Affordable Housing Planning Resources

 Authorize cluster zoning or lot size averaging in all zoning districts that permit single-family residences.

LOT SIZE AVERAGING

• Lot size averaging guidance by Washington Realtors
• Information on lot size averaging by PRSC
• Bellevue - Lot Size Averaging 20.017
• Everett - Lot Area Averaging:39.130 (See C. Minimum Lot Area); Cluster Alternative for Subdividing: 19.39.130 (See E. Minimum Lot Area - Cluster Alternative for Subdividing), see also Cluster short subdivision and Cluster subdivision within the code
• Kirkland - Lot Averaging: 28.040.
• Lake Stevens - Lot Size Averaging: 48.085, Cluster Subdivision: 14.18.310 - applicable in any single-family residential zoning district, lot sizes and lot widths may be reduced by up to 20% of the dimensional standards with reductions reserved as open space.
• Sultan - Lot Averaging: Chapter 19.44
• Snohomish County - Lot Size Averaging: 23.210, Clustering in rural areas (various places).  (Although this is a county example, many requirements could be adjusted for a city's unique needs.)
• Tacoma - see this information for a summary.

 CLUSTER ZONING

• Black Diamond - Residential Cluster Development: Chapter 18.86. All residential zoning districts are eligible for cluster development. Cluster development may be applied to both multi-family and attached/detached single-family residential developments of three or more dwelling units; reductions in lot size of 30-45%, with deviations in other lot standards possible; remaining land is conserved as open space.
• Bothell - Clustered subdivisions: 30.070. City-wide clustered subdivision PUDs may include detached or attached residential developments on individual lots where the development preserves open space. Cluster subdivision PUDs allow minimum lot area and minimum lot circle diameter in five residential zones to be reduced by up to 50 percent, along with other regulation waivers or modifications (12.30.070). Specific clustering provisions for the Fitzgerald/35^th Avenue SE Subarea are in BMC 12.52.040.
• Edgewood - Residential cluster development (RCD): 50.035. A RCD constitutes an overlay district and is applicable within all residential and mixed use zoning districts, as well as commercial and town center areas. Modifications in minimum lot size, setbacks, maximum building footprints, lot coverage and impervious surface coverage may be granted, but minimum common open space must be provided (15-30% depending on base zoning).
• Federal Way - Cluster subdivision: 55.040. Applies to both long and short subdivisions to provide design flexibility, affordable housing, usable open space, and retention of native vegetation. Lots may be reduced in size up to one-half the underlying zoning requirement, provided other conditions are met, and 15 percent of the subdivision must remain as common open space. Provisions include requirements for compatibility with adjacent properties.
• Ilwaco - Cluster development: 29.047.  Allowed in the R-3 Resort District to allow development that adheres to the general intent of the underlying code while allowing variations from specific standards, while the additional land that would have been allocated to individual lots is converted to common shared open space for the development's residents.
• Kent City - Clustering in urban separators (12.04.263) and Clustering in residential zones outside urban separators (12.04.264) - different clustering techniques depending on the location within the city. Both require common open space (50% and 25%, respectively) for the advantages of clustering provided in the code.
• Rainier - Cluster development: 164. Cluster developments must be a minimum of two acres. One-half of lots within the cluster housing planned developments (CHPDs) may be subdivided at 25% of the minimum size required within the underlying zoning density requirements, and setbacks and lot configurations may also be reduced. Remaining lands within CPHD shall be placed in a separate tract with common ownership.