Cottage Housing

Cottage Housing Ordinance Adopted

On December 21, 2016, the Snohomish County Council adopted a cottage housing ordinance (Amended Ordinance No. 16-073). The adopted ordinance was amended to:

The adopted cottage housing ordinance will do the following:

  • Establish revised site layout, building orientation, open space and amenity, pedestrian circulation, and architectural and design standards;
  • Provide a density bonus for cottage housing development equal to twice that otherwise allowed in the underlying zone;
  • Allow community buildings, shared garages, and accessory structures in cottage housing developments;
  • Increase maximum building height limits to 30 feet, lot coverage allowances to 40%, and dwelling unit sizes up to 2,400 square feet for cottage housing developments;
  • Reduce most setback requirements;
  • Authorize cottage housing developments as a Permitted use in the R-9,600, R-8,400, R-7,200, T, and LMDR zones, streamlining and altering review processes for such development applications;
  • Make technical amendments to roads and access provisions;
  • Eliminate landscaping buffer requirements for cottage housing developments adjacent to R-9,600 and R-8,400 zones;
  • Allow subdivision of cottage housing developments;
  • Establish "common open space", "private open space", "community building" definitions and revise certain other definitions;
  • Generally prohibit accessory apartments in cottage housing developments; and
  • Establish a specific review fee for cottage housing developments.

The ordinance became effective on February 19, 2017.

New: Updated Checklist and Bulletin

PDS is developing a new bulletin for cottage housing (Bulletin #79 (PDF)), which summarizes the new code. A revised checklist has been developed for both SFDU and Cottage Housing, which became effective on April 3, 2017.


Snohomish County first approached cottage housing as a new housing option in 2005. As part of the Urban Centers Demonstration Program, cottage housing was envisioned as a transitional density between larger scale developments and lower density residential areas. Regionally, cottage housing was increasingly becoming a popular housing type. Many local jurisdictions like Shoreline and Mill Creek had experienced success in realizing cottage housing communities in their own backyards. Snohomish County took cues from those successes in tailoring cottage housing practices to local conditions here.

As work began in 2006 on a broader set of design standards for residential development, the focus of cottage housing shifted away from urban centers and instead toward medium and low density residential areas. This led to regulations adopted in 2009, which allowed cottage housing in five residential zones and provided bulk requirements, design standards, and a new definition of cottage housing to the code.

What Cottage Housing Is

Cottage housing (PDF) is a mildly dense, small scale housing form. Units are typically built at or below 1,200 square feet with modest dimensions. By design, cottage housing is geared toward single-family tenancy and can be constructed as either attached or detached units. The nature of cottage housing is one of community where shared space and semi-private space are favored over purely private space. Cottage housing developments are usually focused around community courtyards where housing clusters numbering four to twelve units open onto the shared space.

Cottage housing can provide an affordable alternative to larger single-family homes and suit the needs of many different household types. They're especially adept at serving smaller families, single individuals, the elderly, and those with mobility challenges.

These attributes are perhaps best represented in the collage below:

How It's Regulated Now

Snohomish County cottage housing regulations are codified in SCC 30.41G. Those regulations are primarily designed to address site layout, amenities, building sizes and setbacks, and architectural features.

Cottage housing is limited to a handful of residential zones, including the following: R-9,600, R-8,400, R-7,200, T, and LDMR. As an incentive to build smaller dwelling units, the cottage housing code provides a density bonus of up to 1.2 times the underlying zoning maximum.