Current Percolation/Groundwater Conditions - Permit & Resource Management Department

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Wet Weather Percolation/Groundwater Testing

Maps showing area boundaries and, groundwater table determinations
groundwater test guidelines are available.

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Area	Total Required	Total to Date	Groundwater	Percolation
Petaluma	12.5"	9.20"	Closed	Closed
Sonoma	15"	8.69"	Closed	Closed
Santa Rosa	15"	11.30"	Closed	Closed
Sebastopol	17.5"	14.80"	Closed	Closed
Guerneville	25"	20.19"	Closed	Closed
Healdsburg	20"	14.35"	Closed	Closed
Cloverdale	20"	15.96"	Closed	Closed

This information updated when open dates change – date is shown at bottom of this page. 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.

Although every effort is made to provide complete and accurate information on this website, users are advised to contact appropriate PRMD staff before making project decisions. This may involve contacting more than one section within PRMD (e.g. Building, Plan Check, Zoning, Well & Septic, etc.), since each section implements specific codes or ordinances which may affect your project.