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Percolation Testing in Western Massachusetts

Excavation Plus has the capabilities and the experience to perform highly adequate percolation testing. A percolation test is used to determine the water absorption rate of the soil. When you perform a percolation (perc test) the results of it are required to properly design your own septic system or leach field. In simple terms, a percolation test will observe how quickly a known volume of water dissipates into the subsoil of a drilled hole in the ground. This is crucial for the success of a septic system.

Sandy soil will tend to absorb more water as opposed to the soil that already has a high concentration of clay or silt in it. In this case, oil is going to already be very dense which makes it difficult for water to break down and become absorbed. In Western Mass, about 90% of our soil is sandy loam. This kind of soil is most commonly used in gardening because it provides good drainage.  It amounts to roughly 40% Sand, 40% Silt, and 20% Clay.

How a Percolation Test is performed

A percolation test can range anywhere from 1-2 hours, or even take upwards of 3-6 hours depending on how new the property is that you’re going to be evaluating.

Here’s how a regular routine perc test is typically performed:

  • Find a spot to dig a test hole approximately 300mm wide and 300mm deep, this should be beneath the invert level wherever the outlet pipe starts. If your invert level is too deep then the area you’re trying to cover may have to expand to find where you can safely dig.
  • The soil needs to be completely saturated in order for the water to percolate deeply enough into the ground. The water can saturate your soil overnight, but if you notice it’s draining faster than average you may want to refill the test hole multiple times. If your water is still draining too fast, then you have your answer-which tells you that this specific area is not adequate for a home septic system.
  • If it’s the next day, we’ll fill the test hole up again and observe how quickly the water seeps away. If the water dissipates to 225mm full, we then begin timing the soil absorption to see how long it goes until the water hits 75mm. Whatever number this comes to, is the result of the amount of time that it takes us to see the water level dropping to 150mm. We’ll then divide this number by 150 to find out the Percolation Value number.
  • Depending on the day, and climate, we’d repeat this process at least 3 times per hole dug

Excavation Plus is a leading provider in the excavation industry, known for our quality work, reliability and exceptional customer service experience. Contact us today to schedule your at-home percolation testing (perc test) today!