10.708 Residential Density.
The minimum and maximum number of dwelling units permitted shall be determined by multiplying the project’s gross acreage, less non-development areas (NDAs), by the zoning district minimum and maximum density factor, consistent with subsections (1), (2), and (3) of this section.
(1) Definitions. When used in this chapter in reference to the residential density calculations, the following terms shall have the meaning as herein assigned:
(a) Dwelling Unit (DU). The number of dwelling units permitted. Minimum and maximum density is rounded to the nearest whole number (up for numbers 0.5 and greater, and down for numbers less than 0.5).
(b) Gross Area (GA). The total area of all lots within a project’s boundaries. If the project is adjacent to an existing public street, the boundaries of the project shall be extended to the centerline of the right-of-way, and that area within the right-of-way included in the gross area, as illustrated in Section 10.012.
(c) Non-Development Areas (NDAs). Those areas that may be removed from the density calculation, at the discretion of the developer.
(i) Reserve Acreage. As allowed in Section 10.202(7).
(ii) Natural Unbuildable Areas. Those natural areas unsuitable for building (e.g., wetlands, slopes over 30 percent, and creeks (from top-of-bank to top-of-bank)). Does not include manmade nonbuildable areas such as setbacks.
(iii) Oversize Residential Lots. Lots with an existing house and yard, that exceed the maximum lot area as allowed in Section 10.702(3)(a).
(iv) Stormwater detention and treatment facilities, including access to the facility.
(v) Developer tracts as allowed in Section 10.202(6).
(d) Minimum Density Factor (min. df). Minimum number of dwelling units per gross acre allowed for the zoning district, as defined in Section 10.709.
(e) Maximum Density Factor (max. df.). Maximum number of dwelling units per gross acre allowed for the zoning district, as defined in Section 10.709.
(2) Calculations. The minimum and maximum number of dwelling units permitted shall be determined by multiplying the project’s gross area, less NDAs (at the option of the developer), by the zoning district minimum and maximum density factor.
(a) Examples:
(i) Minimum Density Calculation. The project site lies within the SFR-4 district and contains six gross acres (GA). The developer intends to retain two acres of reserved acreage (NDA). The minimum number of dwelling units and/or lots permitted is calculated as follows:
(GA-NDA) min. df. = (6-2)2.5 = 10
(ii) Maximum Density Calculation. The project site contains six gross acres (GA) of land within the SFR-4 district. The developer intends to retain two acres of reserved acreage (NDA). The maximum number of dwelling units permitted is calculated as follows:
(GA-NDA) max. df. = (6-2)4 = 16
(3) General Exceptions to Residential Density Calculations.
(a) Multiple-Family Dwelling Units in Commercial Zoning Districts. The minimum density factor shall be the same as the MFR-30 zoning district, found in Section 10.709; there is no maximum density restriction.
(b) Mixed-Use Buildings. For mixed-use buildings as defined herein, in commercial zoning districts there shall be no minimum or maximum number of dwelling units required. In the Neighborhood Commercial (C-N) zoning district, dwelling units must be located in a mixed-use building.
(c) Congregate Living Facilities. For units in a congregate living facility that do not contain full kitchen or cooking facilities, each unit may be counted as 0.7 of a dwelling unit for purposes of calculating density. The living unit shall be counted as a full dwelling unit for purposes of calculating the parking requirement.
(d) Parcels Under One (1) Gross Acre. For parcels under one gross acre in size, the minimum density may be reduced by one unit without applying for an Exception.
(e) Middle Housing. Duplexes up to two units on a legal unit of land in the SFR-2 zone are permitted regardless of maximum density. Duplexes, triplexes, quadplexes, and townhomes in the SFR-4, SFR-6, and SFR-10 zones up to four units and cottage clusters up to eight units on a legal unit of land are permitted regardless of maximum density.