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 were updated on March 19, 2018.
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.
*Due to lack of rainfall this winter, Permit Sonoma has extended the wet weather testing season beyond March 1, 2018. Geographic areas will be opened for wet weather percolation testing when each geographic area receives the total inches required of rainfall indicated in the table above. Geographic areas will be opened for wet weather groundwater testing when each geographic area receives the total inches required of rainfall indicated in the table above and receives 0.8 inches of rain in a 48 hour period.
Visit our Inspection Scheduling page to make inspection requests for wet weather percolation/groundwater tests.
View inspection codes.