Three Oaks Engineering

Septic System Perc Test Soil Mapping

Perc Tests

Onsite septic systems are utilized to treat and dispose of domestic wastewater when municipal sewer is not available. Every septic system requires an appropriately sized area of suitable soil for effective wastewater treatment.

A “perc test” is the soil investigation that determines if suitable soil exists on a parcel. Property owners and potential buyers are encouraged to have a perc test completed to obtain the essential soil and septic system information needed when buying or selling any parcel of land.

Our Soil Consultants have completed perc tests and other soil evaluations throughout North Carolina, including Durham County, Orange County, Wake County, Johnston County, and Chatham County.  We are experienced in locating usable soil areas, obtaining required permits, and siting septic systems.

​Related Services:


  • Septic System "Perc Test" and Permitting
  • Soil Mapping
  • Septic System Design and Layout
  • Groundwater Mounding Analysis
  • Lateral flow Analysis
  • Hydraulic Conductivity (Infiltration) Testing
  • Water Balance Reports
  • Wetland and Stream Delineations

"Perc" Tests for Septic Systems