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"	18.78"*	CLOSED	OPEN until April 20
Sonoma	15"	17.29"*	CLOSED	OPEN until April 20
Santa Rosa	15"	22.11"*	CLOSED	OPEN until April 20
Sebastopol	17.5"	26.85"*	CLOSED	OPEN until April 20
Guerneville	25"	34.31"*	CLOSED	OPEN until April 20
Healdsburg	20"	25.24"*	CLOSED	OPEN until April 20
Cloverdale	20"	29.68"*	CLOSED	OPEN until April 20

* Please note, the wet weather soil percolation and ground water determination season is now open for the listed areas. The wet weather soil percolation and groundwater determination testing is open for non-standard systems. The wet weather soil percolation and groundwater determination testing is open for standard systems on a case by case basis. The ground water determination testing closed on April 2, 2012. The wet weather soil percolation testing will close on April 20, 2012. We will continue to monitor the rainfall and soil conditions to potentially open the testing for the remaining two areas and/or extended the testing period. The information is 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.