What is the requirement for the bottom of excavation for a standard drainfield?

The requirement for the bottom of excavation for a standard drainfield is to be level to within 1 inch per 25 feet. This standard is crucial because it helps ensure proper drainage and effective operation of the septic system. A level drainfield bottom allows for uniform distribution of effluent, preventing pooling and promoting better absorption into the surrounding soil. If the drainfield is not level within this tolerance, it could lead to uneven effluent distribution, resulting in areas that may become saturated or overloaded, thereby compromising the system's functionality and potentially leading to system failure or environmental issues. The specified measurement ensures that the installation adheres to best practices for maintaining the effectiveness and longevity of the on-site sewage facility.