When properly operating, a private sewage system safely treats wastewater by storing sludge and solids in the septic tank and by treating and dispersing wastewater in a soil absorption field. However, a failing system can harm the environment by discharging sewage to the surface, to a lake or stream, or to groundwater. Your private sewage system may not show any apparent signs of failure and yet be failing.
The types of failing private sewage systems are divided into three categories:
- Category 1 systems are those which fail by discharging sewage to surface water, groundwater, drain tiles, bedrock or zones of seasonally saturated soils. These are considered the most serious types of failure, and are given highest priority for grant assistance.
- Category 2 systems are those which fail by discharging sewage to the surface of the ground. This type of failing system is eligible for a grant but has a lower priority for funding than Category 1 systems.
- Category 3 systems are those which fail by causing the backup of sewage into the structure served. This type of failing system is not eligible for grant assistance.