DEQ Prepares to Finalize Discharge Permit for Lakeside Septage Treatment Plant

As a wastewater treatment plant north of Somers nears capacity, state environmental regulators are preparing to approve an expansion project and finalize a permit that would allow the upgraded facility to discharge treated residential wastewater into the ground. Constructed nearly 40 years ago to protect the water quality of Flathead Lake, the facility is operated by the Lakeside County Water and Sewer District (LCWSD) and is located between the lake’s north shore and a large oxbow in the Flathead River.

The Department of Environmental Quality (DEQ), which has the authority to issue the discharge permit and approve the upgrades, has determined that “the project lacks significant adverse effects to the human and physical environment” and is seeking public comment through Jan. 10, 2025 before issuing the final permit and allowing the project to move forward.

“Lakeside’s wastewater system is nearing capacity and in need of expansion and improved treatment,” according to DEQ’s notice announcing the draft permit. “The proposed facility meets a critical need especially as the number of nearby houses continues to increase.”

Called a Montana Ground Water Pollutant Control System discharge permit, it would authorize the district to discharge treated wastewater into the groundwater using rapid infiltration basins, which are shallow earthen basins that allow controlled infiltration of treated wastewater.

The district’s current wastewater treatment system in the Lower Valley, located on the corner of U.S. 93 and Somers Stage, uses aerated lagoons and a land-application site to dispose of treated waste, incorporating it into the soil. The proposed treatment system will replace the lagoons with a mechanical treatment plant and use drainfields to discharge treated wastewater into the underlying groundwater, in addition to using land applications during the summer months.

If approved, construction of the upgrades will begin in 2025 and are expected to cost between $26 million and $30 million. Discharge to groundwater as authorized by the permit would not begin until the second phase of construction is complete.

The project’s first phase would be funded by a combination of federal and state grants and loans, with the first phase costing approximately $13,422,047. The LCWSD will contribute $983,058. The remainder of the money will be provided through $10,421,899 in American Rescue Plan Act (ARPA) fiscal recovery funds; a $90,000 contribution from the Western Montana Conservation Commission (which has pledged a total of $1 million in support over both phases); a $1.3 million low-interest loan (2.5% for 30 years) from the DEQ’s Water Pollution Control State Revolving Fund (WPCSRF) program; and a $627,090 WPCSRF loan with principal forgiveness. The current average LCWSD monthly sewer rate is $42.53.

“DEQ is approving Lakeside Water and Sewer District to move forward with the first phase of construction for their treatment facility upgrades. Included in those upgrades is building a septage receiving facility that will eventually accept and treat septage from septic systems in the Flathead Valley,” according to DEQ’s notice.

Phase 1 construction will also include a force main to convey wastewater from the septage receiving facility to a new headworks facility at the existing Lakeside wastewater treatment plant and replacement of an existing wastewater lift station within the district’s collection system. 

On March 19, 2024, the Flathead County Commission unanimously voted to enter into an interlocal agreement with LCWSD to improve and expand wastewater treatment for the county.

As part of the agreement, the county will pave approximately 550 feet of Somers Stage Road by the end of 2026 and, according to the timeline laid out by LCWSD, the full facility will be operational by 2027.

LCWSD serves a population of 810 households and 18 business connections. The district also operates and maintains four drinking water systems.

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