This test is conducted to determine the absorption rate of the soil.
The type of septic is determined by FCHD sanitarian based on percolation, topography, geology, slope and usability of the septic system. Conducted where the septic system is located
Subdivision lots - Minimum 10,000 square foot area, it is common to have a greater than a 10,000 square foot area.
10,000 sq it to be intended for the original septic system and 2 replacement systems.
A backhoe operator is hired and required to dig no less than 3 holes.
The first hole is the observation hole. This is where we find the limiting factor which is usually >50% rock or water table.
The second and third holes are the perc test holes that are 4’ above the limiting factor.
The water has 30 minutes per inch to percolate for a conventional septic system and 60 minutes per inch in an infiltrometer for a sand mound test.
The FCHD sanitarian conducts the official percolation test and records (COMAR 26):
Location of perc/observation holes
Depth of perc holes
Any other information pertinent to the solid and site characteristics of the property.