South Hillsboro Pipeline Project

PLW_1.1 2017-06-12

Development of South Hillsboro, a 1,400-acre mixed-use community, requires coordination between multiple agencies and infrastructure projects. The Willamette Water Supply Program is coordinating with the City of Hillsboro, Washington County, and private developers to install the portion of the Willamette Water Supply pipeline that will serve the City of Hillsboro. To date, approximately 4,100 linear feet of the Willamette Water Supply pipeline has been installed in coordination with South Hillsboro road projects.

Pipeline construction began in the summer of 2020 on the southern section of the South Hillsboro Pipeline (PLW 1.3). The section of the pipeline under construction is approximately 10,700 feet in length, connecting on the north to the pipe that has already been installed through South Hillsboro. The PLW_1.3 pipeline alignment follows the future Cornelius Pass Road alignment south to Rosedale Road and then east along Rosedale Road to 209th Avenue. The pipeline will connect to the Tualatin Valley Water District system at the intersection of SW Farmington Road and 209 th Avenue. Construction of this segment is anticipated to be complete in 2022.

Construction of the final section of the South Hillsboro pipeline project – an approximately 3,800 linear foot segment between the Cornelius Pass Road and TV Highway intersection and Frances Street – is scheduled to begin in 2022. This segment of the pipeline is being constructed in partnership with Washington County’s Cornelius Pass Road widening project.

The coordinated construction of the pipeline and the Cornelius Pass Road improvements and extension saves money, reduces community and neighborhood impacts, and minimizes the need for multiple construction projects.

Project Updates

Project Update Emails Archive

Construction Updates


As summer is in full swing, our crews are being extra cautious about fire danger. Safety measures are in place whenever they are doing work that has a potential to create sparks. This includes having a fire extinguisher nearby and soaking an area with water.

When extremely hot weather is forecasted, the crews may adjust their schedule to start work earlier than usual and end before the heat of the day.


In late August and September, crews will be installing appurtenances, testing the pipe, and restoring the easement areas. At times, there may be lane closures and flaggers controlling traffic.


Crews are installing approximately 6,800 linear feet of 66-inch pipe along the future Cornelius Pass Road alignment. Each 50-foot piece of the 66-inch pipe weighs as much as 43,000 pounds – approximately the same weight as 12 compact cars.

Our Reliable Water

Program Timeline

Developing the new Willamette water source will take over a decade.

Willamette Water Supply Program

Willamette Water Supply Program