The first step in installing or replacing a septic system is to have a septic field design completed by a Registered Wastewater Professional.
In British Columbia, the majority of septic systems are designed and installed by Registered Onsite Wastewater Practitioners. The septic field design is just as it sounds. It is a comprehensive document that details the size of the system, the type of treatment proposed, the location of the various components, as well as the many other details that accompany a good septic design.
A septic field design must be preceded by investigative work to determine the requirements of the property and the intended use. During the course of gathering all the necessary site information, the septic field designer can determine the most suitable location for the various components of the system. On a large lot with a number of siting options, it is helpful to consider sight lines from the home, and high use areas outside the home. Nothing worse than seeing an unsightly plastic lid every time you look out your picture window, or having to move a deck or sidewalk thanks to a poorly sited tank.
Done properly, the preliminary site work will give the designer information such as how quickly the soil drains, whether there are underlying soil conditions that may prevent or hinder drainage, and also will consider distances, or setbacks as we call them to critical features on the property. These setbacks can be horizontal, such as wells, water courses, steep slopes and vertical to features such as high seasonal water table, hard pan and glaciated soil layers(dense and impermeable).