City of Boulder Reaches Milestone on its Main Sewer Improvements Project

The City of Boulder has completed the largest phase of its Main Sewer Improvements (MSI) Project, marking a significant step towards enhancing the city’s wastewater collection system’s resilience. This bond funded, $46-million phase included construction of a parallel pipeline from Valmont Road and Butte Mill Road to the Water Resource Recovery Facility (WRRF), located near 75th Street and Jay Road, as well as new pipelines to better serve the Gunbarrel community.

The MSI Project is one of the most critical infrastructure projects the city has undertaken in decades. The upgraded system conveys the majority of the city’s wastewater to the WRRF and improves operation and reliability. Completion of this phase increases flood resilience and reduces the risk of sewer overflows and backups during extreme weather.

The original sewer line was installed in 1968 and has operated during several floods, including one in 1969 and the Front Range flood of 2013. When floods impact our community, aging infrastructure has a higher potential to fail, possibly leading to environmental impacts. The new parallel pipeline will help prevent future floods of this level from impacting Boulder Creek.

This phase of the project also improved the sanitary sewer service to the majority of the Gunbarrel community by replacing the main pipeline that serves this area. The new system was built with multiple, smaller lines to provide better service to that area.

The final phase of the project is planned to begin in 2029 and will rehabilitate the remaining portion of the original sewer line from 61st Street to the WRRF, as well as a portion near 55th Street and Valmont Road. Learn more about the project on the city’s website.