(1) 
This chapter applies to the following zoning districts which are zones predominately for residential use in Des Moines and are therefore subject to E2SHB 1110 and ESHB 2321:
(a) 
R-SE: Suburban Estate Zone;
(b) 
R-SR: Suburban Residential Zone;
(c) 
Single-Family Residential (SFR) Zones designated as: RS-15,000; RS-9,600; RS-8,400; RS-7,200; and RS-4,000;
(d) 
RA-3600: Attached Townhouse and Duplex 3,600 Zone;
(e) 
RM-2400: Multifamily 2,400 Zone.
(2) 
The provisions of this chapter do not apply to:
(a) 
Portions of a lot, parcel, or tract designated with critical areas or their buffers as identified in chapter 16.10 DMMC (except that restrictions for critical aquifer recharge areas in DMMC § 16.10.260 are not included in this limitation).
(b) 
A lot that was created through the splitting of a single residential lot or via unit lot subdivision.
(Ord. 1821 § 6, 2025)
The permitted unit density (the number of dwelling units allowed on a lot; provided, that the lot is equal to or greater than 1,000 square feet and is a "parent lot" and not a "unit lot" or lot created from "lot splitting") is the greater of four units per lot or 24 units per acre, unless the zoning yields a high unit count for the lot.
(Ord. 1821 § 8, 2025)
(1) 
An accessory dwelling unit (ADU) is considered a dwelling unit when calculating permitted unit density and determining the number of units allowed on a lot or as part of a development proposal. Example: If four units are allowed on a lot and a fourplex has been developed, no ADUs may be added.
(2) 
ADUs must be accessory to a single-family home or a middle housing unit. No more than three ADUs may be included on a single lot; provided, that this will apply to the "parent lot" in cases where unit lot subdivision has occurred.
(3) 
ADUs situated in a single-family residential zone (zones beginning with RS-) are additionally subject to the standards contained in DMMC § 18.55.140.
(Ord. 1821 § 9, 2025)
(1) 
Chapter 18.155 DMMC, Multifamily Recreation Areas, applies to developments that are established under the middle housing provisions and standards as set out by this chapter, when a multifamily building or complex is established having four or more units; provided, that:
(a) 
The requirements of DMMC § 18.155.060, Play space for preadolescent children, do not apply for projects that are built under the middle housing provisions.
(b) 
Chapter 18.155 DMMC does not apply to cottage housing, which instead has a specific common space requirement.
(Ord. 1821 § 10, 2025)
(1) 
These design standards do not apply to the conversion of a structure to a middle housing type with up to four attached units, if the floor area of the structure does not increase more than 50 percent.
(2) 
The purpose of these standards is to promote compatibility of middle housing with other residential uses, including single-family houses; deemphasize garages and driveways as major visual elements along the street; provide clear and accessible pedestrian routes between buildings and street; and implement the definitions of cottage housing provided by state law.
(3) 
The process used for reviewing compliance with middle housing design standards shall be administrative design review.
(4) 
Cottage Housing Standards.
(a) 
Open Space. Open space shall be provided equal to a minimum 20 percent of the lot size. This may include common open space, private open space, setbacks, critical areas, and other open space.
(b) 
Common Open Space.
(i) 
At least one outdoor common open space is required.
(ii) 
Common open space shall be provided equal to a minimum of 300 square feet per cottage. Each common open space shall have a minimum dimension of 15 feet on any side.
(iii) 
Orientation. Common open space shall be bordered by cottages on at least two sides. At least half of cottage units in the development shall abut a common open space and have the primary entrance facing the common open space.
(iv) 
Parking areas and vehicular areas shall not qualify as common open space.
(v) 
Critical areas and their buffers, including steep slopes, shall not qualify as common open space.
(c) 
Entries. All cottages shall feature a roofed porch at least 60 square feet in size with a minimum dimension of five feet on any side facing the street and/or common open space.
(d) 
Community Building. A cottage housing development shall contain no more than one community building and the community building shall have no more than 2,400 square feet of net floor area, excluding attached garages.
(Ord. 1821 § 11, 2025)
(1) 
Pedestrian Access. A paved pedestrian connection at least three feet wide is required between each middle housing building and the sidewalk (or the street if there is no sidewalk). Driveways may be used to meet this requirement.
(2) 
Vehicle Access, Carports, Garages, and Driveways – For Middle Housing Projects.
(a) 
For lots abutting an improved alley that meets the City's standard for width, vehicular access shall be taken from the alley. Lots without access to an improved alley and taking vehicular access from a street shall meet the standards in subsections (2)(b) through (2)(d) of this section:
(b) 
Garages, driveways, and off-street parking areas shall not be located between a building and a street, except when any of the following conditions are met:
(i) 
The combined width of all garages, driveways, and off-street parking areas does not exceed a total of 60 percent of the length of the street frontage property line. This standard applies to buildings and not individual units [see option a in Figure 18.57.090]; or
(ii) 
The garage, driveway, or off-street parking area is separated from the street property line by a dwelling [see option b in Figure 18.57.090]; or
(iii) 
The garage, driveway, or off-street parking is located more than 100 feet from a street [see option c in Figure 18.57.090].
Figure 18.57.090
(c) 
All detached garages and carports shall not protrude beyond the front building facade.
(d) 
The adopted "City of Des Moines Street Development Standards" (as amended) for driveway separation and access from collector streets and arterial streets shall apply.
(Ord. 1821 § 12, 2025)
(1) 
Transportation, Lot Access and Road Standards. The adopted "City of Des Moines Street Development Standards" (as amended) apply to middle housing; provided, that regulations for driveways, frontage improvements, alley improvements, and other transportation public works and engineering standards which are more restrictive for middle housing than for detached single-family residences shall only apply where life-safety provisions are involved.
(2) 
This section is not intended to limit the applicability of the adopted International Fire Code and the adopted "City of Des Moines Street Development Standards" (as amended).
(Ord. 1821 § 14, 2025)