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Ashburn VA Perc Test: Soil Absorption and the Perc Test

Perc Test

If you are building a home in area without a centralized sewage treatment system, a septic tank and local soil absorption system is a great option. This involves placing a tank underground that separates the solids and liquid waste, and discharges the liquid to an external drain field (or leach field) for treatment and disposal. There are some requirements before building out a septic system in Ashburn VA. The perc test – or percolation test – is the first and most important step.

An effective septic system relies on the gradual drainage of the septic effluent into the surrounding soil. Certain soil types and conditions are needed to support the proper disposal of treated water beyond the drain field. The perc test measures the rate that water drains through the soil to determine suitability for a drain field. On rare occasion results can be somewhat predicted based on the soil conditions of the land in Ashburn VA, but the perc test is needed – and indeed required for permitting – to establish for certain the suitability of an area.

What soil conditions are needed? The best condition for the effective treatment of wastewater is to have generally permeable soil that is unsaturated well below the depth of the septic system. The most permeable elements in soil are gravel and sand, whereas clay and large rock are less permeable. The more clay and rock, the more likely there are absorption issues. If soil can be formed in one’s hand into a cigarette shape, for example, it is likely not permeable enough for a drain field. The only way to know for sure is to conduct the perc test.

Location too is important. The soil area being tested cannot be in steeply sloped areas. Additionally, areas where water stands after heavy rains or which are prone to flooding are not suitable drain field locations in Ashburn VA. Perc testing in these areas would be inappropriate. For more information about the conditions needed to build a septic system, contact the experts at SES.

SES Company


  • Virginia Onsite Wastewater Recycling Association
  • National Onsite Wastewater Recycling Association
  • Water Environment Federation
  • Virginia Association of Counties
  • Northern Virginia Building Industry Association
  • Design Build Institute of America
  • Better Business Bureau
  • Dulles Area Realtors Association
  • Prince William Regional Chamber of Commerce

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Responsible Management Entity

SES is one of only three businesses to be licensed as a Responsible Management Entity. Loudoun County Virginia was the first in the Nation to establish requirements for an RME based on EPA recommendations. SES manages several communities required to have an RME.

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  • Licensed Conventional & Alternative Onsite Soil Evaluators (AOSE)
  • Licensed Conventional and Alternative Onsite Sewage System Operators
  • Licensed Conventional and Alternative Onsite Sewage System Installers
  • NSF Certified Septic System Inspectors
  • Virginia Class A Contractors License
  • Environmental, Monitoring Well and SDS Endorsements
  • Licensed Sewage Handler
  • Licensed Wastewater Treatment Plant Operators
  • Licensed Water System Operators

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