Waste Water Department


The primary purpose of the wastewater collection system is to convey contaminated wastewater from the city's residential, commercial and industrial districts to the treatment plant. The system includes:

  • Anaerobic pretreatment facility
  • Approximately 157 miles of line ranging in size from six to 42 inches in diameter
  • Approximately 2,750 manholes
  • Five pumping stations
  • One air injection station
  • Two measuring stations


The Wastewater Collection Department is responsible for maintaining the city’s sewer main piping. They perform:

  • Inspections
  • Repairs
  • Replacement of piping
  • Root control
  • Routine cleaning

Individual homeowners are responsible for their own sewer service line, which is typically a four-inch line that runs from the home and connects to the sewer main.


For after-hours emergency sewer problems, please call 9-1-1.

Wastewater Treatment Plant Expansion

In March 2013, citizens of the City of Twin Falls approved a $38 million bond election to pay for the expansion of the wastewater treatment facility and its collection lines. The treatment plant was nearing maximum capacity and needed to be expanded to accommodate future industrial, commercial and residential growth in the City of Twin Falls and Kimberly.

The City of Twin Falls in April 2014 began the largest expansion of the wastewater treatment facility since 1965. As part of the project, contractors will construct new clarifier and aeration tanks, which will nearly double the capacity of the plant from 9.6 million gallons per day to 16 million gallons per day by December 2015.