The purpose of this middle housing chapter is to:

A. Implement Engrossed Second Substitute House Bill 1110 and Engrossed Substitute House Bill 2321, codified in RCW 36.70A.030, 36.70A.280, 36.70A.635, 36.70A.636, 36.70A.637, 36.70A.638, 43.21C.495, and 43.21C.450, and Chapters 64.32, 64.34, and 64.38, and 64.90 RCW, by providing land use, development, design, and other standards for middle housing developed on all lots zoned predominantly for residential use.

B. If necessary, supersede, preempt, and invalidate the city’s development regulations that conflict with this chapter. (Ord. 2025-671 § 10).

A. Nothing in this chapter prohibits the city from permitting detached single-family residences.

B. Nothing in this chapter prohibits the city from requiring any development, including middle housing development, to provide affordable housing, either on site or through an in-lieu payment, nor limit the city’s ability to expand or modify the requirements of an existing affordable housing program enacted under RCW 36.70A.540.

C. Nothing in this chapter requires the issuance of a building permit if other federal, state, and local requirements for a building permit are not met.

D. Nothing in this chapter affects or modifies the responsibilities of the city to plan for or provide “urban governmental services” as defined in RCW 36.70A.030.

E. The city shall not approve a building permit for middle housing without compliance with the adequate water supply requirements of RCW 19.27.097.

F. The city shall not require through development regulations any standards for middle housing that are more restrictive than those required for detached single-family residences, but may apply any objective development regulations that are required for detached single-family residences, including, but not limited to, setback, lot coverage, stormwater, clearing, and tree canopy and retention requirements.

G. The same development permit and environmental review processes shall apply to middle housing that apply to detached single-family residences, unless otherwise required by state law including, but not limited to, shoreline regulations under Chapter 90.58 RCW, building codes under Chapter 19.27 RCW, energy codes under Chapter 19.27A RCW, or electrical codes under Chapter 19.28 RCW. (Ord. 2025-671 § 10).

A. The provisions of this chapter shall apply to all lots zoned predominantly for residential use, unless otherwise noted.

B. The provisions of this chapter do not apply to:

1. Portions of a lot, parcel, or tract designated with critical areas designated under RCW 36.70A.170 or their buffers as required by RCW 36.70A.170, except for critical aquifer recharge areas where a single-family detached house is an allowed use; provided, that any requirements to maintain aquifer recharge are met.

2. A watershed serving a reservoir for potable water if that watershed is or was listed, as of July 23, 2023, as impaired or threatened under Section 303(d) of the Federal Clean Water Act (33 U.S.C. Sec. 1313(d)).

3. Lots that have been designated urban separators by countywide planning policies as of July 23, 2023.

4. A lot that was created through the splitting of a single residential lot. (Ord. 2025-671 § 10).

A. The permitted unit density on all lots zoned predominantly for residential use is two units per lot, unless zoning permitting higher densities or intensities applies.

B. The standard of subsection (A) of this section does not apply to lots after subdivision below 1,000 square feet unless the city has a smaller allowable lot size in the zone.

C. Accessory dwelling units do not count as units for the purposes of this section. (Ord. 2025-671 § 10).

A. The city shall not require through development regulations any standards for middle housing that are more restrictive than those required for detached single-family residences, but may apply any objective development regulations that are required for detached single-family residences. This includes, but is not limited to, the following types of dimensional standards: building height, setbacks, lot coverage, floor area ratio, lot area and lot dimensions, impervious surface, open space, and landscaped area standards.

B. Lot area requirements and density shall comply with NMC 18.19.040. Other restrictions, such as minimum lot area per unit, or maximum number of housing units per acre, are invalid in relationship to the minimum number of units per lot that the city must allow under RCW 36.70A.635. Unit lot subdivisions may be zero lot line between unit lots, but the standards of Chapter 18.12 NMC apply at the parent lot level. (Ord. 2025-671 § 10).

Subject to the requirements of RCW 36.70A.635(5), on all lots zoned predominantly for residential use the following uses are permitted by right, unless zoning permitting higher densities or intensities than those listed in NMC 18.19.040 applies:

A. Duplexes.

B. Stacked flats.

C. Cottage housing.

D. Courtyard apartments. (Ord. 2025-671 § 10).

Article I. Cottage Housing Development

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 multifamily developments where allowed pursuant to Chapter 18.08 NMC, Permitted Uses. (Ord. 2025-671 § 10).

Accessory dwelling units shall not be permitted in cottage housing developments. (Ord. 2025-671 § 10).

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. 2025-671 § 10).

Courtyard apartments shall be allowed and regulated under the provisions of Article II of this chapter with the exception that some or all of the units may be attached, and that all units shall border a common yard or court on two or three sides. (Ord. 2025-671 § 10).

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 two times the base density allowed in the underlying zone. (Ord. 2025-671 § 10).

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. Cottages may not exceed a floor area of 1,500 square feet on average in a development and no cottage shall be more than 1,700 square feet.

C. 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. (Ord. 2025-671 § 10).

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 five 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. 2025-671 § 10).

A. Quantity of Open Space. A minimum of 400 square feet per unit or 20 percent of lot size of landscaped open space, whichever is larger, 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 against the 400 square feet requirement in subsection (A) of this section, and the 20-percent open space requirement in the same subsection would be exclusive of critical areas and their buffers.

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. 2025-671 § 10).

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. No off-street parking shall be required within one-half mile walking distance of a major transit stop.

b. A maximum of one off-street parking space per unit shall be required on lots no greater than 6,000 square feet, before any zero lot line subdivisions or lot splits.

c. A maximum of two off-street parking spaces per unit shall be required on lots greater than 6,000 square feet before any zero lot line subdivisions or lot splits.

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 precludes the use of the parking spaces for vehicles is prohibited.

E. The design of carports must include rooflines similar and compatible to those of the dwelling units within the development. (Ord. 2025-671 § 10).

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

B. 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. 2025-671 § 10).

Impact fees shall be assessed at the rates for multifamily dwelling units. (Ord. 2025-671 § 10).

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. 2025-671 § 10).

The use of low impact development (LID) techniques is encouraged where feasible and appropriate for cottage housing developments. (Ord. 2025-671 § 10).

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. 2025-671 § 10).

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, or Chapter 20.09 NMC, Unit Lot Subdivisions, as practically applicable, 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. 2025-671 § 10).