Planning commission approves recommendation to allow some single‑family lots as small as 30,000 sq ft

Mountain Vista City Borough — The Mountain Vista City Borough Planning Commission on Nov. 3 voted to approve Resolution 25‑18, a recommendation to the assembly that would amend chapter 43.2 of the subdivision development standards to allow some lots in single‑family residential land use districts to be reduced to 30,000 square feet if the well and septic locations are shown on the plat.

“This is an ordinance that is being proposed by Assembly member Sumner,” said Alex Straub, Planning and Land Use Director. “What it does is allows an avenue for somebody to divide lots to less than 40,000 square feet ... as long as a couple of different things happen.” Straub said the key conditions would be that wells and septic systems be located on the plat and that the lots be in the single‑family residential land use district.

The measure would change the borough’s existing minimum lot size (the 40,000‑square‑foot “borough acre”). Straub and commissioners said the proposal aims to increase density modestly — creating more buildable lots to improve housing affordability and reduce per‑household infrastructure costs. Straub noted that coordinated placement of wells and septic systems can preserve the separation distances that the larger lot size originally protected.

Commissioners discussed potential downsides. Straub warned that code enforcement could be difficult if property owners do not place wells or septic systems where the plat designates them, and that placing septic systems in closer proximity could increase the potential for groundwater contamination. Straub cited Midtown Estates as an example where shared septic areas had created enforcement issues when systems were not installed as planned.

Commissioners also discussed how “detached fourplexes” have been built on 40,000‑square‑foot lots (one well and multiple septic systems), prompting prior changes to the multifamily code. Straub explained current multifamily rules: generally two dwelling units are allowed per 40,000 square feet without a multifamily permit, and higher densities require a multifamily permit; under the proposed change, the reduced‑size lots would be limited to single‑family use and would not allow new multifamily development in those zones.

The commission moved Resolution 25‑18 on a motion from Commissioner McCabe, seconded by Commissioner Collins. The chair recorded no objections and the commission approved the resolution by voice vote; the action is a recommendation to the assembly, not final adoption of an ordinance.

Commissioners and staff said the assembly and planning staff will coordinate implementation so plats show the required well and septic locations before lots are sold. Straub said Assembly member Sumner is running a concurrent land use review to help ensure that sketch plans provide the required designations.

Resolution details: Resolution 25‑18 would recommend an ordinance amending chapter 43.2, subdivision development standards, to allow lots to be reduced to 30,000 square feet in single‑family residential land use districts when wells and septic locations are pre‑designated on the plat. The transcript does not record a roll‑call tally; the chair noted no objections when the commission approved the resolution.