SEWAGE DEPARTMENT TRAINING PROGRAM
How to Build an At-Grade Sewage Disposal System
There are 2 types of at-grade systems:
Type A (stone on contour)
Type B (stone to level)
You will note in the above end-view diagrams that the top of the Type-A at-grade mound parallels the slope of the land surface while the type-B system's top is level. The two types are not interchangeable and each must be installed as required by the permit.
This program will only address the construction of Type-A at-grade systems.