City staff propose modernized stormwater billing using impervious-area ERUs; commission to consider Oct. 14

Trevor, a city staff presenter, told the Connected City advisory board that staff are proposing a modernization of stormwater code and rate methodology that would measure impervious area with modern GIS layers and set an ERU based on the median impervious area of single‑family parcels (presented as roughly 2,800 square feet).

"We're finally, ready to kinda present our new methodology," Trevor said, describing a shift from a decades‑old footprint‑based approach toward an impervious‑area method that staff and the city's consultant, Roughtellus, say better reflects current development patterns.

Why it matters: the proposal changes how residential and multifamily properties are counted for billing. Single‑family parcels would be assigned ERUs using a median‑based binning system so the majority cluster at 1 ERU; many multifamily properties billed under master‑meter or multiple‑meter formulas would be moved into the nonresidential calculation, which divides measured impervious area by the ERU value. Staff said that for many parcels the bill will not change materially, but examples shown to the board included properties that would see significant decreases and others that could increase because previously unbilled impervious surface (private drives, parking) would be accounted for.

Staff emphasized tradeoffs and practical limits. Board members asked why the city uses billing "bins" rather than assigning fractional ERUs per parcel; staff responded that bins follow industry practice, reduce room for billing error and system limitations, and are easier to explain to customers. Staff also cautioned that GIS precision and billing‑system constraints make a fully fractional approach difficult.

Credits and maintenance agreements: Trevor said the city will reset and clarify the stormwater credit program so credits are tied to documented maintenance agreements and clearer application procedures. He said some previously awarded credits were obscure in the code and in practice — for example, when developers received credits but downstream homeowner associations were responsible for maintenance and that arrangement was not registered with the city.

Regulatory and budget context: staff linked the rate discussion to regulatory drivers, including the municipal separate storm sewer system (MS4) permit program, and to capital projects and ongoing maintenance. Trevor said the city is inventorying its storm structures and expects to use ERU revenue to support asset management and regulatory compliance.

Outreach and next steps: staff will present the rate‑setting package to the governing commission on Oct. 14. If the commission approves, the city plans to launch a public parcel viewer so customers can check how their property was measured and submit questions during a QA/QC period. Trevor said roughly 60% of accounts are expected to see no ERU increase or to decrease under the proposal.

Board members raised legal and equity questions: one member asked whether Kansas excise‑tax rules could limit billing based on parcel features rather than consumption; staff said the approach is widely applied across the state but noted they would check legal constraints. Members also urged the staff to show concrete dollar‑scale examples so commissioners and the public can see whether a change is a $1–$3 monthly difference or a larger increase for particular accounts.

The board did not take a vote on rates at this meeting. Staff asked for feedback before the Oct. 14 commission rate‑setting discussion and said they will continue outreach and technical QA/QC before any rate changes take effect.