Subdivisions (Plats)

The Basics

Planning and Development Services (PDS) reviews subdivisions (also commonly referred to as "plats") for compliance with County subdivision codes. There are two broad categories of subdivisions that PDS processes: short plats and long plats. Subdivision type is determined by the number of lots proposed and whether the subject site(s) is/are located in rural or Urban Growth Areas (UGAs). When a proposed subdivision is located outside of the UGA, four lots or less constitutes a short plat while proposed subdivisions located inside the UGA containing nine lots or less constitute a short plat. When a proposed subdivision exceeds these numbers for lot, it constitutes a long plat (use our interactive PDS Map Portal to determine if a property is located within or outside the UGA).

Long Subdivisions and Short Subdivisions can come in a variety of forms for different project types, such as: Townhouse Unit Lot Subdivisions, Planned Residential Development Subdivisions, Rural Cluster Subdivisions, or Lot Size Averaging Subdivisions. While each type has different requirements and processes, all subdivision types involve a preliminary plat, civil engineering review and construction phase, and final plat process.

Antique town plat of Yew

For a full list of applicable fees, consult the County's fee code subdivision and land disturbing activity fees to estimate total review costs.

Preliminary Plat Process

The preliminary plat process is the initial project proposal stage of any subdivision. Applicants present all pertinent information regarding the proposal, which may include documents, such as: traffic studies, drainage reports environmental and geotechnical studies, tree canopy retention plans, proposed landscaping, and a preliminary plat site plan layout. A review team evaluates the project proposal for consistency with all applicable regulations and policies that may affect the project. Ultimately, the review staff prepare a recommendation to the Hearing Examiner (or administrative decision in certain cases) for the approval or denial of the project with project-specific conditions.

The preliminary plat process ensures that there is a public involvement process for the land use action. At the time of application, the public and property owners in proximity to the project site receive a project notice by mail, newspaper, and onsite. Individuals can request to become a party-of-record and will be notified of any future hearings or decisions on the application.

Submittal and resubmittal. Submittal of preliminary plats are accepted at Additional reviews of projects must be resubmitted through

Applications and checklists. Preliminary subdivisions and short subdivisions are subject to a wide variety of applications, checklists, and forms depending on the proposal type and location. All preliminary subdivisions and short subdivisions require a Master Land Use Permit Application, and the documents listed in the relevant submittal checklist. Applicants will need to determine what type of subdivision proposal they are pursuing and choose the appropriate checklist for their preliminary proposal. A proposal could include, for instance, a rural subdivision or short subdivision, an urban subdivision or short subdivision, a planned residential development subdivision or short subdivision, or a rural cluster subdivision or short subdivision

A project may be required to submit a SEPA Checklist (Environmental Review) with the primary application if it meets or exceeds a SEPA threshold. Other applications and checklists may apply depending upon the project proposal and site conditions. For additional details on short plats or rural cluster subdivisions (in rural areas), please be sure to consult the assistance bulletins on those topics (Short Subdivision (Short Plat) Approval (Assistance Bulletin #8) and Rural Cluster Subdivisions (Assistance Bulletin #44), respectively).

Final Plat Process

The County ensures that all plats conform to the requirements of preliminary plat approval, County checklists, State surveying standards, and other legal issues of a plat. During review of the final plat, PDS staff checks submitted maps for consistency with the neat and approximate layout of the preliminary plat map(s), Hearing Examiner or administrative decision, and subsequent minor revisions (if any). Maps are also reviewed for their conformance to requirements set forth in Department checklists, construction as-builts, standard surveying practices, and companion documents, such as: title reports, CC&Rs, and lot calculations.

Final plats typically undergo two standard reviews by PDS and Public Works staff. Survey field checks are conducted during the second review. Applicants must address all markups on maps and documents in full, and ensure that the site is properly marked and staked in the field for PDS field review. Failure to do so may be result in additional reviews or rejection of resubmittal documents.

During review of final plats, applicants should work with other agencies to complete the installation or approval of project utility services. Applicants should directly contact the Snohomish County Health Department (SHD), Snohomish County PUD (electricity), and their local water and sewer district(s) (or in the case of on-site septic and well systems, SHD) to gain necessary approvals. These approvals should be submitted to PDS staff. Additionally, applicants should continue work on civil construction (if necessary) to complete all inspections, as-builts, and project bonding.

Once a project is approved for final signed prints, the applicant will be contacted by PDS for any outstanding items that must be addressed before a project can be administratively. The applicant must obtain signatures from the surveyor, all parties with interest in the plat, and other certificates of approval from County departments. Payment of all taxes due for the calendar year and any other outstanding back-taxes must be made in full to the Snohomish County Treasurer prior to recording.

Submittal and resubmittal. Submittal of final plats are accepted at Additional reviews of projects must be resubmitted through (additional reviews beyond the second are subject to a standard resubmittal fee). Plats that were originally approved with any public road dedication or as a long plat will require onsite noticing of the final plat review and postcard notification to parties-of-record and property owners within proximity of the project site. Applicants must post notice signs issued by PDS staff on their property.

Checklists. Final Plat Submittal Checklist (short plats and long plats).