Water System Plan

Seattle Public Utilities provides reliable, high-quality drinking water to 1.6 million people who live in Seattle, King County and portions of southern Snohomish County. Thoughtful planning and strategic investment in our drinking water supplies and infrastructure will help ensure our region has enough water to meet the needs of our customers for decades.

To plan for long-term needs and meet regulatory requirements, Seattle Public Utilities regularly updates its Water System Plan. The 2019 Water System Plan is the latest update. It describes near- and long-term plans for the regional water system. It also focuses on updates to the water system and programs since the 2013 Water System Plan was completed.

The Plan describes how Seattle Public Utilities:

  • meets current and future water demands,
  • ensures high-quality drinking water,
  • enhances system reliability and resiliency, and
  • cost-effectively invests in and maintains the water system.

2019 Plan Review and Adoption

SPU released the Public Review Draft of the 2019 Water System Plan on March 12, 2018. The plan, which contains changes to address the comments received on the draft plan from the public, was reviewed by Mayor Jenny Durkan and the Seattle City Council. In October 2018, it was adopted by City Ordinance 125687 (pdf).

The Water System Plan was approved by King County and the Washington Department of Health in 2019.

View Final Water System Plan, August 2019

Summary - 2019 Water System Plan (PDF)

Volume 1 - 2019 Water System Plan (PDF)
Includes: Chapter 1 - Introduction, Chapter 2 - Water Resources, Chapter 3 - Water Quality and Treatment, Chapter 4 - Water Transmission System, Chapter 5 - Water Distribution System, Chapter 6 - Capital Improvement Budget, and Chapter 7 - Financial Program

Volume 2 - 2019 Water System Plan - Appendices - See below for links to Part A, B, C and D.

  • Part A - Water Resources (PDF)
    Includes: A-1 Official Yield Estimate and Long-Range Water Demand Forecast, A-2 Water Right Self-Assessment, A-3 Groundwater Elevations at Seattle Well Fields, A-4 Monthly Production Data by Source, A-5 Water Reclamation Evaluation Checklist, and A-6 Water Shortage Contingency Plan
  • Part B - Water System Inventories (PDF)
    Includes: B-1 Water Facilities Inventory Form, B-2 Water System Management and Operator Certification, B-3 Water Treatment Chemicals, and B-4 Asset Inventories.
  • Part C - Policies, Procedures and Standards (PDF)
    Includes: C-1 Comprehensive Water Quality Monitoring Summary, C-2 Design Standards and Guidelines - Water Infrastructure, C-3 Design Standards and Guidelines - Plan Review, C-4 Standard, Connection and Administrative Charges - Water, C-5 Water Rates, C-6 Water Availability Certificates, and C-7 Water Service Within the Direct Service Area
  • Part D - Miscellaneous (28mb PDF)
    Includes: D-1 Distribution System Analyses (A. Fire Flow Analysis, B. High Pressure Areas, C. Pump Stations and Standby Storage Allocation Tables), D-2 Capital Facilities Plan, D-3 Land Use and Zoning Maps, and D-4 Plan Content and Consistency Review Checklists

Archived Plans



Contact Information

Alex Chen
Deputy Director for Water Line of Business and Utility O&M
(206) 684-7414

Public Utilities

Andrew Lee, General Manager and CEO
Address: 700 5th Avenue, Suite 4900, Seattle, WA, 98104
Mailing Address: PO Box 34018, Seattle, WA, 98124-5177
Phone: (206) 684-3000

Newsletter Updates


Sign up for the latest updates from Public Utilities

Seattle Public Utilities (SPU) is comprised of three major direct-service providing utilities: the Water Utility, the Drainage and Wastewater Utility, and the Solid Waste Utility.