Public Works and Stantec present measured-ERU option for stormwater fee; committee seeks outreach and credit program before rollout

Public Works stormwater staff and consultant Stantec briefed the Environmental Matters Committee on Feb. 19 on a proposed change to the city’s stormwater fee structure for nonresidential parcels. The proposal would eliminate tiered billing for commercial and institutional parcels and instead bill nonresidential properties by measured impervious area, using an Equivalent Residential Unit (ERU) of 2,500 square feet.

Mike Rosberg, stormwater program manager for Public Works, said the city issued a fiscal-year-24 watershed report as required by code and that staff have parcel-level impervious-area data. Consultant Dave (David) Feider of Stantec explained the fee mechanics: single-family homes would remain charged 1 ERU and multifamily units would remain at 0.5 ERU per unit under the current practice, while nonresidential parcels would be billed by the number of ERUs derived from their measured impervious square footage.

Stantec’s modeling, holding all other assumptions constant, showed the measured-ERU approach would increase watershed-fund revenue from about $900,000 to about $1.0 million in the current-fee context — a roughly $100,000 uplift — because the tier caps currently limit charges on some large impervious parcels. The consultant also provided a distribution of estimated impacts: many parcels would see little or no change; about 243 nonresidential parcels would see bill reductions, roughly 524 parcels would see small increases (commonly $0–$200 per quarter), and a small number of very large parcels could face substantial increases (some > $2,000 per quarter) if unmitigated.

Committee members asked questions about outreach, legal and technical readiness, and credit programs. Anne Rotor, stormwater engineer in Public Works, emphasized that affected property owners should be given clear notice, a method to appeal impervious-area measurements, and access to a credit program that reduces fees in exchange for implementing on-site best management practices (BMPs). She and other committee members drew on Baltimore City and county examples: credits generally require applications and, for large credits, professional certification that BMPs are installed and maintained.

Members also discussed timing for a rollout. Staff said GIS and parcel data are in place and a change could be implemented in the next fiscal year if the committee and council direct it, but members urged that a credit program and outreach plan be established before billing changes take effect. Members suggested phasing, proactive outreach to the largest-impacted parcels, and linking credits/incentives to stormwater reduction and urban-forestry strategies (for example, converting parking areas to tree wells and green infrastructure).

Committee members also asked staff to run fee scenarios that include the potential urban-forestry program costs Adams described earlier; staff said they would incorporate those costs into upcoming fiscal-year scenarios. Staff agreed to provide more detailed parcel-level impact tables, a draft credit program framework and a proposed outreach and appeals timeline to the committee at a future meeting.