Carroll County work session reviews cluster-subdivision rules after concerns about lot sizes and open space

County planning staff and commissioners spent a work session reviewing cluster-subdivision rules and a 9.2‑acre example in the Freedom planning area, with staff agreeing to draft proposed clarifications for the board and planning commission.

Chris, a county planning staff member, opened the discussion by saying, “So we're here today to talk about cluster development,” and turned the presentation over to Daphne, a county planning staff member, who walked commissioners through definitions, code history and a site example the county is processing.

The presentation reviewed three basic distinctions used in county practice: lot yield (the potential number of lots a parcel can produce), minimum lot size (the zoning‑district standard), and open space versus active open space. Daphne summarized county practice: cluster subdivisions allow reductions in individual lot sizes while ensuring the total number of dwelling units does not exceed the yield allowed for the site; open space can include forested or wetland areas, and active open space must be suitable for recreation and meet slope limits.

Why it matters: clustering changes how lots are arranged on a site but does not increase total housing units allowed by zoning, staff said. Still, commissioners raised two consistent concerns: (1) that recent practice lets developers count steep slopes, stream buffers and stormwater ponds toward required open space, producing common parcels that are not usable for recreation; and (2) that the county’s shift to a gross‑acreage yield calculation (adopted in 2022) and the frequent use of clustering are reducing individual lot area compared with older subdivisions and increasing homeowner‑association maintenance responsibilities.

Mineral Hill example: Daphne used the Mineral Hill subdivision to illustrate code application. The project is a 9.2‑acre parcel in the R‑20,000 district. Using 20,000 square feet per lot, staff computed a theoretical yield of 20 lots (9.2 acres = 400,752 sq ft; 400,752 ÷ 20,000 ≈ 20). The conventional plan submitted with the file showed 15 lots; the submitted cluster plan shows 14. Under county rules, the reduction in lot area generated a required open‑space obligation of 53,101 square feet; the developer’s plan provides about 131,990 square feet of open space, including stormwater management areas. Daphne noted the planning commission’s discussion emphasized the recorded open‑space parcel rather than counting the stormwater area as the applicant’s primary active open space, though county code does allow stormwater management areas to be included in open‑space calculations.

Stormwater and long‑term maintenance: Staff explained a long‑standing county policy to accept ownership of certain subdivision stormwater facilities rather than leave expensive pond upkeep to small HOAs. “Many, many years ago, the decision was made that we were not going to rely on HOAs to maintain these,” a county planning staff member said, noting that county ownership has simplified retrofit and NPDES (National Pollutant Discharge Elimination System) compliance. Commissioners asked about costs and tradeoffs: staff estimated that providing conventional road length and utilities instead of the cluster layout would raise the developer’s upfront cost (staff’s back‑of‑envelope estimate in the Mineral Hill example was roughly $800,000 higher for a conventional design) and would add ongoing county O&M exposure (an illustrative estimate of $5,000 per year for added roadway length). Staff also confirmed that underground stormwater systems are materially costlier to construct and often costlier to operate and maintain over time.

Code history and key policy points: Staff traced cluster provisions through the county master plan and the Freedom Community comprehensive plan and summarized code changes: open‑space criteria were refined in 1989; percolation testing for conventional lots was added in 2009; in 2014 residential cluster subdivisions were required to be on public water and sewer; and in 2022 the county moved from requiring developers to submit both a conventional plan and a cluster plan to using gross acreage to determine yield and added a lower bound on how much a lot size can be reduced (for example, an R‑20,000 minimum cannot be reduced below the equivalent of R‑10,000). Staff said that review of past projects showed conventional plans rarely produced higher yield than cluster plans and that eliminating the conventional‑plan requirement reduced time and cost for applicants.

Points of disagreement and requested clarifications: Commissioners pressed staff on several items they want clarified in code or policy: whether yield should be derived from net developable acreage (excluding steep slopes, floodplain and stream buffers) versus gross acreage; how much of required open space may consist of steep slopes or stormwater facilities (current code caps encumbered environmental features at 50% of required open space); the minimum amount and character of active open space (current rule: 10% of required open space or 1.5 acres, whichever is larger, with the planning commission allowed to modify for parcels under 10 acres); who is responsible for long‑term maintenance (HOA versus county) and whether recorded covenants can change open‑space character over time; and whether planning commission discretion and subsequent appeals to the Board of Zoning Appeals produce consistent outcomes.

Next steps: Commissioners asked staff to compile the issues discussed (definitions of open space and active open space, gross vs. net yield calculation, active‑open‑space thresholds, HOA maintenance responsibilities, stormwater ownership and O&M implications, and planning commission discretion/appeals) and return with a recommended package for the planning commission and the board. Staff confirmed an optional pre‑submittal practice has been added that allows applicants to present concept plans to the planning commission for early feedback and that the current code revisions can be changed if the board directs staff to draft amendments.

What was not decided: no formal code amendments or votes were taken at the work session; rather commissioners directed staff to draft recommended clarifications for review by the planning commission and a future public hearing. The Mineral Hill subdivision is under construction and approved at the layout discussed; staff said that once subdivision yield is recorded and final plats are recorded, remaining yield for that original parcel is considered used unless the board or state law later changes the underlying rules.

For residents and developers: staff said clustering remains an available option and that the county will return with specific code language options for commissioners to consider. Commissioners signaled they want clearer, more prescriptive language so community expectations in the master plan and the county code align with the subdivision outcomes on the ground.

Ending: Staff will prepare a summary of the issues raised and draft code options, circulate that to the board for review and return the matter to the planning commission and then to the board for public hearings if the board decides to pursue changes.