Boulder City Council adopted Ordinance 8666 on Jan. 9, 2025, changing lot-area, density and review standards in several residential zoning districts to encourage so‑called “missing‑middle” housing (duplexes, triplexes and similar small multi‑unit buildings). The ordinance passed on second reading by a 6‑3 roll‑call vote after more than an hour of staff briefing, council questions and a 34‑speaker public hearing that produced strongly divided testimony.

Nut graf: The ordinance, described by staff as the “Family Friendly Vibrant Neighborhoods” project, modifies rules in RMX‑1 (residential mixed 1), RM‑1, RL‑1 and RR zones to allow additional dwelling units while applying existing form‑and‑mass standards so new buildings remain similar in scale to current houses. Key provisions include a reduction in required lot area per dwelling in some zones, the ability to build duplexes on lots within specified distances of mapped bus corridors, a lowered open‑space requirement in RM‑1, and procedural changes intended to speed development of permanently affordable projects.

Staff presentation and rationale: Carl Geiler, a planner in Planning and Development Services, told council the project grew out of an earlier Zoning for Affordable Housing effort and aimed to increase missing‑middle housing while protecting neighborhood scale and historic housing stock. He said RMX‑1 contains Boulder’s oldest housing stock; about 70 percent of buildings in RMX‑1 are over 50 years old, compared with roughly 50 percent citywide. To reduce pressure on older homes, staff proposed applying existing single‑family floor‑area ratio (FAR), coverage, setback and height rules to new multi‑unit buildings so scale remains consistent.

Key technical points (per staff):
- In RMX‑1 staff proposed changing minimum lot area per dwelling unit from 6,000 sq. ft. to 2,500 sq. ft. (allowing duplexes/triplexes on appropriately sized lots while retaining single‑family scale rules).
- In RL‑1 and RR zones duplexes would be allowed on lots within 350 feet of mapped RTD bus corridors (staff estimated that change would make about 30% of lots in those zones eligible).
- In RM‑1 the open space requirement would drop from 3,000 to 2,000 sq. ft. per dwelling unit.
- Staff included a disincentive to demolition: if a building over 50 years old is demolished without permits or after a finding of probable cause that it may be eligible for landmark designation, the site would not qualify for the increased density. That provision became the most contested, and council amended it before adoption.

Public comment and council concerns: The public hearing drew 34 speakers with sharply divided views. Supporters — including housing advocates, Planning Board and members of Better Boulder — urged the ordinance as modest, incremental housing reform that would reduce car dependence and align with climate goals. Several speakers urged extending the transit buffer to 550 feet.

Opponents — including residents of University Hill, Whittier, Martin Acres and Mapleton Hill — warned the changes would accelerate investor purchases, student housing conversions, parking stress, loss of open space and loss of family‑friendly neighborhoods. Multiple speakers said the outreach survey was not statistically representative and asked for more study or for affordability conditions on new units.

Landmarks/demolition amendment: Several council members and public commenters raised the landmarking issue: under the draft, a single reviewer’s preliminary “probable cause” finding could block the density bonus even if an applicant later obtained approval to demolish a structure through the formal process. Council Member Lauren moved an amendment to remove the portion of the code that would deny the density allowance after a finding of probable cause; she said applicants who obtain formal demolition approval should still be eligible for the new density. Council adopted an amendment on that point before the final vote.

Vote and outcome: Council passed Ordinance 8666 as amended on a 6‑3 roll call (yes: Benjamin, Mayor Brockett, Mayor Pro Tem Folkerts, Schuhart, Speer, Adams; no: Council member Marquis, Wallach, Weiner). Council directed staff to prepare implementing language and to continue related work on the Boulder Valley Comprehensive Plan update and complementary programs.

Ending: The ordinance is expected to enable incremental additions of missing‑middle housing over time; staff estimated the citywide changes could allow thousands of additional dwelling units over decades if property owners take advantage of the new rules. Council members and staff repeatedly emphasized the changes are intended to be gradual and to preserve neighborhood scale while expanding housing choices.