The purpose of these code provisions for accessory dwelling units (ADUs) is to: (1) provide homeowners with flexibility in establishing separate living quarters within or adjacent to their homes for the purpose of caring for elderly parents, providing housing for their children, companionship, security, or other purposes; (2) increase the supply of affordable housing units within the community; (3) provide for a range of choices of housing in the city and provision of additional dwelling units, thereby increasing densities with minimal cost and disruption to existing neighborhoods; and (4) ensure that the development of accessory dwelling units does not cause unanticipated impacts on the character or stability of single-family neighborhoods.
(1) Development Standards for Accessory Dwelling Units. An ADU shall comply with the following standards:
(a) Configuration. An ADU may be located either within, attached to, or detached from the primary structure.
(b) Density. Only one ADU may be created in conjunction with each single-family residence in the R1 and Town Center zoning districts.
(d) Maximum Unit Size. The gross floor area, calculated from finished wall to finished wall, of an existing structure, an addition, or a new detached structure converted to or constructed for the purpose of creating an ADU shall not exceed 40 percent of the gross floor area of the primary single-family structure, not including garage and/or detached accessory buildings, or 800 square feet (whichever is less).
(e) Minimum Unit Size. The gross floor area of an ADU shall not be less than 300 square feet, even if this exceeds the maximum requirement in subsection
(1)(d) of this section, or as otherwise established by the requirements of the city's adopted building code.
(f) Setbacks and Lot Coverage. Additions to existing structures, or the construction of new detached structures, associated with the establishment of an ADU shall not encroach into required setbacks as prescribed in the underlying zone. The applicable setbacks shall be the same as those prescribed for the primary structure, not those prescribed for detached accessory structures. An ADU shall not be included in the maximum lot coverage calculation.
(g) Scale and Visual Subordination. The ADU shall be visually subordinate to the primary unit. Specifically, new detached structures, or additions to existing structures, created for the purpose of establishing an ADU, shall not comprise more than 40 percent of the total front elevation of visible structure, including the combined ADU and primary unit. This standard does not apply for internal conversions of existing structures.
(h) Parking. One additional on-site parking space is required in conjunction with the establishment of an ADU. The two required off-street parking spaces provided for the primary residence shall be maintained.
(i) Design and Appearance. An ADU, either attached or detached, shall be consistent in design and appearance with the primary structure. Specifically, the roof pitch, siding materials, color and window treatment of the ADU shall be similar to the primary structure.
(j) Construction Standards. The applicant must apply for a building permit for an accessory dwelling unit. An ADU shall comply with applicable building, fire, health, and safety codes. Addressing of the ADU shall be assigned by the community development department. An ADU cannot be occupied until a certificate of occupancy is issued by the building department. The design and construction of the ADU shall conform to all applicable standards in the building, plumbing, electrical, mechanical, fire, health, and any other applicable codes.
(2) Detached accessory dwelling units require Type I site plan approval; however, no application fee is required.
(3) An accessory dwelling unit shall connect to public sewer and water. A home or lot not connected to public sewer and water, which adds an accessory dwelling unit, shall connect to public sewer and water.
(4) Impact fees for ADUs shall be calculated at 35 percent of the single-family rate.
(Ord. 1167 § 1, 1995; Ord. 1421 § 1, 2001; Ord. 1632 § 1 (Exh. A), 2009; Ord. 1654 § 1 (Exh. A), 2010; Ord. 1740 § 1 (Exh. A), 2013; Ord. 1793 § 1 (Exh. A), 2016; Ord. 1886 § 1 (Exh. A), 2019; Ord. 1929 § 1 (Exh. A §§ 3 – 6), 2020)