The Water System Plan (WSP) is a comprehensive evaluation of the city's water utility infrastructure system. Every 10 years this study is conducted to document existing infrastructure, projected water use demands, and regulatory requirements for a 20-year planning horizon.
Plan Update - May 2026
The city has been working to update the plan, and a draft is now available for review at the links below.
- Volume 1 - Water System Plan - 2026 DRAFT.pdf
- Volume 2 - Appendices - 2026 DRAFT.pdf
- Volume 3 - Interlocal Agreements - 2026 DRAFT.pdf
- Volume 4 - Water Engineering Standards - 2026 DRAFT.pdf
Highlights from the draft plan
After the robust analysis conducted for the plan update, two key findings reflect the success of water planning efforts and the critical work related to water services:
- With projects currently underway, the city has enough access to water and enough system capacity to serve the population for the next 20 years!
- The City is investing in infrastructure to improve system resiliency and should continue to make improvements that strengthen the system and provide for emergency water supply.
Service area and population growth
The current service area covers almost 37 square miles and includes the City of Bellevue, Yarrow and Hunts Point, Clyde Hill, Medina and parts of Kirkland and King County.
The service area population is currently over 160,000 people and is expected to grow almost 50% by 2044. Much of the anticipated growth is expected to occur in the Downtown, Bel-Red, and Wilburton neighborhoods.
Plan recommendations
A full summary of recommendations to improve and maintain the water system can be viewed in the Draft Plan. Below are a few highlights of the recommendations.
- Add water storage: Approximately seven million gallons (MG) of additional water storage will be needed to address growth. Most of this will be addressed with a six MG reservoir currently in design and scheduled to be completed by 2031.
- Assess pipe capacity: The city’s water main replacement program is addressing many of the pipe capacity needs. In the coming years, the city will evaluate if additional improvements are needed in the northeast and southwest areas of the city.
- Continue system modeling: The city’s computer model allows staff to simulate real-world conditions and determine the best ways to address system deficiencies. City staff will continue to perform flow testing to ensure accurate results.
- Develop emergency supply: The city has been working to develop emergency water wells and replace old pipes with stronger pipe materials. These efforts, along with regional coordination, should be continued as a key component to improving system resiliency.
Community Engagement
Community engagement is essential to shaping a water system plan that reflects the needs, priorities, and values of the people it serves. By listening to community input, we can make informed decisions about investments, sustainability, and long-term reliability. Stay tuned for upcoming opportunities this summer to learn more and share your voice. In the meantime, if you have questions or feedback that you would like to share regarding the water system, please email Senior Engineer Jim Grueber PE at jgrueber@bellevuewa.gov.
Previous Plan
The links below are to the plan that was last adopted by City Council in June 2016 and approved by the State Department of Health in January 2017.