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Westminster Blvd. Drinking Water Project

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The new drinking water facility design is underway

What’s Happening Now? Join our Open House on October 5! 

graphic image announcing the Open House - decorative

Join us for an open house about the Westminster Boulevard Drinking Water Project. The project recently reached two important milestones: 

Come voice your thoughts about the EA or the project. 

Thursday, October 5
Open house: 6-8 p.m.
Presentation, Q&A and public comment*: 7-8 p.m.

Longs Peak Room
City Park Recreation Center
10455 Sheridan Boulevard
Westminster, CO 80020

Can’t make it? Learn more and provide comments online anytime between September 12 and October 12 at WestminsterDrinkingWaterFacility.com

Draft Environmental Assessment Comment Period

The draft environmental assessment report (EA) for the Westminster Boulevard Drinking Water Project is now available for review and the community’s feedback. 

View the Environmental Assessment

View the Project Needs Assessment

Comments on the draft EA will be accepted between September 12 and October 12. Comments and questions will be officially reflected and responded to in the final EA.

How to submit an EA public comment:

  • Fill out a comment card at the October 5 in-person open house.
  • Speak with a stenographer at the October 5 in-person open house. The stenographer will be present to capture your feedback verbally for up to three minutes per turn.
  • Submit a comment through the virtual open house platform at WestminsterDrinkingWaterFacility.com.
  • Email us at: waterfacilityproject@westminsterco.gov. Please include "EA Comment" in the subject line.
  • Call us at (720) 464-3435 and be sure to state that this is an “EA Comment” in the message.
  • Mail us a letter: 

Westminster Boulevard Drinking Water Project
1670 Broadway, Ste. 3400
Denver, Colorado 80202

*A note about questions and comments on October 5: You will need to register for a time slot upon arrival if you wish to ask questions following the public presentation. While we welcome comments and questions, it is separate from the EA's public comment process. To submit a formal public comment on the draft EA, please see “How to submit an EA public comment” above. 

Sign up for updates

There will be opportunities this fall to learn more about the project and share your feedback with us. Please sign up for our email newsletter to get the latest information on design progress, the environmental assessment process, open houses, engagement opportunities, and project impacts. 

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Project Summary

The City of Westminster is committed to providing affordable, high-quality water services. Semper and Northwest water treatment facilities currently supply more than nine billion gallons of clean and safe drinking water annually through over 500 miles of pipes to our residents and businesses.

The 54-year-old Semper Water Treatment Facility is nearing the end of its useful life and will soon need to be replaced. In 2015, the City began planning for a new water treatment facility to replace Semper.  Over the past two years, under City Council’s guidance, the City reevaluated the project and considered different options for the facility to better balance the community’s need for clean, safe, and affordable water after the community raised concerns about affordability.

The reevaluation focused on rightsizing the facility and associated infrastructure, which originally had an inflation-adjusted cost of over $300 million. As a thorough reevaluation, City Staff was able to reduce project cost by over $100 million, and City Council capped future rate adjustments to no more than 4.5% over the next decade. The approved Westminster Boulevard Drinking Water Project is a cost-effective, affordable solution with the flexibility to:

  • Replace aging infrastructure and expand if needed.
  • Respond to future state and federal clean water regulations.
  • Build additional treatment processes to respond to potential future wildfire contamination and emerging contaminants. 

Preliminary estimates for constructing the new facility are upwards of $200 million. This preliminary cost estimate ranges from -15% to +30%.  As design progresses, the estimate will become more certain and will be adjusted to market conditions and prevailing construction valuation. 

The new facility will ensure the community continues to have clean, safe, and affordable drinking water for generations to come.

Map of Drinking Water Facility location
Click here for an ADA accessible PDF of the above photo

On April 24, 2023, City Council adopted Resolution 13, directing City staff to pursue the construction of a water treatment facility along Westminster Boulevard between 98th and 104th avenues. The project is currently in the planning, permitting, and design phase, with an expected 2028 completion date.




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 current water treatment regulations were issued and modern 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 water treatment facility will eventually replace Semper as it is phased out in the next two decades.

The facility site will have sufficient space to expand as water treatment processes and infrastructure are due for replacement. This phased approach is a financially responsible way to maintain and replace Westminster’s drinking water treatment infrastructure and will allow the City to keep the newer portions of Semper operational for the duration of its useable life. 

Over the past few years, under City Council’s guidance, the City reevaluated options for Westminster’s new water treatment facility to better balance the need for clean, safe, and affordable water. This reevaluation focused on rightsizing the facility and associated infrastructure, which originally had an inflation-adjusted cost of over $300 million. Reducing the size of the facility and leaving room for future expansion reduces the projected cost, potentially saving ratepayers more than $100 million. The new facility will allow aging parts of Semper to be retired while continuing to use viable components as long as reasonable to maximize the value of those investments. This will allow a phased approach to replacing Semper.

The near- and long-term fiscal plan for the water utility currently includes up to 4.5% rate adjustments each year. 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. 
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.
Please do not hesitate to reach out to the project team, which can be reached by email at waterfacilityproject@cityofwestminster.us or by phone at (720) 464-3435. Thank you for your patience while we invest in our community!
What is 30%, 60% and 90% design? 

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. 

Construction Notification and Community Input

Residents of Hyland Village and Waverly Acres and businesses near the new facility site will be notified via door hanger and/or postcard about potential construction-related impacts to their communities as well as additional opportunities to provide feedback on the project.

We understand that this construction would impact residents as well as users of our open space. We will make every effort to ensure construction impacts and project updates are communicated early and often. Sign up to receive project emails using the form above, or follow the City on Facebook, Twitter, or Nextdoor for regular updates. Updates will be made to this page as new information or opportunities become available. 

Associated Projects

The City is also working in conjunction with the following utility projects:

Water Supply Line 

A two-mile, 36-inch-wide waterline would transport untreated water from Standley Lake to the new treatment facility. The new water supply line would connect to the existing Standley Lake waterlines and would connect to the facility at the project site’s southern boundary.

Finished Waterline

A 30-inch-wide finished waterline would deliver clean, safe, and affordable drinking water from the facility to our community. The finished water pipeline would extend approximately one-third of a mile from the facility’s eastern boundary and connect to an existing water main.

Sewer Line

A 650-foot-long sewer line would carry domestic wastewater from the facility to an existing sewer line located east of the project site. 

Map of water supply line

Click here for an ADA accessible PDF of the above map

April 24, 2023 - City Council selection of Option 4, Constructing a new right-sized facility on the Westminster Boulevard site

February 6, 2023

January 23, 2023

Jul 11, 2022

May 23, 2022

April 25, 2022

April 11, 2022

March 28, 2022; pt. 2

February 28, 2022

January 10, 2022

December 21, 2021

  • Legal notice - posted in The Denver Post on September 4, 2023
  • Postcard - mailed the week of September 18, 2023

Project Funding

The City anticipates that the total funding needed will be a combination of the following:

  • Grants
  • Cash on hand
  • Municipal revenue bonds
  • Drinking Water Revolving Fund (DWRF) financing from the State of Colorado
  • Water Infrastructure Finance and Innovation Act (WIFIA) financing from the federal government

The City is currently researching the best financial strategy and appropriate level of funding from each resource available to ensure the most cost-effective terms for design and construction.

Environmental Assessment

An environmental assessment (EA) is being prepared to analyze the proposed facility’s potential impacts on the physical, biological, and human environment. The EA will evaluate direct impacts of proposed improvements within the project area, which corresponds to the facility site and waterline alignments. The EA study area for secondary and cumulative impacts includes the City’s water service area. Findings from the EA will be presented at a public open house in the fall of 2023 and the community will have an opportunity to submit feedback. 

Sign up for our project newsletter here!

What does a new treatment plant mean for my water rates? 

City Council incorporated the cost of the new water treatment plant when it approved the historic rate reductions last year. In order to provide immediate relief to rate payers, City Council adopted lower rates within the current three-tiered structure and increased the volumes allotted within each of those tiers in 2022. This significant rate reduction followed previous 10% water rate increases in both 2019 and 2020.  

City Council directed staff to better balance the need to maintain affordable water rates, while maintaining the City’s water system and ensuring the financial health of the water utility into the future.    

After extensive financial modeling, City Council adopted a 4.0% rate increase for 2023 and capped rate increases to no more than 4.5% for the next decade to balance the budget. These moderate rate increases over time support the defined 2023-2027 Capital Improvement Program including the right-sized water treatment plant while ensuring clean, safe, and affordable water for generations to come.