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Permit Sonoma › › Eng and Constr › Wet Weather Percolation Groundwater Testing
Well and Septic Systems

2024 Season - Wet Weather Groundwater Determinations & Percolation Testing: Partially Open

Published: April 15, 2024

rain gauge

Groundwater determinations and percolation testing are necessary for onsite wastewater treatment systems (OWTS) in unincorporated Sonoma County.

  • Groundwater determinations have reopened in the Guerneville testing area, closed in all other testing areas.
  • Percolation testing is open in all testing areas.

(Testing areas: Cloverdale, Guerneville, Healdsburg, Petaluma, Santa Rosa, Sebastopol, and Sonoma)

Rainfall totals data and/or testing dates are valid as of April 15, 2024.

More Information: Wet Weather Groundwater Determinations & Percolation Testing