Grabhorn Road closure

SW Grabhorn Road, between SW Tile Flat Road and SW Stonecreek Drive, will close April 5 for pipeline construction.
The road closure, planned for April 5 through July 5, will be in place 24-hours a day, seven days a week. Local access to properties on Grabhorn Road will be provided; through traffic will not be allowed. We recognize this closure is an inconvenience and we appreciate your patience. If you are traveling in the area, please use the suggested detour route and do not cut through the adjacent neighborhood. Please see the included detour map.


The Scholls Ferry Road Pipeline Project is a 7.0-mile section of the overall 30+ mile Willamette Water Supply System (WWSS) pipeline. To date, approximately half of the 7.0-mile section has been constructed. The remaining section, Grabhorn Road to Rosedale Road, will begin construction in Spring 2022 in conjunction with the South Beaverton Area Water Storage Tank. The joint construction project is being led by the Hoffman Fowler Construction Manager/General Contractor team. Construction will be coordinated to reduce the impacts on close by neighbors and the traveling public.

Scholls Ferry Area Pipeline (PLM_5.3)

Includes approximately 20,000 linear feet of 66-inch diameter, welded steel pipe. The pipeline alignment begins near the intersection of SW Tile Flat and SW Grabhorn Roads, where it will connect to the recently completed pipeline. The pipeline alignment follows SW Grabhorn Road north to the future water storage tanks at the intersection of SW Grabhorn and SW Stonecreek Drive. The pipeline alignment, then travels west and north on private property, crossing beneath Farmington Road where it will connect to the South Hillsboro Pipeline Project (PLW_1.0), which is currently under construction and is anticipated to be complete in fall 2022.

South Beaverton Area Water Storage Tank (RES_1.0)

A 15-million-gallon water storage tank will be built on property at the southeast corner of the SW Grabhorn Road and SW Stonecreek Drive intersection. Future construction of a second water tank is anticipated to be built on the site in 2035.

Construction Schedule

  • Water Storage Tank: 2022-2024
  • Pipeline Phase 1 (from the water storage tank site west & north to SW Rosedale Road): 2022 – 2023
  • Pipeline Phase 2 (from the water storage tank south to Tile Flat Road): 2023 – 2024

Construction Impacts

We recognize construction activities can be disruptive. There will be noise due to blasting of rock and construction equipment, and traffic delays and detours.

Rock Blasting: WWSP construction, waterline trench and water storage tank excavations will require blasting of rock. This is a common practice used to break large rocks into manageable sizes so that the rock can be removed by standard construction equipment. Micro-charges are detonated to break up the large rock that needs to be removed.  WWSP blasting will only occur during normal working hours (8 AM to 6 PM). Immediately before blasting occurs, the contractor will release a warning signal, like a whistle. If you would like advanced notice of the rock blasting schedule, please email or call the project hotline 503-941-4570 and leave your request, name, phone/text number and email address and how you would like to be notified.

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    Traffic Impacts: At times, there will be traffic delays, detours and road closures in order to install the pipeline across or beneath roads and during blasting. Flaggers will make sure traffic continues to move and will limit delays. Traffic delays are detours are expected on Koehler Road (summer/fall 2022), Green Slope Road (fall 2022) and Riggs Road (fall 2022). In 2023, sections of SW Grabhorn Road will be closed at times to through traffic (local access will be allowed). WWSP will provide property owners in these areas with more information before the work begins.

    Potential delays may also be needed for site clearing, construction traffic movement, safety near rock blasting and utility relocating.

    Completed Pipeline Construction

    The Willamette Water Supply Program team coordinated with public and private road improvement projects in the Roy Rogers, Scholls Ferry and Tile Flat Road areas to install the new water pipeline. Partnering on these road projects reduced community and neighborhood impacts by eliminating the need for multiple construction projects.

    The pipeline north of Beef Bend Road to Scholls Ferry Road (PLM_5.1) was a partnership with Washington County’s Roy Rogers Road widening project. Visit Washington County’s website for information about road improvements. Construction began in 2018 and is now complete.

    Construction of the pipeline from Scholls Ferry Road to Grabhorn Road (PLM_5.2) was coordinated with new residential development along SW Scholls Ferry and SW Tile Flat Roads. Construction began in 2019 and is now complete.

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