Thornton has resumed construction on a long-anticipated 70-mile water pipeline that will bring drinking water from Northern Colorado to its growing community, marking a major milestone after years of delays and legal disputes.
The pipeline, stretching from northwest of Fort Collins to Thornton, is one of the largest infrastructure projects underway in the state. The vision for the project began back in the 1980s, when Thornton city planners began purchasing land and water rights in anticipation of future shortages.
“It was a long process,” said Todd Barnes, spokesperson for the City of Thornton. “The residents of Thornton have been hearing about this for a long time. This is their future water supply.”
For years, however, that vision was stalled. Thornton faced opposition and lawsuits from Larimer County and groups concerned about the impact of water diversion on the Poudre River ecosystem. Those legal hurdles have now been cleared, allowing the project to move forward.
While the legal process played out, Thornton began laying sections of pipe in communities more open to the project, including Windsor. In 2021, crews installed several miles of pipe through Windsor to ensure housing developments and new infrastructure would not later be disrupted. For four years, that stretch of pipeline sat unused—unconnected at both ends.
“We had some housing developments up north that were going to come in. We put the pipe in knowing we would eventually be able to hook up with those,” Barnes explained.
With approvals now secured, Thornton is extending the pipeline from Windsor south to the city. Current work includes one of the most complex stages yet: boring a 900-foot tunnel beneath the busy E-470 tollway.
“This is the Thornton Water Pipeline segment A. Segment A runs from 88th up to 168th,” said Bill Renz, project manager for the pipeline. Standing at the site, Renz pointed to stacks of welded spiral steel pipes that will eventually connect to Thornton’s water treatment facilities.
“The unique challenge here is we are boring a hole under E-470. The bore is about 900 feet long,” Barnes said, noting the scale and difficulty of the work.
This isn’t the first time Thornton has had to take on technically demanding tasks. In 2021, crews successfully drilled under the Poudre River in Windsor to lay pipe as part of the same project.
If construction proceeds on schedule, the city expects the pipeline to be operational by 2028. Once complete, the project will secure water access for Thornton’s fast-growing population for decades to come.
“In this business, you don’t get a lot of opportunities to work on what people would consider generational infrastructure,” Renz said. “This is a huge deal for the citizens of Thornton and in general for Northern Colorado.”
The project represents more than just a pipeline—it is a lifeline for a city that foresaw its future needs decades ago and invested accordingly, despite the obstacles.
Originally reported by Dillon Thomas in CBS News.
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