Perc Test in NC - What is it?

What is a Perc Test?
The Perc Test (or Percolation Test) is a method to measure a soils ability to absorb a known volume of water over time.  This method was commonly used to evaluate a site’s ability to be suitable for a septic drain field in North Carolina in the early 1980’s.  This testing method is no longer utilized in North Carolina for several reasons.  Other factors in soil physical properties were not considered in the early evaluations and design of onsite wastewater systems.  The main overlooked feature is the depth to the seasonal ground water level.  Many sites in the coast have soils with a high sand content and have moderate to rapid permeability.  These soils are dry and can transmit water for most of the calendar year; however, during the wet season many of these soils have a high soil wetness condition that inhibits water flow and creates direct exposure of untreated wastewater into the ground water and potentially creates surfacing.

Modern method of evaluation
The Perc test has evolved in North Carolina and South Carolina into a method called the “Soil Evaluation”.  This method includes field observation of the soil physical properties that include Soil Color, Structure, Texture, Landscape Position and other horizontal setbacks to environmentally sensitive areas, water supply features and other wastewater fields.  The current method has been in practice under current regulation since the early 1990’s and has functioned to create better functioning wastewater dispersal fields that adequately treats wastewater all year. 

Why Do I Need a Perc Test (Soil Evaluation)?
Many people purchase land and sell land.  An independent evaluation from a licensed soil scientist can be beneficial to both buyer and seller.  Often a seller can have better ability to sell a property if an evaluation has been conducted that indicates the site is suitable for onsite wastewater.  Everyone who may purchase property should do all proper investigation to limit liability and understand the capability of the subject property.  Independent evaluations by consultants do not require the level of site preparation that an official county permit evaluation involves and can often be expiated much faster. 
Are there any other tests needed for my land?
Other evaluations can include but are not limited to 404 Wetlands, Coastal Wetlands, Foundation Testing, and Phase I Evaluations.  These evaluations are standard on most all properties; however, in rural areas where public wastewater is not always available, one of the most significant evaluations is the “soil evaluation.”  It is important to be sure that your subject property can handle the wastewater flow for your project goals.  Many times, people do not perform this test until after the transaction, then find out their land does not have the available space or soils that are considered suitable for an onsite wastewater system.  It’s always best to include this evaluation in the due diligence period to ensure that the site has the potential to achieve the goals you have in mind.  
As always at LMG, we are committed to assisting landowners utilize their land to its highest potential. 
And as the premiere Environmental Consulting Firm in Wilmington North Carolina and the surrounding area,
we always conduct our tasks in a safe and professional manner.
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