The information in the table below is updated when open dates change or when new rainfall totals data are collected. The latest updates to the data are displayed in bold below. Data have been updated on April 26, 2017.
* Note: Wet weather percolation testing has been extended.
The Memorandum of Understanding with the State of California Regional Water Quality Control Board allows for wet weather percolation and groundwater testing between January 1 and March 1, and after having received 50% of the average rainfall.
Depth to groundwater determinations can be conducted within ten (10) calendar days following a rainfall of 0.8 inches in a 48 hour period. Sonoma County is divided into 7 geographic areas for this purpose. The amount of rainfall will be posted for each area.
Inspection requests for wet weather percolation/groundwater tests must be made by calling the County’s automated inspection request system, SELECTRON, at (707) 565-3551.