What is a Land Perk Test?

Perk tests show if soil is suitable for septic systems.
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Public sewer systems are a normal part of big city living. But, in rural areas, septic systems get rid of sewage. A land percolation test, or "perk test" for short, is one way to determine if the property can handle a septic system. It requires boring into the ground and saturating it with water to see how much sewage the untested land can absorb. Without some effective test, you could be looking at seeping sewage in the yard -- and there is no nastier image than that.

Government Inspection

Perk tests can be do-it-yourself missions, but you will need some government assistance. Contact your local health department and arrange for an inspector to be on site during testing. The health inspector verifies if the perk holes are efficient and witnesses their drainage times during saturation. He then gives a yay or nay to your septic tank installation.

Digging Holes

Dig three to six holes in the area where you want to place your septic system. The holes should be approximately 12 inches in diameter and roughly 2 feet deep. Space the holes about 30 feet from one another. Perk holes must be at least 75 feet away from any water supply, and at least 3 feet away from lot lines and easements. Don't dig within 20 feet of buildings either.



Presoak holes with 2 feet of water for at least four hours before the actual test. This creates ground conditions that would occur in a typical sewage disposal. Drive a measuring stick into the hole to mark 3, 6 and 20 inch lengths from the bottom, then fill the holes with 6 inches of water. The inspector will chart how many inches the water drains in timed intervals.


Perk vs. Soils Evaluations

Before you start digging, ask your local health department if perk testing is necessary in your state. Some, such as Michigan, Washington, and Wisconsin, require soil evaluation testing beyond the means of the homeowner. In those tests, a professional soil analyst examines the ground conditions and checks out the land characteristics to determine the property's waste absorption rate.

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