Perc & Mantle Testing
What is a Perc Test and Soil Mantle?
Before a septic system can be designed or approved, the County requires testing of the soil on your property.
These tests determine:
• If your soil can safely treat wastewater
• How deep the usable soil is
• How quickly water moves through the soil
Soil Mantle (Test Pit)
A soil mantle test involves digging test pits using a backhoe.
This allows the county and designer to examine the soil layers and determine how much usable soil is available.
Why this matters:
Your septic system relies on soil to naturally filter wastewater.
For a standard septic system in most Counties in our area, the requirements are:
• Minimum 6 feet of usable soil
• At least 4 feet of usable soil below the trench bottom
• Standard trench depth is approximately 24 inches
The soil test pit confirms whether your property meets these requirements.
Percolation Test (Perc Test)
A percolation test measures how quickly water moves through the soil.
This test helps determine what type of septic system will work on your property.
How the test works:
1. A test hole is dug to the expected trench depth.
2. The hole is filled with water and pre-soaked to simulate winter or wet conditions.
3. The following day, measurements are taken to see how quickly the water drains.
4. Multiple readings are taken and averaged to determine your percolation rate.
This information is required to design your septic system properly.