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A. Purpose. The R-20 Multifamily Urban Residential zone provides for multifamily residential neighborhoods on lands suitable for residential development with an allowed base density of 20 dwellings per gross acre. This designation provides for stable and attractive residential neighborhoods which have an urban character and a full range of public services and facilities. To complement the primarily residential nature of these zones, some nonresidential uses are allowed.

Figure 21.08.130
Typical R-20 Layouts

This sketch represents maximum allowance for structures, impervious surface & setbacks

Typical R-20 Layouts

LEGEND

A

FRONT SETBACK MINIMUM 20'-0"

B

SIDE STREET SETBACK MINIMUM 15'-0"

C

SIDE INTERIOR SETBACK 15'-0" (5'-0" FOR DETACHED HOUSING)

D

REAR SETBACK MINIMUM 10'-0"

E

LOT FRONTAGE MINIMUM 30'-0"

F

ALLOWED PROJECTION OF BUILDING EXTREMITIES INTO SETBACK

B. Maximum Development Yield. The following calculation provides a potential maximum development yield for a development utilizing the density bonuses available for the R-20 zone. The calculation is based on a development occurring on a one-acre lot. Please note that accessory dwelling units do not count toward maximum development yield.

Table 21.08.130A
Maximum Development Yield

Base Density

Available Density Bonuses

Maximum Density

20 dwelling units per gross acre

Green Building/Green Infrastructure Development: Up to 10 percent of base density

2.0 dwelling units allowed

Affordable Housing: Up to 15 percent of base density

3.0 dwelling units allowed

Total = 25 dwelling units per gross acre

C. Regulations Common to All Uses.

Table 21.08.130B
Regulations Common to All Uses

Regulation

Standard

Exceptions

Minimum

Average Lot Size

N/A

Required Density

65 percent of net acres

Lot Width Circle

N/A

Lot Frontage

30 feet

Setbacks

Front

20 feet

Side / Interior (each side)

15 feet

5 feet for detached dwelling units

Side Street

15 feet

Rear

10 feet

Alley

4 feet

Lake Sammamish

35 feet

Building Separation

15 feet

6 feet for single-family dwellings. 10 feet for 2-unit to 4-unit attached dwelling units.

Open Space

20 percent of total lot area

Landscaping

50 percent of total lot area

Maximum

Lot Coverage for Structures

60 percent of total lot area

Impervious Surface

75 percent of total lot area

Building Height

60 feet

30 feet in Shoreline Jurisdiction

Drive-through

n/a

Drive-through facilities are prohibited except where expressly permitted in the Allowed Uses and Special Regulations table below.

D. Allowed Uses and Special Regulations. The following table contains special zoning regulations that apply to uses in the R-20 zone. To use the chart, first read down the left-hand column titled “Use.” When you have located the use that interests you, read across to find regulations that apply to that use. Uses are permitted unless otherwise specified in the Special Regulations column. Permitted uses may require land use permit approval. See RZC 21.76.020, Overview of the Development Process, for more information. Uses not listed are not permitted.

Table 21.08.130C
Allowed Uses and Special Regulations

Section

Use

Parking Ratio:
unit of measure (minimum required; maximum allowed)

Special Regulations

Residential1

1

Detached dwelling unit

Dwelling unit (2.0)

2

Size-limited dwelling

3

Accessory dwelling unit (ADU)

ADU (1.0)

See RZC 21.08.220, Accessory Dwelling Units, for specific regulations which may apply.

4

Attached dwelling unit, 2-4 units

Studio dwelling unit (1.2)

1-bedroom dwelling unit (1.5)

2-bedroom dwelling unit (1.8)

3+-bedroom dwelling unit (2.0)

A. Permitted use in all neighborhoods. 

B. Please see RZC 21.08.260, Attached Dwelling Units, for specific regulations related to density, design, review and decision procedures, and affordable housing exceptions.

5

Multifamily structures

6

Manufactured home

Dwelling unit (2.0)

See RZC 21.08.320, Designated Manufactured Homes, Manufactured Homes, and Mobile Homes, for specific regulations which may apply.

7

Housing Services for the Elderly

See Special Regulations

A. Retirement residences are permitted through a subdivision or binding site plan with a maximum of 16 retirement residence units per acre. Without a subdivision or binding site plan, a Conditional Use Permit is required. See RZC 21.08.360, Retirement Residences, for specific regulations which may apply. 

B. A Conditional Use Permit is required for Residential Care Facilities

C. A Conditional Use Permit is required for Long-Term Care Facilities

D. Parking requirements are as follows:

1. Multifamily housing for senior citizens: Unit (0.5, 2.0) 

2. Nursing home or long-term care facility: four patient beds (1.0, 1.0) 

3. Retirement residence with no skilled nursing facility: Unit (1.0, 1.0) 

4. Retirement residence with skilled nursing facility: Worker on largest shift (1.25, 1.25) 

E. For Retirement Residences, a Traffic Mitigation Plan is required. See RZC 21.08.370.C.3.b.iii.

8

Adult family home

Dwelling unit (2.0)

Transportation, Communication, Information, and Utilities

9

Local utilities

Adequate to accommodate peak use.

10

Regional utilities

A Conditional Use Permit is required.

11

Heliport

N/A

A Conditional Use Permit is required. Does not include medical airlift. Permitted only abutting Lake Sammamish.

12

Float plane facility

N/A

A. A Conditional Use Permit is required. Permitted only abutting Lake Sammamish. 

B. Piers, docks, and floats associated with the operation of float planes shall meet, as a minimum, the location criteria contained in RZC 21.68.070, In-Water Structures. Piers and docks are also subject to standards for residential piers and docks contained in RZC 21.68.070.E, Piers, Docks, and Floats. (SMP) 

C. Only one float plane per lot is permitted. (SMP) 

D. Float planes shall observe speed regulations for watercraft and vessels contained in RMC 14.16.030, Speed Regulations, except that these speeds may be exceeded for a short duration of time during landing and takeoff of planes. (SMP) 

E. Float plane facilities or operation of float planes is prohibited on the Sammamish River, Bear Creek and Evans Creek. (SMP) 

F. Float plane facilities and operation shall comply with FAA standards, including standards for fueling, oil spill cleanup, firefighting equipment, and vehicle and pedestrian separation. (SMP)

13

Wireless Communication Facilities

See RZC 21.56, Wireless Communication Facilities, for specific development requirements.

Arts, Entertainment, and Recreation

15

Community indoor recreation

Adequate to accommodate peak use.

Includes noncommercial indoor recreation uses, such as community clubhouses, indoor swimming pools, and other similar facilities.

16

Parks, open space, trails and gardens

1,000 sq ft gfa (0, adequate to accommodate peak use)

Permitted if public or noncommercial. A Conditional Use Permit is required for commercial facilities.

17

Athletic, sports, and play fields

Adequate to accommodate peak use.

A Conditional Use Permit is required.

18

Golf course

19

Marine recreation

20

Commercial swimming pool

Education, Public Administration, Health Care, and Other Institutions

21

Day care center

Employee (1.0)

A Conditional Use Permit is required. See RZC 21.08.310, Day Care Centers, for specific regulations which may apply.

22

Family day care provider

Vehicle used by the business (1.0).

Family day care providers are permitted as home businesses. See RZC 21.08.340, Home Business, for specific regulations which may apply.

23

Public safety

Adequate to accommodate peak use

A Conditional Use Permit is required.

24

Grade schools (K-12)

25

Religious Institution

1,000 sq ft gfa for assembly (1.0) or 5 fixed seats (1.0); 3 seats (1.0).

A. Permitted use if less than 250 seats. A Conditional Use Permit is required for religious institutions with between 250 and 750 seats. See RZC 21.08.280, Churches, Temples, Synagogues and Other Places of Worship, for specific regulations which may apply.

B. A Traffic Mitigation Plan is required. See RZC 21.08.280.C.5.

Other

26

Home Business

Vehicle used by the business (1.0).

See RZC 21.08.340, Home Business, for specific regulations which may apply.

27

Roadside produce stand

N/A

28

Pier, dock, float

See RZC 21.68.070, In-Water Structures, for special height, setback and area requirements, (SMP)

29

Water-oriented accessory structure

See RZC 21.68.070.G, Water-Oriented Accessory Structures, for special height, setback and area requirements. (SMP)

Notes:

1Permanent supportive housing, as defined under RCW 36.70A.030, and transitional housing, as defined under RCW Chapter 84.36, are allowed in all land use districts where residential dwellings and/or hotel uses are allowed, subject to RZC 21.57.010,Permanent Supportive Housing, Transitional Housing, and Emergency Housing.

(Ord. 2652; Ord. 2709; Ord. 2803; Ord. 2919; Ord. 3074)

Effective on: 2/12/2022