Civil Engineering and Land Surveying firm with expertise in residential and commercial industries

Pre-Percolation Test

What is a Pre-Percolation Test or Site Evaluation?

A pre-percolation test – also known as a pre-perc or site evaluation – is done to evaluate the soil conditions on-site. These tests are performed by digging soil profile holes on the lot and identifying the soil texture, structure, and consistency, along with the percent of rock and the presence of mottling1 and roots. Pre-perc testing determines the usable soils including depth which helps us establish what types of septic systems are possible for your parcel.

Adobe Associates’ wastewater department has years of experience performing these soil assessments in Sonoma, Napa, and Marin County which has led to a great working relationship with the Counties’ staff. If you are interested in learning more about this service, and the ways Adobe Associates can help, please contact our office, and ask for someone in the wastewater department.

1Mottling – A soil characteristic indicative of perched groundwater; groundwater reacts to natural iron in the soil which causes discoloration.