3D rendering of planned McCarrons Treatment Plant from aerial viewpoint
3D rendering of planned McCarrons Treatment Plant from aerial viewpoint

McCarrons Treatment Plant Improvements

The McCarrons drinking water treatment plant has a century-long history of providing reliable, high-quality drinking water to the residents of Saint Paul and neighboring communities. As we look toward the future, we are committed to making significant improvements to ensure that our water supply continues to meet the highest quality standards and that our infrastructure remains robust and reliable.

The McCarrons Water Treatment Plant is one of only 31 facilities in the nation to have received the prestigious Presidents' Award for Water Treatment from the Partnership for Safe Water. This recognition highlights our commitment to delivering the best possible water quality for our customers.


Our primary focus at SPRWS is to ensure the continued supply of clean and safe water to our community. The objectives of the McCarron's Water Treatment Plant improvement project align with this:

Replace Aging Infrastructure

Heavy equipment in front of debris from demolition of McCarrons treatment plant

The majority of the current facilities at the treatment plant were built between 1920 and 1950. While they continue to serve us well, their reliability is reduced with each passing year. It's crucial for public health and safety that we replace these aging structures before they fail.

Cost Efficiency and Rate Control

We recognize the importance of being stewards of our community's resources, both in terms of water and finances. By starting this project when interest rates were low, we can carry out the improvements in a cost-efficient manner. This approach helps us avoid the much higher costs associated with emergency replacements, reducing the need for significant rate increases. All project decisions have been made with a clear focus on providing the best long-term value for SPRWS customers.

Secure Future for Water Resources

This project is about meeting the needs of today and securing the future of water resources for our community. The upgrades are investments in infrastructure that all 450,000 of our customers can rely on for generations to come. With these improvements, we're ensuring excellent quality drinking water for you and your family now and into the future.


This project involves improvements to our treatment processes and infrastructure. There's a focus on ensuring reliability, enhancing efficiency, and incorporating advanced technologies. Here's an overview of our project's key components:

Embracing Advanced Technologies

The project covers improvements to all the pre-filtration stages of the treatment process. We're implementing more modern, efficient variations of the processes and technologies that have served us well for decades. This includes enhancements for removing water hardness, enhancing water clarity, adjusting pH, and eliminating contaminants.

Introducing Ozonation

Cutaway profile of rendering of ozone and recarbonation basins in new McCarrons treatment plant design

In a significant advancement, we're integrating ozonation into our water treatment process. Employed in water treatment facilities around the world, ozonation comes with several benefits. It reduces the possibility of taste and odor issues in the water and aids in removing contaminants of emerging concern—certain pollutants whose health effects are currently being studied.

Out with the Old, In with the New

We're carrying out demolition work to remove old, obsolete infrastructure. This helps by reducing maintenance costs, making room for new components, and freeing up space for future additions. SPRWS staff are collaborating with the Minnesota State Historic Preservation Office and local historical societies to document and honor the 100+ year history of the existing facility.



Tree Removals and Sitework: Early 2022 (Complete)

In early 2022, the project began with necessary tree removals and preparatory sitework. This step helped us establish a safe and efficient working area, ensuring the following stages go as smoothly as possible.


Stage 1 Demolition: Mid-Late 2022 (Complete)

Following the initial sitework, the mid to late months of 2022 were dedicated to Stage 1 Demolition. During this time, we removed obsolete infrastructure to make way for new facilities.


Stage 1 Construction: October 2022 - August 2025

The project's largest phase is the construction of the new facilities, spanning from October 2022 to August 2025, . Initial construction will focus on building foundations, exterior walls, and roofing. Once complete the work will shift indoors. Indoor work includes installing mechanical equipment, chemical storage tanks, electrical infrastructure, plumbing, lighting, etc. Stage 1 construction includes everything needed to make the new facility operational.


Final Testing of New Processes: August 2025

We will undertake a meticulous testing phase for all the new processes. This step ensures operational efficiency, safety, and compliance with all regulations. After testing is complete, the new facility will begin to produce water for all SPRWS customers.


Stage 2 Demolition: September 2025 - June 2026

The second stage of demolition will take place from September 2025 to June 2026. Once the new facility is producing water, a significant amount of old infrastructure will be obsolete. This stage of demolition will remove the obsolete infrastructure and prepare the site for final restoration and landscaping.


Stage 2 Construction: November 2025 - July 2026

Stage two demolition will free up space on the campus for more construction. During stage 2 construction we will build a new water quality laboratory, finish work on the new facilities, and landscape.


Last Edited: June 4, 2024