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Coordinated Water System Plan (CWSP)

In 1990, Island County adopted its Coordinated Water System Plan (CWSP). The purpose of the CWSP is to help the coordination of water systems within a Critical Water Supply Service Area (CWSSA) to ensure the critical resource is managed efficiently. The entire boundary of Island County is designated a CWSSA, so all water systems within Island County are subject to the CWSP. The CWSP acts as a regional supplement to each individual water system plan, and includes guidance for those water systems, including minimum design standards. The CWSP also contains the map of the official service area boundaries for each water system. Any modification of these service area boundaries must be done through an official amendment of the maps within the CWSP. This is done through the Water System Review (WSR) process.

If you have any questions about the Coordinated Water System Plan (CWSP) or the Water System Review (WSR) process, please contact Jonathan Lange, (360) 678-7821.


What is the Public Water System Coordination Act of 1977 & Critical Water Supply Service Areas?

In 1977, the Washington State legislature adopted the Public Water System Coordination Act because "an adequate supply of potable water for domestic, commercial, and industrial use is vital to the health and well-being of the people of the state," RCW 70.116.010. This required jurisdictions to evaluate the water resources and water systems within their boundaries to determine if there was a Critical Water Supply Service Area (CWSSA). In 1985, the entire boundary of Island County was identified as a CWSSA because of a:

  • Proliferation of small water systems;
  • Possible limitation of groundwater quantity available in Island County;
  • Lack of coordination between adjacent water utilities;
  • Water quality problems, such as salt water intrusion and iron/manganese content;
  • Operation and management of small water systems, including funding of improvements; and
  • Lack of consistency between water system planning and County land use policies.

Twenty-seven CWSSAs were declared in Washington State (click here for a map).

What is a Coordinated Water System Plan (CWSP)?

After a CWSSA is established, a CWSP must be developed. The CWSP is a "plan for public water systems within a critical water supply service area which identifies the present and future needs of the systems and sets forth means for meeting those needs in the most efficient manner possible,"  RCW 70.116.030(1). The CWSP also acts as a regional supplement to all water system plans within the CWSSA. The CWSP must have at a minimum:

a)   An assessment of related, adopted plans;
b)   An identification of future service areas and service area agreements;
c)   Area wide water system design standards, including fire flow performance standards;
d)   Procedures for authorizing new water systems in the critical water supply service area; and
e)   An assessment of potential joint-use or shared water system facilities and/or management programs.

How is a Coordinated Water System Plan (CWSP) developed and updated?

A CWSP is developed and updated by the Water Utility Coordinating Committee (WUCC). Per WAC 246-293-150, a WUCC is established by the Board of Island County Commissioners, and consist of at least three voting members that include:

a)   The County legislative authority within the declared area;
b)   The County planning agency having jurisdiction within the declared area;
c)   The health agency having jurisdiction within the declared area; and
d)   A water purveyor with over fifty services within the declared area.

All water purveyors within the CWSSA shall be notified and asked to participate in the development and updated of the CWSP. Currently, the Water Resource Advisory Committee (WRAC), which is a citizen's advisory committee on water resource management, is doing a high level review of the existing CWSP, in order to identify areas where the CWSP could be improved during a future update.


Island County's Coordinated Water System Plan (CWSP)

Click here to download Island County's entire CWSP (31.6 MB)

Volume I Volume II - Appendices
Section I – Summary Appendix A – Background Ordinances and Regulation
Section II – The Coordinated Water System Plan Process Appendix B – Individual Water System Plans
​Section III – Planning Data and Future Water Supply Needs Appendix C – Population and Demand Forecasts
​Section IV – Assessment of Existing Water Supply Systems Appendix D – Water System Data
​Section V – Water Use Efficiency ​Appendix E – Water Rights Tables
Section VI – County-Wide Water Supply Policies ​Appendix F – Service Area Agreements
Section VII – Regional Water Supply Plan Appendix G – Minimum Design Standards
​Section VIII – Plan Adoption ​ Appendix H – Regional Water Association Sample Formation Documents
Appendix I – Sample Intertie Agreement
​Appendix J – Sample Satellite Management Agreement
​ Appendix K – Groundwater Resource Analysis
​Appendix L – Salt Water Intrusion Policy for Public Water Systems
Appendix M – Water Importation Study


Links to Other Jurisdictions Coordinated Water System Plans

(For Reference Only)

Whatcom's CWSP (2016)
Snohomish's CWSP (2010)
Kitsap's CWSP (2005)

Pierce's CWSP (2001)

Vashon Island's CWSP (1990)