Status:
June 2025

Segment A includes a total of 12 miles of 42-inch diameter raw water pipeline, with 8.5 miles of pipeline within Thornton and the remainder in Adams County. Segment A of the project is generally located from 168th Avenue and Quebec Street to 88th Avenue and Colorado Boulevard where a connection will be made to the existing pipelines that deliver water to Thornton’s Wes Brown Water Treatment Plant (WBWTP).
The project includes two primary pipeline phases and additional work near the WBWTP.
- The Phase I pipeline starts at the intersection of E 168th Avenue and Quebec Street and continues south essentially along Quebec Street to E 120th Avenue.
- 14,216 linear feet of pipe has been installed in Phase I.
- The contractor has completed tunnels under 120th Avenue, 136th Avenue, 160th Avenue, and the Quebec Street crossing just north of 160th.
- Work in the upcoming months includes pipe installation in Quebec Street north of E 120th Avenue, the 168th Avenue crossing, the E-470 tunnel, and site restoration activities between 160th and 168th Avenues.
- The Phase II pipeline starts at the end of Phase I, just west of the intersection at 120th Ave and Quebec Street and continues south to the WBWTP near E 88th Avenue and Colorado Boulevard.
- 10,314 linear feet of pipe has been installed on Phase II.
- The contractor has completed the Old Riverdale and 104th Tunnels and installed pipe between 100th Avenue and Old Riverdale Road (ADCO Open Space).
- Work in upcoming months includes tunnel crossings at 100th Avenue, pipe installation between 100th and 104th Avenues and north of 112th Avenue / Old Riverdale, and site restoration activities between 100th and the Old Riverdale tunnel.
This segment of the project is scheduled to be complete in summer of 2026. Click on the image to the right to see the water pipeline route in Segment A.
View the City of Thornton’s current capital improvement projects map.
Please call the Thornton Water Project mainline at 720-977-6700 if you have any questions.