The purpose of this chapter is to:
A. 
Provide density incentives to developers of residential property, in exchange for public benefits to help achieve comprehensive plan goals of affordable housing, open space protection, and parkland acquisition by:
1. 
Defining in quantified terms the public benefits that can be used to earn density incentives;
2. 
Providing rules and formulas for computing density incentives earned by each benefit.
B. 
Provide a method to realize the development potential of:
1. 
Sites containing critical areas or of unique size or shape;
2. 
Specific sites preserved in order to achieve comprehensive plan goals as identified by the city council.
C. 
Provide a review process to allow evaluation of proposed density increases, using residential density incentives and the public benefits offered to earn them.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0481 § 2 (Exh. A); Ord. 21-0521 § 3 (Exh. B))
Residential density incentives (RDIs) shall be used only on sites served by public sewers and only in the following zones:
A. 
In R-4 through R-24, downtown residential, and urban residential zones; and
B. 
In DC, NB, CB, UC, WC, and RB zones when part of a multiple-family dwelling or mixed use development.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 14-0391 § 2 (Exh. 1); Ord. 19-0481 § 2 (Exh. A); Ord. 23-0574 § 2 (Exh. A))
A. 
The public benefits eligible to earn increased densities, and the maximum incentive to be earned by each benefit, are in subsection E of this section. The density incentive is expressed as additional bonus dwelling units, or fractions of dwelling units, earned per amount of public benefit provided.
B. 
Bonus dwelling units may be earned through any combination of the listed public benefits.
C. 
Bonus dwelling units may also be earned and transferred to the project site through the transfer of density credit (TDC) process from sites other than that of the RDI development.
D. 
Residential development in R-4 through R-24 and downtown residential zones with property-specific development standards requiring any public benefit enumerated in this chapter shall be eligible to earn bonus dwelling units in accordance with subsection E of this section if the public benefits provided exceed the basic development standards of this title. If a development is located in a special overlay district, bonus units may be earned if the development provides public benefits exceeding corresponding standards of the special district.
E. 
The following are the public benefits eligible to earn density incentives through RDI review:
BENEFIT
DENSITY INCENTIVE
1.
AFFORDABLE HOUSING
 
a.
Benefit units consisting of rental housing permanently affordable to very low-income households, as defined in KMC § 18.20.098. A covenant on the site that specifies the income level being served, rent levels and requirements for reporting to the City shall be recorded at final approval.
2.0 bonus units per benefit unit.
b.
Benefit units consisting of assisted housing units 600 square feet or less.
1.0 bonus unit per benefit unit.
c.
Benefit units consisting of rental housing permanently affordable (as defined in KMC § 18.20.098) to households with incomes at or below 70 percent of King County median income, adjusted for household size. A covenant on the site that specifies the income level being served, rent levels and requirements for reporting to the City shall be recorded at final approval.
1.0 bonus unit per benefit unit.
d.
Benefit units consisting of low-income, owner-occupied housing (as defined in KMC § 18.20.098), reserved for eligible home buyers. A covenant on the site that specifies the income level and other aspects of buyer eligibility, price levels and requirements for reporting to the City shall be recorded at final approval.
1.0 bonus unit per benefit unit.
e.
Benefit units consisting of very low-income, owner-occupied housing (as defined in KMC § 18.20.098), reserved for eligible home buyers. A covenant on the site that specifies the income level and other aspects of buyer eligibility, price levels, and requirements for reporting to the City shall be recorded at final approval.
2.0 bonus units per benefit unit.
f.
Benefit units consisting of manufactured housing community space or pad reserved for the relocation of an insignia or noninsignia mobile home, that has been or will be displaced due to closure of a manufactured housing community located in the City.
1.0 bonus unit per benefit unit.
g.
Affordable housing units provided under this section shall remain affordable housing for a minimum of 50 years from the date of initial sale, if owner-occupied, or the life of the project (i.e., the duration of the property’s residential use), if renter-occupied.
 
2.
OPEN SPACE, TRAILS AND PARKS
 
a.
Dedication of park site or trail right-of-way meeting the City location and size standards for neighborhood, community or regional park, or trail, and accepted by the department.
0.5 bonus unit per acre of park area or quarter-mile of trail exceeding the minimum requirement of Chapter 18.30 KMC for on-site recreation space or trail corridors, computed on the number of dwelling units permitted by the site’s base density.
b.
Improvement of dedicated park site to City standards for developed parks.
0.75 bonus unit per acre of park improvement. If the applicant is dedicating the site of the improvements, the bonus units earned by improvements shall be added to the bonus units earned by the dedication.
c.
Improvement of dedicated trail segment to City standards.
1.8 bonus units per quarter-mile of trail constructed to City standard for pedestrian trails; or
2.5 bonus units per quarter-mile of trail constructed to City standard for multipurpose trails (pedestrian/bicycle/equestrian).
Shorter segments shall be awarded bonus units on a pro rata basis. If the applicant is dedicating the site of the improvements, the bonus units earned by improvements shall be added to the bonus units earned by the dedication.
d.
Dedication of open space, meeting City acquisition standards to the City or a qualified public or private organization such as a nature conservancy.
0.5 bonus unit per acre of open space.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0481 § 2 (Exh. A); Ord. 23-0574 § 2 (Exh. A))
A. 
The formula for calculating the total number of dwelling units permitted through RDI review is as follows:
DUs allowed by RDI site base Density
+
Bonus DUs
+
DUs allowed by sending site density (if any)
=
TOTAL RDI DUs
B. 
The total dwelling units permitted through RDI review shall be calculated using the following steps:
1. 
Calculate the number of dwellings permitted by the base density of the site in accordance with Chapter 18.30 KMC;
2. 
Calculate the total number of bonus dwelling units earned by providing the public benefits listed in KMC § 18.80.040;
3. 
Add the number of bonus dwelling units earned to the number of dwelling units permitted by the base density;
4. 
Add the number of dwelling units permitted by the base density of the site sending TDCs, if any;
5. 
Round fractional dwelling units to the nearest whole number; 0.49 or less dwelling units are rounded down; and
6. 
On sites with more than one zone or zone density, the maximum density shall be calculated for the site area of each zone. Bonus units may be reallocated within the zones in the same manner set forth for base units.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0481 § 2 (Exh. A))
A. 
All RDI proposals shall be reviewed concurrently with a primary proposal to consider the proposed site plan and methods used to earn extra density.
1. 
When the primary proposal requires a public hearing under this code or KMC Title 17, the public hearing on the primary proposal shall serve as the hearing on the RDI proposal, and the reviewing authority shall make a consolidated decision on the proposed development and use of RDI;
2. 
When the primary proposal does not require a public hearing under this code or KMC Title 17, the RDI proposal shall be processed as a Type 2 land use decision, unless otherwise authorized by KMC § 18.77.060(A), subject to the decision criteria for conditional use permits outlined in Chapter 18.115 KMC; and
3. 
The notice for the RDI proposal also shall include the development’s proposed density and a general description of the public benefits offered to earn extra density.
B. 
RDI applications which propose to earn bonus units by dedicating real property or public facilities shall include a letter from the receiving agency certifying that the proposed dedication qualifies for the density incentive and will be accepted by the agency or other qualifying organization.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0481 § 2 (Exh. A); Ord. 21-0521 § 3 (Exh. B))
When issuing building permits in an approved RDI development, the department may allow minor adjustments in the approved site plan involving the location or dimensions of buildings or landscaping, provided such adjustments shall not:
A. 
Increase the number of dwelling units;
B. 
Decrease the amount of perimeter landscaping (if any);
C. 
Decrease residential parking facilities (unless the number of dwelling units is decreased);
D. 
Locate structures closer to any site boundary line; or
E. 
Change the locations of any points of ingress and egress to the site.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0481 § 2 (Exh. A))
A. 
RDI developments shall comply with dimensional standards of the zone with a base density most closely comparable to the total approved density of the RDI development; provided, that an RDI proposal in the R-4 through R-6 zones shall conform to the height requirements of the underlying zone in which it is located.
B. 
RDI developments in the R-4 through R-6 zones shall be landscaped as follows:
1. 
When 75 percent or more of the units in the RDI development consist of townhouses or apartments, the development shall provide perimeter landscaping and tree retention in accordance with Chapters 18.35 and 18.57 KMC for townhouse or apartment projects.
2. 
When less than 75 percent of the units in the RDI consist of townhouses or apartments, the development shall provide landscaping and tree retention in accordance with Chapters 18.35 and 18.57 KMC for townhouses or apartments on the portion(s) of the development containing such units; provided, that if buildings containing such units are more than 100 feet from the development’s perimeter, the required landscaping may be reduced by 50 percent.
3. 
All other portions of the RDI shall provide landscaping or retain trees in accordance with Chapters 18.35 and 18.57 KMC.
C. 
RDI developments in all other zones shall be landscaped or retain trees in accordance with Chapters 18.35 and 18.57 KMC.
D. 
RDI developments shall provide parking as follows:
1. 
Projects with 100 percent affordable housing shall provide one off-street parking space per unit. The city manager may require additional parking, up to the maximum standards for attached dwelling units, which may be provided in common parking areas.
2. 
All other RDI proposals shall provide parking for:
a. 
Market rate/bonus units at levels consistent with Chapter 18.40 KMC; and
b. 
Benefit units at:
(1) 
One or two bedrooms: one parking space per unit;
(2) 
Three bedrooms: one and one-half parking spaces per unit;
(3) 
Parking may be further reduced if a parking demand analysis is provided per KMC § 18.40.030(B).
E. 
RDI developments shall provide on-site recreation space as follows:
1. 
Projects with 100 percent affordable housing shall provide recreation space at 50 percent of the levels required in Chapter 18.30 KMC.
2. 
All other RDI proposals shall provide recreation space for:
a. 
Market rate/bonus units at levels consistent with Chapter 18.30 KMC; and
b. 
Benefit units at 50 percent of the levels required for market rate/bonus units.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0481 § 2 (Exh. A))
In order to realize the development potential of sites containing critical areas or of unique size or shape, or sites preserved in order to attain comprehensive plan goals, an opportunity to transfer unused density from one site to another shall be provided. Transfer of density credit transactions shall be handled between the private parties, with documentation provided to the City, until such time as the City enters into a formalized transfer of development rights (TDR) process through King County or another agency.
A. 
Transfer of Density from Sites Constrained by Critical Areas or of Unique Size and Shape. A development proponent may apply to transfer unused density from a site constrained by critical areas or of unique size or shape to another site through a Type 2 land use decision, unless otherwise authorized by KMC § 18.77.060(A).
1. 
The number of density credits that a sending site is eligible to send to a receiving site shall be determined by applying the base density of the zone the sending site is located in to the total sending site area, less any portion of the sending site already in a conservation easement or other encumbrance, or any land area already used to calculate residential density for other development on the sending site. A plot plan showing critical areas and buffers, conservation easements or other encumbrances shall be submitted as part of the development application to demonstrate compliance with the density calculation rules set forth in Chapter 18.30 KMC.
2. 
Sending sites with critical areas that have been declared unbuildable under Chapter 18.30 KMC shall be considered to have a base density calculated in accordance with that chapter, except that the areas of the sending and receiving sites shall be combined to calculate the overall site percentage of critical areas and buffers necessary for determining the allowable density credit as set forth in Chapter 18.55 KMC.
3. 
When the sending site consists only of a portion(s) of an unsubdivided parcel, said portion(s) shall be segregated from the remainder of the lot pursuant to KMC Title 17 or deed restrictions documenting the density credit transfers shall be recorded with the title to both the sending and receiving sites. A parcel need not segregate a sending site from the remainder of the parcel when the entire parcel is subject to a conservation easement pursuant to subsection (A)(4) of this section.
4. 
Conservation easements shall be required for land contained in the sending site, whether or not such land is dedicated, as follows: a conservation easement shall be recorded on the sending site to indicate development limitations on the sending site.
B. 
Transfer of Density from Sites in Order to Attain Comprehensive Plan Goals. A development proponent may apply to transfer unused density from a sending site to a receiving site to achieve comprehensive plan goals as specified by the city council. The city council shall identify by ordinance circumstances in which this code section may be applied.
1. 
As of April 23, 2019, the city council has determined that unused density may be transferred from a property zoned MHC to a receiving site if long-term preservation of the manufactured housing community is assured. Unused density shall be defined as the number of dwelling units allowable under existing zoning as of April 22, 2019, less the number of existing dwelling units on the property as of April 23, 2019, multiplied by two and one-half.
2. 
Density shall not be transferred to projects in the R-1, R-4 or R-6 zoning districts.
C. 
Density credits from one sending site may be allocated to more than one receiving site.
D. 
The transfer of density request shall be processed as part of the underlying permit for the project on the receiving site.
E. 
Upon submitting an application to develop a receiving site under the provisions of this section, the applicant shall provide evidence of ownership or full legal control of the density credits proposed to be used in calculating total density on the receiving site.
F. 
Density credits from a sending site shall be considered transferred to a receiving site when the sending site is permanently protected by a land dedication, conservation easement or preservation agreement submitted to and approved by the city manager. This document shall be recorded with King County prior to approval of the receiving site permit.
G. 
TDC developments shall comply with dimensional standards of the zone with a base density most closely comparable to the total approved density of the TDC development.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 19-0481 § 2 (Exh. A); Ord. 21-0521 § 3 (Exh. B))