Commission backs storm-water assessment using REF method, sets $7 unit rate

The Livingston City Commission voted on Aug. 18 to authorize staff to pursue a storm-water assessment under a REF-based billing method and a proposed unit rate intended to yield roughly $500,000 per year. The measure (Resolution 5202) expresses the commission’s intent to levy the assessment for FY27 and passed by roll call (4–1).

Consultant David Twan of AE2s explained the REF approach: sample residential lots, find the median impervious area (about 2,600 square feet), and treat one REF as that typical residential unit. "A residential equivalency factor is akin to a gallon in the water and sewer world," Twan said, explaining residential accounts would be billed one REF and commercial or multi-family properties would be billed proportional to their measured impervious area.

Twan and staff illustrated sample charges: a typical residential account would be billed one REF at $7 per unit (about $84 per year), a mid-size downtown commercial parcel (roughly 6,000 sq ft impervious) would be billed multiple REF units accordingly, and very large impervious footprints (for example, a big-box store) would pay substantially more. Staff said the assessment revenue will fund one dedicated storm-water staff position, equipment and high-priority capital repairs such as conveyance improvements and separators.

Commissioners and members of the public asked how accessory dwelling units (ADUs) and development would affect the REF baseline. Staff said ADUs are treated as part of single-family counts and that the REF methodology is durable with growth but can be re-evaluated if community impervious patterns materially change. Environmental and health concerns were raised about nutrients and runoff; staff described storm separators and treatment basins as tools to mitigate water-quality impacts to the Yellowstone River.

After deliberation, commissioners moved and the resolution passed; staff will return with public-notice language, billing details, and an implementation plan for the commission to adopt.