What’s a perc test? Are we making coffee?

Over the past couple days we have been talking about septic systems, how they work, and some of the pieces and parts within a septic system.

Yesterday we talked about Mound Systems and tomorrow we will look into a Conventional In-Ground System.  Both of these do the same thing but they accomplish their task differently.  There’s an obvious question……., why would I choose to use the more expensive system for my septic?  The truth is you wouldn’t!  However, choice is not an option.  The engineer that designs your system will make that decision.

When an Engineer or a Vermont Soil Technician is hired to design a septic system the very first step in the process is to perform a “Perc Test.”  A Perc Test begins by digging a hole or two or three.  These holes that are in the area where the Septic system’s Leach Field is going will play a major role in determining what type and design of system you will have.

Several things need to be looked at:

  • Soil conditions – the various types of soil will eventually determine the nature of your septic.  There is Clay, very common throughout The Champlain Valley, loam, sand and gravel, and so on…….  Various types of soil act differently with water, or in our case sewage.
  • Water – during the perc test a measured amount of water will be used in each hole
  • Time – this is the critical part.

The engineer will pour into the hole a measured amount of water, start his stop-watch, and time exactly how long it takes for that water to Percolate Into the Earth.  (see where the name Perc Test comes from?)

Sewage needs to absorbed into the ground which will then naturally filter out all the nasty parts before that water enters the water table.  Sewage should never flow across the top of the ground nor should it go into streams, brooks, or lakes.  The earth is the best filter.  A properly built septic system insures that filtration.

The Perc Test determines HOW the sewage will filter down into the earth.  Based on the results of your Perc Test you will be required to build the appropriate system and as a result you will be protecting the environment

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