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Oregon City reports early progress in sewer inflow-and-infiltration program; aims to remove 65% from system
Summary
City staff told commissioners the inflow-and-infiltration (I&I) program has inspected about 60% of targeted pipes and removed roughly 10% of problem pipe so far, and reiterated a goal to eliminate 65% of I&I from targeted basins to avoid much larger treatment-plant costs.
Oregon City staff presented the fiscal year 2024–25 annual report for the city's inflow-and-infiltration (I&I) program on June 18, saying the program has made measurable progress while keeping work within the commission-approved budget.
A public works staff member who identified himself as Evan summarized the program's approach and current status, saying the city is concentrating repairs in a small set of older basins that contribute more than half of the flow into the regional treatment plant. "The main goal that we have here is pretty straightforward. We wanna get 65% of the I&I out of those basins," Evan told the commission.
The nut of the city's strategy, staff said, is to fix leaking pipes and lateral connections in older neighborhoods rather than pursue a far more expensive option of dramatically expanding treatment-plant capacity. Staff said avoiding the worst-case treatment-plant expansion would save ratepayers tens to potentially hundreds of millions of dollars.
City staff provided these program details and early results: - Inspection and repairs: staff reported about 60% of the city’s pipes (focused on the worst-condition segments) have been inspected and about 10% of pipes have been repaired or addressed so far. - Program target: a 65% reduction in inflow and infiltration from the priority basins, chosen because they account for more than half of the flow to the treatment plant supplied by the city. - Funding and cost control: staff said the program will remain within the amounts approved in the commission's biennium budget and will not seek an immediate budget amendment. Program management is the largest single near-term budget item and covers monitoring work. - Partner funding: the city receives a one-third match from a partner identified in the presentation as Wes — for example, "we spend a million dollars. Wes gives us $333,000," Evan said — which has helped the city extend work to laterals between the property line and residences. - Methods and next steps: staff said they will continue CCTV inspections, will skip smoke testing in the coming year but resume it the year after, and are developing additional metrics (removal efficiency and capital cost offset) to report next year.
Commissioners asked about how the I&I program affected previous sewer moratoria and the amount of pipe that could become undersized if the city did not act. Evan told commissioners that earlier moratorium projects addressed the most urgent constraints and that, if the city stopped the I&I program, his estimate was that another roughly 40,000–50,000 feet of pipe could become undersized over time. He said that resolving previous moratorium constraints had required on the order of $10 million and that unmanaged deterioration could lead to far higher costs.
Commissioners and staff also discussed coordination with the pavement maintenance utility fee (PMUF). Evan said the I&I program is coordinating work with PMUF and other utility projects so the city can sequence sewer repairs and then pave streets efficiently.
Ending
City staff said they will return next year with updated efficiency and capital-offset metrics as more data accrues. Commissioners offered praise for the work and indicated continued interest in keeping the program within the approved budget while pursuing the 65% removal target.
