groundwater Discharge monitoring and reporting.
Helpful links and more information about each type of required monitoring is provided below. Compliance details and dates for the below listed groundwater quality monitoring and reporting requirements can be found in the Compliance Calendar.
- Groundwater Monitoring and Reporting Guidance (English | Español | 中文)
- Backflow Prevention Devices
- Nitrate in Drinking Water (English | Español | 中文)
- 1,2,3-TCP Health Information (English | Español | 中文)
Accredited Laboratories
Annual groundwater sampling must be done by an accredited laboratory. Growers are responsible for selecting a laboratory and confirming that it has the required capabilities to ensure timely compliance with Ag Order 4.0 requirements, including sampling, analysis, and reporting.
The Environmental Laboratory Accreditation Program (ELAP) maintains an interactive web map of laboratories that meet the accreditation standard. The web map is not a complete list of laboratories, or an endorsement for laboratories. A link to the web map is provided below.
Third-Party Program Members
Central Coast Water Quality Preservation, Inc. (Preservation, Inc.), an approved third-party program administrator under Ag Order 4.0, completes well monitoring on behalf of their members in good standing. Growers who are members in good standing must work with Preservation, Inc. to complete annual groundwater sampling.
On-Farm Domestic Wells
Monitoring of domestic wells is necessary to protect public health, identify domestic water wells that do not meet drinking water standards, provide timely health risk notifications, and verify well user have alternative replacement water as appropriate. Each year, growers must provide well users with a summary of laboratory analytical results with 3 business days of receiving results. Growers must also provide a summary of the most recent laboratory analytical results to any new well users within 3 business days when there is a change in population using the well. Growers must update their electronic Notice of Intent (eNOI) within 30 days of receiving results to confirm that well users have been provided with a summary of laboratory results, informed of any health risks associated with well water containing nitrate and/or 1,2,3-TCP, have an alternate source of water for domestic purposes if appropriate, and to confirm that any new well users have been provided with the most recent laboratory analytical results.
Primary Irrigation Wells Prior to Groundwater Quality Trends
Primary irrigation well monitoring must be completed annually until a groundwater quality trend monitoring and reporting workplan is approved and initiated. The objectives of sampling on-farm irrigation wells are to evaluate groundwater conditions in agricultural areas and to inform establishment of a groundwater quality trend monitoring network.
Groundwater Quality Trends
Growers must conduct groundwater quality trend monitoring and reporting, either individually or via membership in a third-party program. The objectives are to evaluate the status of groundwater quality over time, including short-term patterns and long-term trends, and to quantitatively evaluate the impact of irrigated agricultural waste dischargers to groundwater.
Third-Party Program Workplans
Central Coast Water Quality Preservation, Inc. (Preservation, Inc), an approved third-party program administrator under Ag Order 4.0, has indicated that they will submit a workplan for groundwater quality trends. The groundwater quality trend work plan for third-party programs is due September 1, 2023 for groundwater basins within Groundwater Phase 1 areas; September 1, 2025 for groundwater basins within Groundwater Phase 2 areas; September 1, 2027 for all other areas. Once third-party program workplans are approved for Groundwater Quality Trends the workplans will be available here. Stay tuned for more information!
Ranch-Level Groundwater Discharge
Based on groundwater quality data or significant and repeated exceedance of the nitrogen discharge targets or limits in the Ag Order, growers may be required to conduct ranch-level groundwater discharge monitoring and reporting. Growers that are members in good standing with a third-party alternative compliance program are exempt from this requirement.
