Boise pioneers Idaho's first Integrated Plan to manage $1.3B wastewater CIP and rate shocks

Boise pioneers Idaho's first Integrated Plan to manage $1.3B wastewater CIP and rate shocksThe city is leveraging the EPA's Integrated Planning framework to renegotiate compliance timelines for strict phosphorus and temperature limits, seeking to avoid steep rate hikes in its upcoming November permit submittal to the state.

Boise will submit an Integrated Plan, permit reapplication, and modification request to the Idaho Department of Environmental Quality in November 2026.

The strategy targets timeline flexibility for expensive tertiary filtration and cooling towers required to meet strict phosphorus and temperature limits.

Without the plan, overlapping compliance schedules for the $1.3 billion capital improvement plan would force sharp rate increases between 2027 and 2029.

Boise is the first municipality in Idaho to utilize the Integrated Planning approach, working collaboratively with the IDEQ and EPA Region 10.

The City of Boise is preparing to submit Idaho's first EPA Integrated Plan this November, a strategic move designed to manage the financial impact of its $1.3 billion, 10-year water renewal capital improvement plan (CIP). During a September 2 Public Works Commission meeting, Haley Falconer, Deputy Public Works Director for Water Renewal Services, detailed the city's approach to its upcoming Idaho Pollutant Discharge Elimination System (IPDES) permit renewal. The utility will bundle its permit reapplication and a modification request with an Integrated Plan, a framework under the Clean Water Act that allows municipalities to sequence regulatory obligations based on affordability, financial capability, and community priorities. A primary driver for the Integrated Plan is the need for timeline modifications regarding strict phosphorus and temperature limits in the Boise River. According to Falconer, the city and surrounding entities have made significant progress reducing phosphorus levels from historical highs to under 1 mg/L. However, achieving the final regulatory targets of 0.1 to 0.2 mg/L requires tertiary filtration, representing hundreds of millions of dollars in new investment. Similarly, meeting current temperature limits would necessitate the installation of expensive, energy-intensive cooling towers and chillers at the end of the pipe, which staff noted offer limited corresponding benefits to the river's ecosystem. "If we don't have an integrated plan or another mechanism to have more time for the temperature and phosphorus compliance, that requires really significant, sharp increases in our rates and funding to meet the deadlines that are in our current permit," Falconer told the commission. Without the integrated approach, overlapping compliance schedules would force a condensed construction timeline, triggering sharp rate increases between 2027 and 2029. By utilizing the Integrated Plan, Boise aims to space out its capital investments, ensuring more predictable and stable utility rates. The utility is currently evaluating funding strategies for the CIP, weighing the trade-offs of a rates-only approach versus a combination of bonds and rates. Public Works Director Steve Burgos noted that the Integrated Plan provides the Idaho Department of Environmental Quality (IDEQ) with a tool to better manage requirements. "I don't think if you talk to anyone at the DEQ, they're all that excited about chillers and cooling towers at the end of a pipe that we know are one, very expensive, huge energy requirements, and then aren't necessarily making a big difference in-stream in the river," Burgos said. While the IDEQ will not formally approve the Integrated Plan document itself, the agency will use the data to inform the permit modification and justify the schedule of compliance. Boise staff noted that EPA headquarters and Region 10 representatives have been involved in the collaborative process to help advance the framework at the state level. Following affirmation from the Public Works Commission, staff will present the strategy to the Boise City Council on October 6 before submitting the materials to the IDEQ in November. Detailed capital, funding, and rate projection impacts will be presented during the fiscal year 2028 budget cycle.