Chapter 18.225
ACCESSORY STRUCTURES
Sections:
18.225.030 Location of accessory structures.
18.225.040 Architectural standards.
18.225.050 Agricultural structures.
18.225.060 Carports/temporary vehicle storage.
18.225.080 Accessory dwelling units.
18.225.020 General standards.
(1) General Standards. In addition to the use limitations and other regulations for the zoning district in which the accessory structure is proposed, no accessory use, building, or structure shall be allowed unless it complies with the following requirements:
(a) All accessory structures shall be incidental and subordinate to the principal use and/or structure on the property.
(b) An accessory structure shall be under the same ownership or control as the principal structure and/or use on the property.
(c) No accessory structure shall be established or constructed before the main dwelling or structure is under construction, and no accessory structure shall be occupied prior to issuance of a certificate of occupancy for the main dwelling or structure.
(d) No accessory structure shall include a residential dwelling, nor may an accessory structure be rented or otherwise used as a separate dwelling, except as provided in RCC 18.225.080.
(e) All accessory structures shall comply with any and all applicable standards and requirements of the International Building and Fire Codes.
(f) Play structures less than 15 feet in height and with a covered and/or enclosed floor area of less than 30 square feet are exempt from the general restrictions of this chapter, but must comply with all setback requirements for accessory structures.
(g) It shall be the sole responsibility of the property owner to obtain a release from the utility companies and any other entity holding rights to public utility or other easements on the property prior to any construction within those areas.
(h) Storage containers, freight containers, box cars, and similar storage equipment are prohibited. Temporary storage containers may be used during a move, but may not be present on the property for more than seven days. [Ord. 21-20 § 1 (Exh. A); Ord. 19-21 § 1 (Exh. A); Ord. 11-15 § 1 (Exh. A).]
18.225.030 Location of accessory structures.
(1) Measurements. For the purpose of this chapter, measurements shall be from the foundation of the accessory building to property line, or to foundation of the main dwelling.
(2) Accessory structures shall be located a minimum of 10 feet from the main dwelling.
(3) A minimum distance of five feet shall be maintained between accessory structures.
(4) Accessory structures may not encroach into any public utility or other easement without written permission to encroach from all parties with rights to the easement.
(5) Front Yards. All accessory structures are prohibited within any required front yard area, and no accessory structure shall extend within 10 feet of the front plane of the main dwelling.
(6) Side Setbacks. Accessory structures shall be located a minimum of five feet from the side property line, except as follows:
(a) All accessory structures located between the main structure and the side property line shall maintain the same side yard setback as required for the main structure.
(b) All accessory structures on corner lots shall maintain the minimum corner side yard setback as required for the main dwelling.
(c) Single-story accessory structures of 200 square feet or less and below 16 feet in height shall be located a minimum of one foot from the side property lines, provided no portion of the building extends over the property line and runoff is contained to the property.
(d) Accessory structures over 20 feet in height and/or including a second floor or story shall have a minimum side yard setback of 15 feet.
(7) Rear Setbacks. Accessory structures shall be located a minimum of five feet from the rear property line, except as follows:
(a) Single-story accessory structures of 200 square feet or less and below 16 feet in height shall be located a minimum of one foot from the rear property line, provided no portion of the building extends over the property line and runoff is contained to the property.
(b) Accessory structures over 20 feet in height and/or including a second floor or story shall have a minimum rear yard setback of 15 feet. [Ord. 21-20 § 1 (Exh. A); Ord. 20-31 § 1 (Exh. A); Ord. 20-21 § 1 (Exh. A); Ord. 11-15 § 1 (Exh. A).]
18.225.040 Architectural standards.
(1) Maximum Size. The maximum size of any accessory structure is two times the size of the footprint of the principal structure (house and attached garage), and the maximum total size of all accessory structure(s) on any parcel shall be limited to 10 percent of the total lot area, with any private lane as approved by Riverton City excluded from the lot area.
(2) Maximum Height.
(a) The maximum height of accessory structures shall be 20 feet. On property of at least 10,000 square feet the maximum height may be up to 25 feet.
(b) Accessory structures on property below one-third acre (14,000 square feet) in size shall be limited to one story. Unfinished storage areas under the roof trusses may be permitted, but shall not include finished walls or ceiling, or utilities such as plumbing or electrical not associated with mechanical equipment. Access to such unfinished storage areas shall not include stairs, and shall utilize ladder access only. On property of at least one-third acre and zoned R-3, R-2, RR-22, R-1, or A-5, a second story may be allowed.
(c) Height shall be measured from finished grade to the highest point on the structure.
(3) Exterior Materials and Design. Architectural standards, including general appearance, building materials, and color, shall be as follows:
(a) Accessory structures of 200 square feet or less shall be consistent in color and design with the main dwelling.
(b) Accessory structures greater than 200 square feet shall utilize only exterior building materials that are present on the main dwelling, excluding trim and nonarchitectural elements, structural materials, and prohibited materials. Colors shall be similar in tone and complementary to those used on the main dwelling. Wood or wood product siding, exposed plywood or particle board, corrugated metal, or similar materials are prohibited as exterior materials. Fiber-cement siding and aluminum or other metal siding may be substituted for vinyl siding if such siding is similar in color and appearance to the vinyl siding used on the main dwelling, as approved by the planning manager.
(c) Accessory structures greater than 1,200 square feet shall include a minimum of 20 percent of the front exterior walls, and of the street side(s) of a corner lot, in masonry such as brick or stone same type, coloring, and/or style as on the main dwelling.
(i) On property of at least one acre and zoned RR-22, R-1, or A-5, split-face or honed block may be used in place of stucco or other materials, but may not be substituted for any required brick, stone or other masonry consistent with that used on the home.
(d) For accessory structures greater than 200 square feet where exterior materials on the main dwelling consist exclusively of masonry such as brick or stone, the exterior side of the accessory structure facing the front of the lot shall be entirely masonry of the same type and style on the main dwelling. For the remaining sides, the lower one-third of each side shall be masonry as used on the front elevation, and the remaining exterior may consist of stucco and/or vinyl or fiber-cement siding that is complementary to the main dwelling in color and design. [Ord. 22-09 § 1 (Exh. A); Ord. 21-20 § 1 (Exh. A); Ord. 20-31 § 1 (Exh. A); Ord. 20-21 § 1 (Exh. A); Ord. 18-14 § 1 (Exh. A); Ord. 12-26 § 1 (Exh. A); Ord. 11-15 § 1 (Exh. A).]
18.225.050 Agricultural structures.
(1) Agricultural Structures. Accessory structures constructed on parcels of at least one-half acre and used exclusively for agricultural use, defined as exclusively for the growing of plants (greenhouses), the storage of farm animals and/or feed, as defined by ordinance, or of equipment used for commercial agricultural production on parcels of at least 20 acres. Agricultural structures shall comply with the requirements of this chapter except as follows:
(a) Agricultural structures for animals must be designed such that the primary function of the structure is the keeping of farm animals and/or feed. Structures for the growing of plants shall be designed exclusively for that use, including exterior materials.
(b) Agricultural structures above 20 feet in height shall be located a minimum of 15 feet from side and rear property lines. Agricultural structures 20 feet or below shall be located a minimum of 10 feet from property line. Agricultural structures shall, if located on a corner lot, comply with standard corner lot setback requirements.
(c) Agricultural structures may not be located within 40 feet of any residential dwelling.
(d) Maximum height of agricultural structures shall be 35 feet, with the exception of greenhouses, which may not exceed 20 feet in height.
(e) Agricultural structures may, on approval from the planning department, utilize such exterior building materials that are appropriate to the use, while complementary to the main dwelling and to the surrounding community. Greenhouses must utilize translucent or transparent material designed to allow increased sunlight as the primary exterior material, including roofing material.
(f) Agricultural structures may not include an accessory dwelling unit. Greenhouses may not include divided rooms, a second story or attic, lofts or other similar storage space. [Ord. 21-20 § 1 (Exh. A); Ord. 21-11 § 1 (Exh. A); Ord. 11-15 § 1 (Exh. A).]
18.225.060 Carports/temporary vehicle storage.
(1) Temporary carports and other such temporary vehicle covers are permitted as follows:
(a) Temporary carports may only be used for parking or/and storage of vehicles and/or trailers.
(b) Temporary carports must be less than 200 square feet, have a maximum of two enclosed sides and may not be placed on a permanent foundation.
(c) Temporary carports shall meet the same setback, height, and coverage requirements as other accessory structures. However, carports may be placed directly adjacent to the main dwelling, provided the same side yard setbacks which apply to an attached garage are met.
(d) Setbacks for temporary carports or other such structures are measured to the base of the support structure.
(e) Temporary carports must comply with any and all applicable requirements and standards of the currently adopted building and fire codes. [Ord. 21-20 § 1 (Exh. A); Ord. 19-11 § 1 (Exh. A); Ord. 12-26 § 1 (Exh. A); Ord. 11-15 § 1 (Exh. A).]
18.225.070 Swimming pools.
(1) Swimming pools, including above ground pools with capacity above 5,000 gallons, shall have a minimum setback of five feet from all property lines, and must have a minimum separation of five feet from any other structure, excluding unenclosed mechanical equipment associated with the pool or other water features, and diving boards or similar play equipment less than 36 inches in height. Setbacks for the pool are measured to water’s edge. Slides, diving, or similar structures above 36 inches shall be set back a minimum of five feet from property line, which setback shall include all elements of support for said structures.
(2) Any swimming pool, including above ground pools with capacity above 5,000 gallons, shall be completely surrounded by a non-accessible wall or fence having a height of at least six feet in which there shall be no openings larger than 36 square inches except for gates which shall be equipped with self-closing and self-latching devices. [Ord. 21-20 § 1 (Exh. A); Ord. 11-15 § 1 (Exh. A).]
18.225.080 Accessory dwelling units.
(1) Applicability. Accessory dwelling units are limited to all single-family zones, provided the lot under consideration for an accessory dwelling unit can meet all technical requirements of this chapter, and applicable building/fire codes.
(2) Methods of Creation. An accessory dwelling unit may be created through the following methods:
(a) Converting existing living area within a single-family dwelling, as an addition to an existing single-family dwelling, or within a single-family dwelling created as new construction;
(b) Converting an existing detached accessory building, as an addition to an existing accessory building; or
(c) As a newly constructed accessory building.
(3) Standards. Accessory dwelling units shall conform to the following requirements:
(a) General Requirements Applicable to All Accessory Dwelling Units.
(i) One per Lot. One accessory dwelling unit for each lot that contains a single-family dwelling.
(ii) Not a Unit of Density. Accessory dwelling units are not considered a unit of density and therefore are not included in the density calculation for residential property.
(iii) Ownership. An accessory dwelling unit shall not be sold separately or subdivided from the principal dwelling unit or lot.
(b) Owner Occupancy. The city shall only permit an accessory dwelling unit when an owner occupant lives on the property within either the principal or accessory dwelling unit. Owner occupancy shall not be required when:
(i) The owner has a bona fide, temporary absence of three years or less for activities such as military service, temporary job assignments, sabbaticals, or voluntary service (indefinite periods of absence from the dwelling shall not qualify for this exception); or
(ii) The owner is placed in a hospital, nursing home, assisted living facility or other similar facility that provides regular medical care, excluding retirement living facilities or communities.
(4) Number of Residents. The total number of residents that reside in an accessory dwelling unit may not exceed the number allowed for a “family” for the lot on which the accessory dwelling unit is found, as defined in RCC 18.05.030, Definition of terms. This chapter shall not be construed to expand or increase the number of residents who would otherwise be allowed to occupy a parcel of property under existing limitations for single-family zones.
(5) Home Occupations. Home occupations may be conducted in an accessory dwelling unit as per Chapter 18.190 RCC.
(6) Parking. An accessory dwelling unit shall require a minimum of one dedicated on-site parking space. If the property has an existing driveway, the driveway area located between the property line with an adjacent street and a legally located off-street parking area can satisfy the parking requirement if the parking requirement for the principal use complies with applicable parking standards for the appurtenant residence, and the driveway area has a space that is at least 20 feet deep by eight feet wide.
(7) Additional Requirements for Accessory Dwelling Units Located within a Single-Family Dwelling. Accessory dwelling units located within a single-family dwelling shall comply with the following standards:
(a) Any addition shall comply with the building height, yard requirements, and building coverage requirements of the underlying zoning district.
(b) Entrance Locations. Entrances to an accessory dwelling unit that are located within a single-family dwelling shall only be permitted in the following locations:
(i) An existing entrance to the single-family dwelling;
(ii) When located on a building facade that faces a corner side yard, the entrance shall be set back a minimum of 20 feet from the front building facade;
(iii) Exterior stairs on a corner lot leading to an entrance above or below the first level of the principal structure shall only be located on the rear elevation of the building;
(iv) Side entrances to an accessory dwelling unit are not considered a principal entry to the building;
(v) Exterior stairs on lots other than a corner lot, leading to an entrance above or below the first level of the principal structure, may be located on a side or rear elevation of a building;
(vi) Located on the rear facade of the dwelling.
(8) Additional Requirements for an Accessory Dwelling Unit Located in a Detached Accessory Building. An accessory dwelling unit located in a detached accessory building or as an addition to an existing accessory building shall comply with the following standards:
(a) Bulk Requirements. Accessory structures containing an ADU shall comply with all applicable general yard, square footage size and height limitations found in this chapter and any accessory building regulation found in the underlying zoning district unless otherwise regulated by this section. An accessory dwelling unit located in an accessory building shall count towards the maximum square footage of all accessory buildings as stated in this chapter. Any loft within the accessory dwelling unit of an accessory building shall not be included in calculating the footprint of the accessory dwelling unit. An accessory building that contains an accessory dwelling unit and any other permitted accessory use shall comply with all building coverage requirements of this chapter.
(b) Maximum Coverage. Shall comply with the accessory building maximum coverage requirements of the underlying zoning district.
(c) Setbacks. Shall comply with the accessory building setback requirements of the underlying zoning.
(d) Building Height. Shall comply with the accessory building height requirements of the underlying zoning.
(e) Size Requirements. An accessory building that contains an accessory dwelling unit shall be subject to the building coverage requirements for accessory buildings found in this chapter.
(f) Entrance Locations. The entrance to an accessory dwelling unit in an accessory building shall be located:
(i) Facing an alley, public street or facing the rear facade of the single-family dwelling on the same property.
(ii) Facing a side or rear property line provided the entrance is located a minimum of 10 feet from the side or rear property line.
(iii) Exterior stairs leading to an entrance shall be located a minimum of 10 feet from a side or rear property line.
(g) Balconies and Decks. Balconies and decks shall be designed as follows:
(i) Shall not exceed 80 square feet in size when located above the ground level of the building;
(ii) Shall be located a minimum of 10 feet from a side or rear yard lot line unless the applicable side or rear yard lot line is adjacent to an alley;
(iii) Rooftop decks or second-story decks are prohibited on an accessory structure used as an accessory dwelling unit.
(9) Registration Process. The owner occupant(s) seeking to establish an accessory dwelling unit shall apply for a permit to establish an accessory dwelling unit, using forms provided by the planning department. Each successive owner occupant seeking to maintain an existing, lawfully permitted accessory dwelling unit shall renew the existing permit, using forms provided by the planning department. Registration shall include a processing fee of $175.00, which will include the cost of any city inspections not associated with a building permit. The owner occupant shall comply with all applicable provisions of this title including, but not limited to:
(a) Building Permit. Obtain a building permit for construction associated with the proposed accessory dwelling unit, regardless of method of creation. No ADU permit and/or certificate of occupancy shall be issued for an accessory dwelling unit until all associated construction is complete and inspected.
(b) Statement of Owner Occupancy. An application for an accessory dwelling unit shall include documentation, using forms provided by the planning department, that demonstrates an owner occupant resides on the property.
(10) Occupancy. A certificate of occupancy/ADU permit for the ADU shall not be issued until all applicable requirements of this title have been complied with.
(a) Certificate of Occupancy. No accessory dwelling unit shall receive a certificate of occupancy/ADU permit or be occupied until the property owner completes the registration process outlined in this section. Registration is not required if the ADU is occupied by family members of the property owner.
(b) Failure to comply with the standards and requirements of this section, and any and all other applicable ordinances, standards, or regulations of the city, may result in revocation of the ADU permit and/or certificate of occupancy for the accessory dwelling unit. [Ord. 22-09 § 1 (Exh. A); Ord. 21-20 § 1 (Exh. A); Ord. 19-21 § 1 (Exh. A).]