Skip to main content

Conveyance System Improvement

The Conveyance System Improvement (CSI) Program looks at ways to improve the King County wastewater conveyance system and address public health concerns, while ensuring that the system has sufficient capacity to respond to regional growth.

King County’s regional conveyance facilities are located throughout the County’s wastewater service area and include over 390 miles of regional conveyance pipes, 47 pump stations, and 25 regulator stations.

Next CSI Program Update

The CSI Program Update verifies, adjusts, and identifies new CSI projects needed for increasing capacity in the conveyance system to accommodate future flow from both the growth in population and infiltration and inflow (I/I). King County code requires periodic updates. The next update is planned to be complete in 2027. In preparation for that update, WTD staff are initiating data collection and processing activities in 2023.

To read about the current program update from 2017, please see 2017 CSI Program Update.

Steps taken for the conveyance system improvement program update: update planning assumptions, complete regional conveyance system needs assessment, develop conceptual projects and cost estimates, and prioritize projects.

Program updates

Planning the regional conveyance system is an ongoing task at King County. 

Flow monitoring

Learn how monitoring wastewater flows is an important component of the CSI Program.