Missoula adopts 20-year water and wastewater master plans outlining $655m in capital needs

Missoula adopts 20-year water and wastewater master plans outlining $655m in capital needsThe Montana city’s newly approved 2025 facility plans project significant rate increases to fund extensive collection and distribution upgrades, while looming nutrient limits on the Clark Fork River could add up to $67 million in treatment costs.

City Council unanimously approved the 2025 Water and Wastewater Facility Plans, forecasting $335 million and $320 million in respective 20-year capital spending.

Water system priorities include replacing 2.5 miles of pipe annually to combat leakage tied to 12,000 galvanized service lines, plus SCADA upgrades and a new storage reservoir.

Wastewater upgrades will target structural corrosion at the Resource Recovery Facility and establish a 1.3% annual sewer main replacement rate.

Pending Total Maximum Daily Load (TMDL) updates by the state could require up to $67 million in alternative effluent management solutions, such as constructed wetlands.

To fund the improvements, wastewater rates are projected to rise 9% annually until 2029, while water rates will see 4% to 5% annual increases.

The Missoula City Council unanimously approved resolutions adopting the 2025 Water and Wastewater Facility Plans on August 31, 2026. Prepared by Jacobs Engineering and Morrison-Maierle, the plans outline a combined $655 million in capital improvement projects (CIP) over a 20-year horizon to address population growth, aging infrastructure, and shifting regulatory mandates. The $335 million water CIP targets systemic leakage issues primarily caused by 12,000 galvanized customer service lines. The utility plans to replace at least 2.5 miles of distribution pipe annually at an estimated cost of $8 million to $10 million per year. Additional near-term water investments include a $10 million to $12 million north zone storage reservoir and a $5 million system-wide replacement of obsolete SCADA programmable logic controllers across 83 locations. On the wastewater side, the $320 million CIP addresses both collection and treatment deficiencies. The collection system, noted in the plan as falling behind industry standards for replacement, will target a 1.3% annual rehabilitation rate, equating to 4.3 miles of pipe per year. At the Resource Recovery Facility (RRF), immediate condition-related needs include repairing structural corrosion in the headworks building, installing new odor control systems, and replacing blowers and centrifuges. Growth-related expansions will eventually require a new UV system, an additional bioreactor, and a new outfall pipe to the river. A major cost variable for the wastewater utility is an anticipated update to the Clark Fork River Total Maximum Daily Load (TMDL) by the Montana Department of Environmental Quality, expected by 2028. Depending on the stringency of future nutrient limits, the city evaluated several effluent management alternatives. While baseline RRF improvements would cost $14 million to $18 million, stricter limits could force the city to implement remote site land application or constructed wetlands, pushing costs as high as $65 million to $67 million. To finance the sweeping upgrades, a new utility rate study is currently underway, with recommendations expected for 2028. Preliminary projections indicate water rates will need to increase by 4% to 5% annually. Wastewater customers face steeper hikes, projected at 9% annually until 2029, scaling down to 8% through fiscal year 2032 and settling at 6% annual increases through 2044.