Sammamish City Zoning Code
21.10 Inclusionary
Affordable Housing Program
21.10.010 Purpose
The incentives and regulations offered in this chapter are intended to be used by the City as one means of meeting its commitment to encourage housing affordable to all economic groups, and to meet its regional share of affordable housing requirements. The purpose of this chapter is to:
A. Help achieve comprehensive plan goals of affordable housing;
B. Help address the shortage of housing in the City for persons of low and moderate income;
C. Preserve and create opportunities for affordable housing as the City continues to grow;
D. Promote development of housing that would not otherwise be built in the City;
E. Create affordable housing opportunities as a result of increased development capacity across Sammamish neighborhoods;
F. Offer additional incentives to encourage construction of affordable housing units across Sammamish; and
G. Encourage developments that include affordable housing and that combine local incentives provided by the City with resources available from other public and private sources. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.020 Applicability
This chapter applies to:
A. All new residential projects located in R-1, R-4, R-6, R-8, MHO-1, MHO-2, and MHO-3 zones.
B. Within the Town Center pursuant to SMC 21.07.100. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.025 Definitions
The following definitions shall apply to the administration of this chapter. In addition, except as otherwise provided in this section, those definitions set forth in Chapter 21.04 SMC are adopted and incorporated into this section by reference.
“Bonus market rate unit” means an additional dwelling unit beyond the density limitations of a particular lot in exchange for an affordable housing unit or other public benefit determined by the City.
“Eligible household” means one or more adults and their dependents who certify that their annual household income does not exceed the applicable percent of the area median income, adjusted for household size, and who certify that they meet all qualifications for eligibility, including any requirements for recertification on income eligibility.
“Housing expense” means, in the case of renter-occupied housing, rent, tenant-paid utilities, one parking space, and other tenant expenses required for the dwelling unit; and in the case of owner-occupied housing, mortgage, mortgage insurance, property taxes, property insurance, and homeowner’s dues.
“Total floor area” means all habitable living space, measured from exterior walls. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.030 General Requirements
A. At least 10 percent of the units in new housing developments in the areas specified in SMC 21.10.020 must be affordable to households earning up to 80 percent AMI, adjusted for household size.
B. Each 50 percent AMI affordable housing unit provided counts as two 80 percent AMI affordable housing units for the purpose of satisfying the requirement under subsection A of this section.
C. The number of required affordable housing units is determined by multiplying the total number of housing units by 10 percent.
D. If the calculation results in whole numbers, then the required affordable housing units shall be constructed on site, unless an alternative option is approved by the Director pursuant to SMC 21.10.060.
E. If the calculation results in a fraction, then the required affordable housing units shall be satisfied either: (a) through payment of a fee-in-lieu, or (b) by constructing a complete affordable housing unit on site.
1. The square footage used to calculate the payment in lieu must be equal to the total floor area of all fee-eligible fractional units to be constructed on site of the subject project. When a whole affordable unit(s) and fractional unit(s) are required, applicants may select which project unit(s) are used to calculate the total net floor area.
Example: A project proposing construction of 24 units would be allowed to build 22 market-rate units and would be required to build two affordable units and pay a fee-in-lieu equal to the total floor area of four of the units selected by the applicant.
F. If applicable, any bonus market rate units shall not be included in the total number of the housing units when determining the number of required affordable housing units. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.050 Implementation Requirements
The following requirements must be met for all affordable housing units created through this chapter:
A. Affordable housing units that are provided under this section must remain as affordable housing for a minimum of 50 years from the date of initial owner occupancy for ownership affordable housing units and for the life of the project for rental affordable housing units. At the sole discretion of the Director, a shorter affordability time period, not to be less than 30 years, may be approved by the City for ownership affordable housing units, in order to meet federal financial underwriting guidelines. The property owner and City shall sign an Affordability Agreement pursuant to SMC 21.10.070 reflecting the requirements of this chapter.
B. Prior to the issuance of any permit(s), the Director shall review and approve the location and unit mix of the affordable housing units consistent with the following standards:
1. The location of the affordable housing units must be approved by the Director, with the intent that they generally be interspersed with all other dwelling units in the development.
2. The tenure (ownership or rental) of the affordable housing units must be the same as the tenure for the rest of the housing units in the development.
3. The affordable housing units must contain a mix of number of bedrooms that is generally proportionate to the bedroom mix of units in the overall development.
4. The affordable housing units must consist of a mix of housing structure types that is generally proportionate to the mix of housing structure types in the overall development. However, the Director has the discretion to approve proposals for the use of cottages, duplexes, triplexes, and other housing structure types, to meet the requirements of this section.
5. The size of the affordable housing units must be provided in a range of sizes comparable to those units that are available to other residents. Affordable housing units that are smaller than the other units with the same number of bedrooms in the development must be approved by the Director. In no case may the affordable housing units be more than 10 percent smaller than the comparable dwelling units in the development.
6. The exterior materials and design of the affordable housing units must be comparable with the other dwelling units in the development, with similarity in building finishes, rooflines and landscaping. The interior finish, durability, and quality of construction of the affordable housing units must at a minimum be comparable to entry level rental or ownership housing in the City.
7. The affordable housing units must include water and energy saving fixtures and support potential electrification hook-ups if the other dwelling units in the development contain those fixtures and potential hook ups.
C. Construction of the affordable housing units must be delivered at the same time as the construction of market rate dwelling units unless the requirements of this section are met through SMC 21.10.060. This is measured at the time of final inspection and occupancy. The City may withhold occupancy of market rate units if affordable units are not delivered consistent with this section. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.060 Whole Unit Alternative Compliance
A. While it is the City’s priority to provide affordable housing on the site of the lot generating the affordable housing requirement, the Director may approve a request to deviate from providing the affordable housing unit on site for projects that result in whole units of affordable housing if the applicant meets the intent of this section.
B. This alternative compliance option is only available for projects resulting in whole units of affordable housing. For projects resulting in fractional units, the affordable housing requirements shall be satisfied through the requirements defined in SMC 21.10.030.E. For projects that result in whole units plus fractional units, the affordable housing requirements of the whole unit may be satisfied as required by this section, while remnant fractional units provided by the requirements of SMC 21.10.030.E.
C. One or more of the following alternatives may be proposed by the applicant provided they can demonstrate and the Director determines that any alternative is more economically viable than providing affordable housing on site. Third-party verification at the expense of the applicant may be required. Housing units provided through an alternative compliance method must be based on providing the same type and tenure of units as the units in the project that give rise to the requirement.
1. Off-site construction of affordable housing units may be provided if the location chosen does not lead to undue concentration of affordable housing in any particular area of the City. Preference will be given to sites in within one-quarter mile of the project area.
2. Cash payments in lieu of constructing affordable housing units may be provided and will be used only for the subsequent provision of affordable housing units by the City or other housing provider approved by the Director.
3. Land dedication in lieu of constructing affordable housing units may be provided where the City is actively negotiating a development agreement with the applicant of the subject parcel for the construction of affordable housing unit(s) development.
D. Timing.
1. Excluding the alternative compliance for land dedication (subsection C.3 of this section), application for and approval by the Director for alternative compliance must be granted prior to issuing a building permit for the project, unless otherwise permitted by the Director.
2. Application for off-site alternative compliance must document the timing that off-site affordable housing units will be made available within six months of delivery of the last market rate unit within the development, and provide assurances to ensure completion of the off-site affordable housing units. The intent is for affordable housing units to be provided before or at the same time as the on-site market rate housing.
3. Timing of land dedication proposals must follow the requirements of the development agreement and must be adopted by the City Council prior to the issuance of any of market rate building permits for the parcel generating the affordable housing requirement. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.065 In-Lieu Fee Management
The following requirements apply to the collection and use of the cash payments received pursuant to SMC 21.10.030.C or 21.10.060.C.2:
A. Fee Amount and Payment.
1. The cash payment amount is specified in the City’s development fee schedule.
2. The payment obligation will be calculated prior to the issuance of building permits or if a land division is proposed, then prior to the issuance of the preliminary plat approval for the project.
3. The payment obligation is due upon sale of the subject parcel or occupancy, whichever occurs first.
B. Deposit of Fees. All in-lieu fees collected hereunder shall be deposited in a housing trust fund. The fund shall be administered by the City and shall be used only for the purpose of providing funding assistance for the provision of affordable housing units and the reasonable costs of administration consistent with the policies and programs contained in the housing element of the comprehensive plan.
C. Use of Fees. The location of affordable housing funded wholly or in part with the in-lieu fees must be supported by a policy maintained by the City Council. Exact use of fees will be adopted in the City fee resolution. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.070 Affordability Agreement
Prior to issuing any building permit, an agreement in a form approved by the director that addresses price restrictions, homebuyer or tenant qualifications, phasing of construction, marketing, monitoring of affordability, duration of affordability, and any other applicable topics of the affordable housing units shall be recorded with the King County Department of Records and Elections. This agreement shall be a covenant running with the land and shall be binding on the assigns, heirs and successors of the applicant.
The City may agree, at its sole discretion, to subordinate any affordable housing regulatory agreement for the purpose of enabling the owner to obtain financing for development of the property. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.080 Monitoring and Fee
The City reserves the right to establish in the affordability agreement authorized pursuant to SMC 21.10.070 monitoring fees to recover the City’s administrative cost of monitoring and enforcing compliance with the affordability agreement, which can be adjusted over time to account for inflation. The purpose of any monitoring fee is for the review and processing of documents to maintain compliance with income and affordability restrictions of the affordability agreement. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.090 Administrative Official
The Director shall be responsible for administration and enforcement of this chapter and is authorized to adopt administrative procedures, policies, rules, or guidance for implementation of this section, and prepare forms and applications necessary to carry out the purposes of this chapter. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))
21.10.100 Exemptions
The following are exempt from the requirements of this chapter:
A. Units with a total floor area of 1,500 square feet or less, including ADUs and cottage housing.
B. Units resulting from internal subdivision of existing structures.
C. Garage conversions.
D. Units being rebuilt, renovated, or remodeled, unless units are being enlarged above their existing size. Units being enlarged above their existing size shall be subject to payment of an in-lieu fee on a per square foot basis in accordance with SMC 21.10.065 for new total floor area beyond the original total floor area. Units that are being rebuilt, renovated, or remodeled and are being enlarged above their existing size and remain below the 1,500 total square foot exemption (existing size plus additional floor area added) listed with subsection A of this section shall remain exempt.
E. Bonus units generated from affordability, existing homes, or transit proximity specified in SMC 21.02.050. (Ord. O2025-583 § 2 (Att. A.12); Ord. O2024-578 § 2 (Att. A))