Carroll County discusses cluster subdivision rules, citing Mineral Hill example and calls to clarify open-space rules

Staff members and county commissioners used a Sept. 1 work session to review Carroll County’s cluster‑subdivision rules and a specific example project, Mineral Hill, and to flag several areas for code clarification and possible changes.

Staff member Chris opened the session by framing clustering as an established tool that groups homes to preserve open land: “Cluster development is not a new concept,” he said, noting the county has allowed cluster subdivisions since 1965. Planning staff member Daphne then reviewed definitions and code provisions in the Freedom Community Comprehensive Plan and the county subdivision regulations.

Why it matters: Commissioners said current practice departs from what many residents expect from the county master plan and from older local precedent. Several asked staff to return recommended code edits that would make open‑space requirements, the method for calculating allowable lot yield, and the limits on minimum lot sizes clearer and harder to reinterpret over time.

Key facts and the Mineral Hill example - Mineral Hill is a 9.2‑acre parcel in the Freedom District zoned R‑20,000. Staff showed the arithmetic used in the example: 9.2 acres ≈ 400,752 square feet; divided by the R‑20,000 district minimum (20,000 sq ft) produces a theoretical maximum yield of 20 lots. - The applicant’s conventional plan laid out 15 lots; the submitted cluster plan showed 14 lots. Under current county rules the cluster subdivision did not increase the permitted number of dwelling units. - Because the developer reduced some individual lot sizes below the R‑20,000 minimum, the code required the developer to provide a calculated amount of common open space equal to the aggregate lot‑size reduction. For Mineral Hill staff calculated a required open‑space amount of 53,101 square feet…