Chapter 18.31 DEVELOPMENT STANDARDS – ACCESSORY DWELLING UNITS AND COTTAGE HOUSING DEVELOPMENTS

It is the purpose of this chapter to implement the policy provisions of the housing element of the city’s comprehensive plan by eliminating any unnecessary or onerous barriers to the location of accessory dwelling units in single-family residential zones and to provide for a more diverse and affordable housing stock while maintaining neighborhood quality. It is also the purpose of this chapter to provide owners of single-family dwelling units with a means of obtaining rental income, companionship, security, and services through tenants in either the accessory dwelling unit or the principal dwelling unit. (Ord. 2008-397 § 4; Ord. 2000-216 § 3).

18.31.020 Definitions.

A. “Accessory dwelling units” shall have the meaning stated in NMC 18.06.183.

B. “Property owner” shall mean the owner of the property as indicated by documents recorded with the King County department of records and elections. (Ord. 2008-397 § 4; Ord. 2000-216 § 3).

18.31.030 Accessory dwelling unit regulations.

One accessory dwelling unit shall be permitted as subordinate to a single-family dwelling unit if the accessory dwelling unit meets the following requirements:

A. Owner Occupancy. Either the principal dwelling unit or the accessory dwelling unit must be occupied by an owner of the property, or an immediate family member of the property owner. A principal or accessory dwelling unit is occupied by the property owner or the owner’s immediate family member if the principal or accessory dwelling unit is the owner or family member’s legal residence, and the owner or family member actually resides in the principal or accessory dwelling unit for more than six months each year. “Immediate family member” shall mean the owner’s spouse, child, stepchild, parent, mother-in-law, father-in-law, grandparent, grandchild, or sibling.

B. Subdivision. The accessory dwelling unit, or the land on which the accessory dwelling unit is located, shall not be subdivided or otherwise segregated in ownership from the principal dwelling unit, or the land on which the principal dwelling unit is located.

C. New or Existing Development. The accessory dwelling unit shall be allowed in either an existing or a newly constructed single-family residence.

D. Size and Scale. The accessory dwelling unit shall be a minimum of 300 square feet and not more than 1,000 square feet in size, and shall not exceed 40 percent of the total square footage of the primary dwelling unit and the accessory dwelling unit, excluding any garage area; provided, that if the accessory dwelling unit is located completely on a single floor, the director of community development may allow the accessory dwelling unit to exceed these square footage requirements to the extent necessary to efficiently use all floor area.

E. Location. The accessory dwelling unit may be added to or included within the same structure as the principal dwelling unit, or the accessory dwelling unit may be located in a detached structure.

F. Entrances. The primary entrance to the accessory dwelling unit shall be located in such a manner that the entrance is unobtrusive from the same view of the building that encompasses the primary entrance to the principal dwelling unit.

G. Architectural Design. An addition to an existing structure or a newly constructed detached structure created for the purpose of developing an accessory dwelling unit shall be architecturally designed to be consistent with the roof pitch, siding, and windows of the principal dwelling unit.

H. Parking. No fewer than three off-street parking spaces shall be provided for each primary dwelling unit with an accessory dwelling unit.

I. Home Occupations. A site may not contain both an accessory dwelling unit and a Type II home occupation or a home industry, as defined in Chapter 18.30 NMC.

J. Compliance with Applicable Codes. The accessory dwelling unit shall comply with all standards as adopted by the city, and any other applicable codes or regulations, except as provided in this chapter. Except as provided in this chapter, the accessory dwelling unit shall comply with all zoning code provisions for single-family residences, including height and setbacks, and the accessory dwelling unit shall be included as part of the impervious surface and floor area limitations for a building site. (Ord. 2008-397 § 4; Ord. 2005-311 § 1; Ord. 2000-225 § 1; Ord. 2000-216 § 3).

18.31.040 Accessory dwelling unit permit.

A. Application. The property owner shall apply to the department of community development for an accessory dwelling unit permit, on an application form determined by the department, and shall pay an application fee in the amount established by resolution. The application shall include an affidavit signed by the property owner stating that the owner, or an immediate family member of the owner, will occupy the principal dwelling unit or the accessory dwelling unit for more than six months each year.

B. Inspection. After receipt of a complete application and prior to final approval of an accessory dwelling unit permit, the city shall inspect the property to confirm that the accessory dwelling unit meets all requirements of this chapter and other applicable codes or regulations.

C. Recording Requirements. Prior to approval of the accessory dwelling unit permit, the applicant shall record with the King County department of records and elections a document that identifies the address and legal description of the property, and states that the owner or a member of the owner’s immediate family resides in either the principal dwelling unit or the accessory dwelling unit for more than six months each year, that the owner will notify any prospective purchaser of the property of the limitations and requirements of this chapter, and that the permit will be revoked if the accessory dwelling unit at any time fails to meet the requirements of this chapter. The document shall run with the land and bind all current and future property owners, and the owner’s assigns, beneficiaries and heirs.

D. Permit. If the director of community development determines that the requirements of this chapter and all other applicable codes and regulations are met, then the accessory dwelling unit permit shall be issued.

E. Enforcement. The city shall retain the right to inspect the accessory dwelling unit, at any reasonable time and with reasonable advance notice, for compliance with this chapter. (Ord. 2008-397 § 4; Ord. 2000-216 § 3).

18.31.050 Pre-existing accessory dwelling units.

A. An accessory dwelling unit that existed on the effective date of the ordinance codified in this chapter may be legally established, and may continue to be used as an accessory dwelling unit, if: (1) the property owner files an application for and obtains an accessory dwelling unit permit; and (2)(a) either files an affidavit that the accessory dwelling unit meets the minimum requirements as determined by the director, notwithstanding any other provision of this chapter, or (b) requests that the accessory dwelling unit be inspected by the city to ensure the minimum requirements are met, as determined by the director, notwithstanding any other provision of this chapter. The application fee required in NMC 18.31.040 shall be waived for an application for an accessory dwelling unit that existed on the effective date of the ordinance codified in this chapter, if the application is filed within 18 months of the effective date of the ordinance codified in this chapter.

B. The owner of an accessory dwelling unit that existed on the effective date of the ordinance codified in this chapter, and that does not meet the requirements of subsection (A) of this section, must cease to use the structure or portion of a structure as an accessory dwelling unit. (Ord. 2008-397 § 4; Ord. 2000-225 § 2; Ord. 2000-216 § 3).

18.31.060 Utility hook-up.

The city shall not require that an accessory dwelling unit have a separate connection to any utility service facilities; provided, that the owner shall comply with any rules or regulations of the utility service provider regarding the connection of an accessory dwelling unit to the service provider’s facilities. (Ord. 2008-397 § 4; Ord. 2000-216 § 3).

18.31.070 Termination by property owner.

The termination or elimination of an accessory dwelling unit may be accomplished by the property owner recording with the King County department of records and elections a certificate that states that the accessory dwelling unit no longer exists on the property. The owner shall provide a copy of the certificate to the department of community development. (Ord. 2008-397 § 4; Ord. 2000-216 § 3).

18.31.080 Variances.

Except as provided otherwise in NMC 18.31.030(D), any variance from the requirements of this chapter shall require approval pursuant to Chapter 18.44 NMC and NMC Title 19. (Ord. 2008-397 § 4; Ord. 2000-216 § 3).

18.31.090 Violations.

Any person violating any provision of this chapter shall be subject to an enforcement action, a civil penalty, or permit revocation, under NMC Title 4 or Chapter 18.50 NMC, or any other remedy provided for by this code or by state law. (Ord. 2008-397 § 4; Ord. 2000-216 § 3).

Article II. Cottage Housing Development

18.31.100 Voluntary provision and intent.

These standards are intended to address the changing composition of households and provide for alternative housing choices. The provisions of this chapter are available as alternatives to typical single-family and multi-family developments where allowed pursuant to Chapter 18.08 NMC, Permitted Uses. (Ord. 2008-397 § 4).

18.31.110 Accessory dwellings.

Accessory dwelling units shall not be permitted in cottage housing developments. (Ord. 2008-397 § 4).

18.31.120 Carriage units.

Carriage units shall be allowed in cottage housing developments. Carriage units may account for no more than 25 percent of the total number of cottage units. (Ord. 2008-397 § 4).

18.31.130 Dispersion.

No cottage housing development shall be closer than 1,000 feet, measured from the property edge, to another cottage housing development. (Ord. 2008-397 § 4).

18.31.140 Density.

A. Cottage housing developments shall contain a minimum of four cottages arranged on at least two sides of a common open space or configuration as otherwise approved by the director, with a maximum of 16 cottages per development.

B. On a lot to be used for a cottage housing development, existing detached single-family residential structures, which may be nonconforming with respect to the standards of this section, shall be permitted to remain, but the extent of the nonconformity may not be increased. Such nonconforming dwelling units shall be included in the maximum permitted cottage density.

C. Cottage housing developments shall be allowed a density not to exceed 2.0 times the base density allowed in the underlying zone. (Ord. 2008-397 § 4).

18.31.150 Height limit and roof pitch.

A. The height limit permitted for structures in cottage housing developments shall be 18 feet.

B. The ridge of pitched roofs with a minimum slope of six to twelve (6:12) may extend up to 28 feet. The ridge of pitched roofs with a minimum slope of four to twelve (4:12) may extend up to 23 feet. All parts of the roof above 18 feet shall be pitched. (Ord. 2008-397 § 4).

18.31.160 Lot coverage and floor area.

A. The maximum lot coverage permitted for buildings in cottage housing developments shall not exceed 50 percent and the maximum total lot coverage shall not exceed 60 percent.

B. No more than 30 percent of the cottages may exceed a floor area of 1,300 square feet and no cottage shall be more than 1,500 square feet.

C. The maximum main floor area is 1,000 square feet.

D. The total floor area of each cottage shall not exceed either 1.5 times the area of the main level or the maximum floor area allowed in subsection (B) of this section, whichever is less.

E. Enclosed space in a cottage located either above the main level and more than 12 feet above finished grade, or below the main level, shall be limited to no more than 50 percent of the enclosed space of the main level. This restriction applies regardless of whether a floor is proposed in the enclosed space, but shall not apply to attic or crawl spaces (less than six feet in height).

F. Areas that do not count as total floor area are:

1. Unheated storage space located under the main floor of the cottage.

2. Attached roofed porches.

3. Detached garages or carports.

4. Attached garages less than 250 square feet.

5. Spaces with the ceiling height of six feet or less measured to the exterior walls, such as a second floor area under the slope of a roof.

G. The total square foot area of a cottage dwelling unit may not be increased. A note shall be placed on the title to the property for the purpose of notifying future property owners that any increase in the total square footage of a cottage is prohibited for the life of the cottage or duration of city cottage regulations. (Ord. 2008-397 § 4).

18.31.170 Setbacks.

A. Front Setback. The front setback for cottage housing developments shall be not less than 10 feet.

B. Rear Setback. The minimum rear setback for a cottage housing development shall be not less than 10 feet. If abutting an alley the rear setback may be reduced to not less than five feet.

C. Side Setbacks. The minimum required side setback for a cottage housing development shall be not less than five feet. When there is a principal entrance along a side facade, the side setback shall be no less than 10 feet along that side for the length of the pedestrian route. This 10-foot side setback shall apply only to a height of eight feet above the access route.

D. Interior Separation for Cottage Housing Developments. There shall be a minimum separation of six feet between principal structures. When there is a principal entrance on an interior facade of either or both of the facing facades, the minimum separation shall be 10 feet. (Ord. 2020-613 § 10; Ord. 2008-397 § 4).

18.31.180 Required open space.

A. Quantity of Open Space. A minimum of 400 square feet per unit of landscaped open space is required. This quantity shall be allotted as follows:

1. A minimum of 200 square feet per unit shall be private usable open space (setbacks and common open space shall not be counted as private open space); and

2. A minimum of 150 square feet per dwelling unit shall be provided as common open space. (Setbacks and private open space shall not be counted as common open space.) Common open space shall contain at least one of the following amenities:

a. Play area;

b. Sitting and reflection area;

c. Gardening area; or

d. Other similar in nature amenity approved by the city.

B. Critical areas and buffers shall not be counted as open space.

C. Each house shall abut its private open space. A fence or hedge not to exceed three feet may separate private open space from common open space.

D. Cottages shall be oriented around and have their main entry from the common open space.

E. Private usable open space shall be provided in one contiguous area with a minimum area of 200 square feet. No horizontal dimension of the open space shall be less than 10 feet, and shall be oriented toward the common open space as much as possible.

F. Required common open space shall be centrally located and in one contiguous area. Each cottage shall abut the common open space, and the common open space shall have cottages abutting at least two sides.

G. The minimum horizontal dimension for common open space shall be 10 feet on all sides. (Ord. 2008-397 § 4).

18.31.190 Development standards.

A. Each cottage unit shall have a covered porch or entry of at least 60 square feet with a minimum dimension of six feet on any side.

B. Secondary entrances facing a street or sidewalk shall have a minimum of a five-foot by five-foot porch.

C. Separation of Identical Building Elevations. Units of identical elevation types must be separated by at least two different elevations. This will result in at least three different elevation plans per cluster. No two adjacent structures shall be built with the same building size or orientation (reverse elevations do not count as different building elevations), facade, materials, or colors.

D. Variety in Building Design. A variety of building elements and treatments of cottages and accessory structures must be incorporated. Structures must include articulation, change in materials or texture, windows, or other architectural feature. No blank walls are allowed.

E. Five-foot-wide pedestrian pathways (sidewalks) must be included to provide for movement of residents and guests from rights-of-way, parking areas, common open space, and homes.

F. Community buildings are encouraged. (Ord. 2008-397 § 4).

18.31.200 Parking.

A. Parking shall be:

1. Located on the cottage housing development property.

2. Located in clusters of not more than five adjoining spaces and parking clusters separated by a distance of at least 20 feet.

3. Screened from public streets and adjacent residential uses by landscaping or architectural screening.

4. Parking is allowed between or adjacent to structures only when it is located toward the rear of the principal structure and is served by an alley or private driveway.

5. Off-street parking requirements are as follows:

a. Units under 700 square feet: one space per unit;

b. Units between 700 and 1,000 square feet: 1.5 spaces per unit; and

c. Units over 1,000 square feet: two spaces per unit.

One additional space will be provided for every four cottages. At least one parking stall per dwelling will be enclosed or covered.

6. Access to parking shall be from the alley when property abuts a platted alley improved to the city’s public works standards or when the director determines that alley access is feasible and desirable to mitigate parking access impacts.

7. Not located in the front yard.

B. Covered parking areas should be located so their visual presence is minimized, and associated noise or other impacts do not intrude into public spaces. These areas should also maintain the single-family character along public streets.

C. For shared detached garages, the design of the structure must be similar and compatible to that of the dwelling units within the development.

D. Shared detached garage structures shall be reserved for the parking of vehicles owned by the residents of the development. Storage of items which preclude the use of the parking spaces for vehicles is prohibited.

E. The design of carports must include rooflines similar and compatible to that of the dwelling units within the development. (Ord. 2008-397 § 4).

18.31.210 Screening requirements.

A. Boundaries between cottage dwellings and neighboring properties shall be screened with landscaping to reduce the appearance of bulk or intrusion onto adjacent properties, or otherwise treated (i.e., through setbacks or architectural techniques) to meet the intent of this section.

B. Common waste and other storage receptacles shall not be placed in the front setback area.

C. Common waste and other storage receptacles shall be architecturally screened and/or screened with landscaping so as to mask their appearance to residents, adjacent property owners, and the public rights-of-way. (Ord. 2020-613 § 11; Ord. 2008-397 § 4).

18.31.220 Impact fees.

Impact fees shall be assessed at the rates for multifamily dwelling units. (Ord. 2008-397 § 4).

18.31.230 Affordable housing.

If a cottage housing development consists of 10 units or more, one of the units must be an affordable housing unit affordable to households earning 100 percent or less of the median income, adjusted for household size.

Any affordable housing unit resulting from the provisions of this chapter must comply with the provisions of NMC 18.38.010, 18.38.040, and 18.38.050, as may be amended by the city, except for those sections specifically exempted by this chapter. (Ord. 2012-457 § 4; Ord. 2008-397 § 4).

18.31.240 Low impact development.

The use of low impact development (LID) techniques is encouraged where feasible and appropriate for cottage housing developments. (Ord. 2008-397 § 4).

18.31.250 Modifications.

The director may approve other methods provided:

A. The modification meets or exceeds the objectives and intent of the standard to be modified; and

B. The modification will not result in a development that is less compatible with neighboring land uses. (Ord. 2008-397 § 4).

18.31.260 Approval.

A. The city’s approval of a cottage housing development does not constitute approval of a subdivision. A lot that has cottage housing may not be subdivided unless all of the requirements of the zoning and subdivision codes are met.

B. Cottage housing development proposals shall be processed pursuant to Chapter 20.05 NMC, Binding Site Plans, and NMC Title 19, Administrative Procedures.

C. Cottage housing approval shall expire one year from the date of decision or conclusion of any appeal if progress is not made toward completing the project. (“Progress” means submitting a complete application for a permit to construct project improvements, i.e., engineering review permit application or building permit application.) A one-year extension may be granted by the director provided the applicant shows advancement of the project and good cause for the extension. (Ord. 2008-397 § 4).