How many consecutive readings should be taken during a perc test?

During a percolation (perc) test, it is standard practice to take three consecutive readings to ensure accuracy and reliability. This method helps to account for any variability in the soil's absorption rate that may occur from one reading to another. By averaging these three readings, a more consistent and representative figure can be determined, which is crucial for designing a septic system that functions properly.

Taking fewer readings might not provide a comprehensive view of the soil's percolation capabilities, potentially leading to an underestimation or overestimation of its drainage quality. Therefore, three readings are generally considered the minimum needed to obtain a thorough evaluation of the soil conditions. This approach aligns with accepted engineering practices and ensures that the septic system installed will perform efficiently over its intended lifespan.