The design flow for MSTS serving existing dwellings is determined by the following calculation in conjunction with part 7080.1850:
the total flow from the ten highest flow dwellings + (total flow from the remaining dwellings * 0.45)
For new housing developments to be served by a common SSTS, the developer must determine and restrict the total number of bedrooms for the development. Proposed dwellings are determined to be Classification I dwellings for flow determination purposes unless different classifications are approved by the local unit of government. The determined classification system must be used in conjunction with the flow calculation method in subpart 1. If the ultimate development of phased or segmented growth meets or exceeds the thresholds in part 7081.0040, subpart 1, item B, the initial system or systems and all subsequent systems require a state disposal system permit.
If construction of additional dwellings or bedrooms, installation of additional water-using devices, or other factors likely to increase the flow volumes can be reasonably anticipated, the MSTS must be designed to accommodate the additional capacity as determined by the local unit of government.
Minn. R. agency 167, ch. 7081, pt. 7081.0120
Statutory Authority: MS s 115.03; 115.55