Where accessory residential units are allowed, they are subject to Site Design Review under chapter 18.5.2, and shall meet all of the following requirements.
A. R-1 Zone. Accessory residential units in the R-1 zone shall meet the following requirements.
1. One accessory residential unit is allowed per lot, and the maximum number of dwelling units shall not exceed two per lot.
2. Accessory residential units are not subject to the density or minimum lot area requirements of the zone, except that accessory residential units shall be counted in the density of developments created under the Performance Standards Option in chapter 18.3.9.
3. The maximum gross habitable floor area (GHFA) of the accessory residential unit shall not exceed 50 percent of the GHFA of the primary residence on the lot, and shall not exceed 1,000 square feet GHFA.
4. The proposal shall conform to the overall maximum lot coverage and setback requirements of the underlying zone.
5. Additional parking shall be provided in conformance with the off-street parking provisions for single-family dwellings in section 18.4.3.040, except that parking spaces, turn-arounds, and driveways are exempt from the paving requirements in subsection 18.4.3.080.E.1.
B. RR Zone. In addition to the standards in subsection 18.2.3.040.A, accessory residential units in the RR zone shall meet the following requirements.
1. If the accessory residential unit is not part of the primary dwelling, all construction and land disturbance associated with the accessory residential unit shall occur on lands with less than 25 percent slope.
2. The lot on which the accessory residential unit is located shall have access to an improved city street, paved to a minimum of 20 feet in width, with curbs, gutters, and sidewalks.
3. No on-street parking credits shall be allowed for accessory residential units.
4. If located in the Wildfire zone, the accessory residential unit shall have a residential sprinkler system installed.
C. R-2 and R-3 Zones. Accessory residential units in the R-2 and R-3 zones shall meet the standards in subsection 18.2.3.040.A, except that the maximum gross habitable floor area (GHFA) of the accessory residential structure shall not exceed 50 percent of the GHFA of the primary residence on the lot, and shall not exceed 500 square feet GHFA.