Stormwater Design Manual Update

 1st Draft - Design Manual

Kitsap County Stormwater Design Manual

(1st draft manual - complete) 

Summary of changes to

Kitsap County's Stormwater Design Manual

(2016 to 2020 Public Review Draft)

First draft comment period open until April 20, 2020

How can I submit comments about these amendments?

Written comments on the first draft proposal are due April 17, 2020 and may inform additional refinements to the proposed amendments, staff report, as well as the SEPA Determination (SEPA - State Environmental Policy Act).  Written comments on the first draft can be submitted: 

  • Emailed to Scott Diener at:
  • Mailed to Kitsap County DCD, 614 Division Street, MS-36, Port Orchard, WA 98366;
  • Dropped off at the Permit Center on the 2nd Floor at 619 Division Street, Port Orchard;
  • Submitted during the Planning Commission public hearing
  • Submitted using our Online Comment form

After review of all comments submitted on the first draft proposal, revisions, where appropriate, my be made and a second draft will be prepared.  This second draft will then move forward to the Kitsap County Planning Commission review and recommendation process.

Kitsap County Planning Commission

Oral and written testimony on a second draft may also be made to the Kitsap County Planning Commission during their public hearing tentatively scheduled for June 16, 2020.  Please visit this project website for updates and changes to the schedule.

Tips for preparing comments

  • Organize your comments so that general comments and comments regarding particular amendments can be easily distinguished.
  • Be as concise and clear as possible.
  • Explain how the amendment will benefit or affect you.
  • If you plan to provide oral testimony at a public hearing, submitting a written version at the hearing can be very helpful. Please note that oral testimony may be limited to 3 minutes per person/group to ensure everyone wishing to testify can be heard.
  • Including contact information is not required but is very helpful if additional information or clarification regarding your comment is needed.
  • Written comments and oral testimony at public hearings are the only ways for your comments to be part of the official record.

Click the banner below to comment using our on-line comment form:


In 2019, Ecology revised its stormwater design manual for Western Washington communities.  As such, Kitsap County is mandated to update it’s Stormwater Design Manual and relevant development codes for consistency. Kitsap County Departments of Public Works and Community Development have collaboratively embarked on a review and update process, with the assistance of a consulting firm.

Scope of Work

In April 2019, Herrera Environmental Consultants (Herrera) was contracted by Kitsap County to update the Kitsap County Stormwater Design Manual (SDM), develop an online version of the SDM, conduct focused review of the Kitsap County Code (KCC), and assist with any necessary revisions to the KCC.  The revised manual and any code changes will not be effective until January 1, 2021, or later if the Board determines a later date would be beneficial. 

Tentative Schedule

​Important Meeting dates and Materials

All the information listed below is tentative and subject to change.

​May 19, 2020
​Planning Commission Work-Study Briefing

​June 2, 2020
​Planning Commission Work Study Briefing (if needed)

​June 16, 2020
​Planning Commission Public Hearing

​July 7, 2020
​Planning Commission Deliberation and Findings of Fact

​July 15, 2020
​Board of County Commissioners Work Study Briefing

​July 27, 2020
​Board of County Commissioners Public Hearing

​August 5, 2020
​Board of County Commissioners Work Study Deliberation

​August 10, 2020
​Board of County Commissioners Ordinance Adoption

​January 1, 2021
​Ordinance Effective Date


State Resources:

Executive Summary of the 2019 Revisions

The Stormwater Management Manual for Western Washington (SWMMWW) provides guidance on the measures necessary to control the quantity and quality of stormwater. Local municipalities use this manual to set stormwater requirements for new development and redevelopment projects. Land developers and development engineers use this manual to design permanent stormwater control plans, create construction stormwater pollution prevention plans, and determine stormwater infrastructure. Businesses use this manual to help design their stormwater pollution prevention plans.

The development and administration of the Clean Water Act National Pollutant Discharge Elimination System (NPDES) municipal stormwater permits in Washington.

This document gives a brief summary of changes.  Appendix 1 contains the development regulations starting at page 84, ending at page 90.

Ecology has provided the crosswalk below to help you identify where content has been moved and/or renamed between the 2014 and 2019 manuals. Note that during the 2019 update some sections were merged together and/or edited for clarity. Therefore, you may not find the exact language from the 2014 manual in the linked sections of the 2019 manual indicated below. The links below will lead you to where the updated content is contained in the 2019 manual, providing updated guidance on the topic from the 2014 manual.


As part of the United States Clean Water Act and National Pollutant Discharge Elimination System (NPDES) permit program, Kitsap County is required to develop and implement a stormwater management program.  This program is intended to reduce discharge of pollutants to the maximum extent practicable and protect water quality. The Washington State Department of Ecology is the responsible agency for permit issuance to local jurisdictions.

Kitsap County is considered a Phase II NPDES permit jurisdiction and is located within census-defined urbanized areas and includes Urban Growth Areas defined by the Washington State Growth Management Act. As a Phase II jurisdiction, stormwater runoff and associated codes must comply with Ecology's rules to prevent and control the impacts of stormwater runoff from new development, redevelopment and construction activities.

Kitsap County's Title 12 and Stormwater Design Manual provides guidance and standards in stormwater management planning and design for development.

Additionally, in 2009,  the Kitsap County Board of County Commissioners approved Resolution No 134-2016 "Water as a Resource" policy.  This policy, in addition to requirements noted above, provide guiding principles to stormwater asset management, implementing development codes, public outreach and reporting needs.