Frequently Asked Questions

Westminster’s two drinking water treatment facilities, Semper and Northwest, provide water to the residents and businesses of Westminster, Federal Heights, and customers in unincorporated Jefferson and Adams counties. Semper provides drinking water for 75% of the City’s water demand and was built over 50 years ago, before modern water treatment regulations and technologies were developed. Northwest, built in 2001, has more modern water treatment technologies than Semper, and provides drinking water for 25% of the City’s water demand.  

The new facility will allow a controlled phase-out of the aging Semper facility. 

Continuing to operate Semper increases the risk of failure that could abruptly and severely limit the City’s ability to meet demand for drinking water Semper’s major systems are at or near the end of its service life. These systems include mechanical, electrical, structural, and piping systems. Options to renovate or rebuild Semper on site were evaluated, and building a new replacement facility at a different location was determined to be the most cost effective. The Westminster Boulevard site will have sufficient space to expand as water treatment processes and infrastructure to meet additional need and future drinking water regulations. This phased approach is a financially responsible way to maintain and replace Westminster’s drinking water treatment infrastructure and allow newer portions of Semper to remain operational for the duration of its useable life.

The first phase of the project will build a water treatment facility that produces 14.7 million gallons per day. This is adequate to treat current water demand and will allow the oldest parts of Semper to be taken offline. The first phase is anticipated to be built by the second half of 2028.   

While a second phase has been considered, it would depend on future water demand. 

The current estimate for constructing the new facility is approximately $200 million.  A Guaranteed Maximum Price contract will be presented to City Council in September 2025 prior to the start of construction.

The near- and long-term fiscal plan for the water utility currently includes annual rate adjustments of up to 4.5%. These adjustments support the operations and maintenance of the system, debt service obligations, and the defined 2024-2028 Capital Improvement Plan. This plan includes a new water treatment facility and other important repair and replacement infrastructure projects to ensure clean, safe, and affordable drinking water for generations to come.  

The 2.71 acres of open space were originally acquired as part of a larger land purchase for the construction of the Westminster Boulevard bridge and roadway project. It was determined the remaining land was not needed after roadway construction was completed, and it was redesignated as open space in 2009. It is city land and can be used for a public purpose in the future. Should the property be utilized for a public purpose other than open space, the open space acquisition fund will be reimbursed pursuant to the Westminster Municipal Code. 

We continue to explore what the new facility will look like. We will work closely with a community advisory team and provide the community with opportunities to share opinions during future online and in-person open houses. 

Several consultants are part of the project team: 

• PCL: Drinking water facility construction manager 
• CDM Smith: Drinking water facility design 
• Olsson: Environmental assessment 
• Burns and McDonnell: Water supply line design 
• HDR: Community outreach and communications, site selection, and modeling 
• Hazen: Drinking water facility process design 

After the City identified the need for a new drinking water facility, a site selection alternatives analysis was conducted to evaluate sites suitable for the construction of a new facility. The site selection process identified more than 50 sites for initial consideration. The initial site list was narrowed to nine using three categories of evaluation criteria:  

• Community 
• Engineering 
• Site characteristics

The next phase of the process further reduced the list to three recommended sites. After further consideration, the site at 98th Avenue and Westminster Boulevard was selected.

The new facility is not anticipated to have any strong odors associated with it because it is an indoor facility dedicated to treating drinking water. It is not a wastewater facility.  

The dewatering basins on the north side of the property are not expected to generate any sulfur odors during normal operations. The solids that accumulate in the basins will be removed periodically, usually after a freeze/thaw, draining/drying cycle over the winter. 

The building heights will range from 11.3 to 49.4 feet tall with an average height of 23.8 feet. The tallest building is the two-story process building. The water storage tank is designed to be on the ground, not an elevated water tower. 

The finished waterline is sized to exceed the water treatment capacity for phase 1. An additional finished waterline will be built if new water treatment trains come online in the future. This will help create reliability in the water system and make the system more dependable in the event of water main breaks or other issues that can arise unexpectedly.  

There will be dewatering basins on the northwest area of the property that will be filled and emptied on a cycle. Mosquito problems are not anticipated, but they will be mitigated if they occur. 

Common milestones for construction projects are 30%, 60%, and 90% design. These indicate the level of design that has been completed to that point and are often opportunities for public or community input.   

• 30% design – Very high-level design with major project elements defined. The project team is determining any fatal flaws, defining the scope of the project, and refining the cost estimate.   
• 60% design – Designs of major project components are completed and refined following input from the 30% milestone. The design team confirms that the plans and specifications will meet project objectives.   
• 90% design – Details and concepts are refined following input from the 60% milestone. This is often considered final design and all that usually remains is ensuring permits are in place prior to construction beginning.

The requirement to carry out an environmental assessment (EA) is necessary when acquiring federal funding for a project, and it needs to be initiated early in the process to stay on track with the overall project schedule. Initially, the City planned to pursue state and federal funding to make the best financial decisions for ratepayers.   

After a comprehensive financial analysis was completed, it was determined that funding the project through bond issues would be the most fiscally responsible option. Because federal funding will not be used for the project, the EA is no longer required. 

However, the City is still committed to implementing best management practices that protect wildlife and our natural resources, as it would have under the EA review. Throughout the project, the City will coordinate with Colorado Parks and Wildlife (CPW) to protect wildlife and associated habitat to ensure the project complies with CPW guidelines.