A large portion of the community of Thompson Falls is currently served by private septic systems, including approximately 560 residential homes and three schools.  These systems are often not in compliance with today’s regulations and are beginning to fail. Lot size limitations prevent replacement with compliant on-site systems, and the Sanders County Sanitarian has reported substandard installations. Substandard systems are incapable of reducing nutrients and pathogens to safe levels.  This creates a significant human health and safety issue and threatens Montana’s high-quality waters.

The City’s existing sewer system also has deficiencies that need to be addressed. Some of the collection system mains date back to 1948 and are suffering from root intrusion and settling, which can result in increased infiltration and inflow and sewer backups.  Approximately 1,300 feet of 12-inch asbestos cement (AC) pipe along the banks of the Clark Fork River needs replacement and approximately 600 ft of additional pipe that frequently plugs needs replacement.  Additionally, the Main Lift Station also does not have permanent back up power and poses a potential for system backups and overflows.

The PER evaluates alternatives to connect the unsewered area of the City to the central sewer system, as well as address deficiencies in the current wastewater system.  If nothing is done to address the deficiencies in the wastewater system, there will continue to be adverse impacts on the environment and human health.