What does a percolation/soil profile test determine?

A percolation test, also known as a perc test, is primarily used to determine the size of the absorption field needed for septic systems. This test evaluates the rate at which water is absorbed into the soil, which is crucial for assessing the soil’s suitability to treat wastewater from a septic system. The results of a perc test help to inform how large the absorption area must be to adequately handle the effluent from the system, ensuring that the wastewater can be properly filtered and absorbed without causing contamination or failure of the system.

The test involves digging a specific sized hole in the ground, filling it with water, and measuring how quickly the water level drops over a certain period. The rate of absorption is critical information when designing a septic system, as it directly influences the design and layout of the absorption field capacity.

Understanding this aspect of soil behavior is essential for environmental health, as inadequate sizing can lead to system failures, causing environmental and public health issues.