The City of Hayward is currently updating its rules and regulations on Accessory Dwelling Units (ADUs), commonly referred to as “cottages, in-law units, granny flats, or second dwelling units” in response to new State legislation (Assembly Bill 2299 and Senate Bill 1069).
Accessory dwelling units shall only be permitted as accessory uses in the Single-Family Residential (RS), Residential Nature Preservation (RNP), Medium-Density Residential (RM), Agricultural (A) zoning districts, and in the T-3 Suburban zoning district in the Mission Boulevard Corridor Form-Based Code area, where one legally constructed single-family dwelling exists as the primary structure on the parcel. b. Accessory dwellings units shall not be permitted in Planned Development (PD) zoning districts, unless otherwise constructed at the time of development as an amenity.
Design and Development Standards
All proposed accessory dwelling units shall comply with the following design and development standards: a. Quantity. On any one parcel of land, no more than one accessory dwelling unit shall be allowed regardless of the number of single-family dwellings located on the lot.
b. Unit Size. All proposed accessory dwelling units shall not exceed 50-percent of the habitable floor area of the existing single-family residence or 1,200 square-feet, whichever is less. Habitable floor area calculation shall not include garages, detached accessory structures, patio covers, porches, covered and uncovered balconies, and decks as determined by the Planning Director.
c. Maximum Number of Bedrooms. Accessory dwelling units shall not exceed a maximum of two bedrooms as sleeping quarters.
d. Attached Units. Accessory dwelling units proposed to be attached to the primary residence shall comply with the development standards set forth by the underlying zoning for the primary structure including, but not limited to, setbacks, lot coverage, height, and architectural compatibility.
e. Detached Units. Accessory dwelling units proposed to be detached from the primary residence shall comply with the minimum design and performance standards set forth by the underlying zoning district for detached, accessory and secondary structures including, but not limited to, setbacks, lot coverage, height, distance between structures, location and architectural compatibility.
f. Setbacks. Accessory dwelling units proposed to be constructed atop of existing, legal detached garages shall provide a minimum five-foot setback from the interior side and rear property lines, unless a greater setback is required pursuant to Building and Fire standards or the property is a corner lot which shall comply with the minimum street-side setback requirements. Accessory dwelling units proposed to be attached or detached shall conform to the development standards and performance standards set forth in the underlying zoning district.
g. Height Restrictions. Accessory dwelling units shall comply with the following height restrictions based on the proposed location of the unit: (1) Accessory dwelling units attached to the primary structure shall comply with the height limitations of the underlying zoning district for the principal structure. (2) Accessory dwelling units to be detached from the primary structure shall be limited to the height restrictions set forth in the underlying zoning district for detached, accessory and secondary structures. (3) Accessory dwelling units proposed to be constructed atop of legally constructed detached garages shall be subject to the review and approval of a discretionary Site Plan Review application in accordance with Section 10-1.3000 of the Hayward Municipal Code. In order to deny a Site Plan Review application, the Planning Director shall find that the accessory dwelling unit would be detrimental to the public health and safety or would introduce unreasonable privacy impacts to the immediate neighbors. In any instance, the accessory dwelling unit shall be limited to the maximum height restriction of the primary structure within the underlying zoning district
h. Independent Exterior Access. Accessory dwelling units shall provide an independent exterior access separate from the primary residence. The separate entry constructed for the accessory dwelling unit shall not face the street or the public right-of-way.