Percolation Test

One of the most important factors affecting site developability is the composition of the on-site soils. You need answers – and we aren’t afraid to get our hands dirty!

Knowing What Lies Beneath


A good plan is developed from the ground, up. Knowledge of what lies beneath the surface of a site is key in determining the limitations of potential development. Any sub-surface domestic wastewater treatment requires soil testing to determine if the design is limited by any site specific parameters. This includes the design of sewage disposal systems and stormwater treatment facilities that are regulated by both state and local agencies.

MNTM provides a range of soils testing, including: percolation tests, deep test pits, and infiltration testing.

Percolation tests are completed by hand to avoid impacting the native material. These tests are used to determine the permeability of the in-situ soils. In conjunction with percolation tests, deep test pits are completed utilizing an MNTM-approved excavator to examine the different soil horizons. These tests are performed to determine the location of any existing bedrock, water table, or an impermeable layer that may impact the site design. A percolation test, in conjunction with a deep test pit, provides all the information our engineers need for sewage disposal system design.

digging a hold to perform a soil percolation test stick in a hole for a percolation test

Similarly, infiltration tests determine whether a site is suitable for Green Infrastructure stormwater management practices with runoff reduction credits. These practices, regulated by the New York State Department of Environmental Conservation (NYSDEC), are intended to alleviate stormwater runoff concerns by getting water to infiltrate back into the ground near the development location. Knowing that your site can accommodate this water is a necessary part of stormwater design. These tests provide a picture of the on-site soils and their ability to accommodate wastewater and stormwater runoff.