Water Treatment Plant New Construction Project

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The City is constructing a water treatment plant (WTP) to lower levels on manganese in drinking water to water consumers in Northfield. The project currently is in the design phase and construction will happen in 2024 and 2025. The project is funded in the capital plan.

Need for a water treatment plant

On April 5, 2022 the City Council accepted the Water System Study and its related recommendations.

Water System Study

Recommendations from the study

The study recommends constructing a water treatment plant that consisted of gravity filtration and reverse osmosis. A new water treatment plant will lower levels of manganese in the drinking water below the health-based guidance level of 100 micrograms per liter or less which can be harmful to infants under one year old. The water treatment plant will lower the level of manganese to ensure safe drinking water for all residents.

Manganese in drinking water

Softened water

As part of the water treatment plant, the water hardness will be reduced to roughly 90 micrograms per liter. This will make the water below the Minnesota Department of Health’s recommendation for needing to have a water softener in homes but you will still have the option to further soften your water.

The City recommends removing your in-home water softener. Removing in-home water softeners will reduce chlorides from entering the sewer system and being discharged into the Cannon River.

Residents who choose to remove their in-home water softener will see a break even or cost savings by having the City soften the water instead of themselves.

Additionally, the reverse osmosis or softening portion of the water treatment plant will provide resiliency by removing any future unknown contaminants in the drinking water.


The City is constructing the water treatment plant near its existing water tower located at 1353 Hall Avenue on land recently purchased by the City. As part of the water treatment plant construction, raw watermains will be extended to the site for treatment prior to entering the existing distribution system. Additionally, Jefferson Parkway will be extended adjacent to the water treatment plant as well as a new north-south residential street.

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View proposed site plan (PDF)


The landscaping concept plan will be finalized in the coming months to include specific planting varieties. The landscaping plan will follow the city’s Climate Action Plan (goal IN – 3.9 “Increase carbon sequestration through reforestation and enhancement of soil health on public lands through conversion of turf to native plantings and plant species that can tolerate a changing climate.”

The landscaping plan will also help minimize staff maintenance on site once the landscaping has established itself. 

The building will also have rooftop solar maximized to meet the city’s Climate Action Plan (goal IN 3.8 – Identify opportunities for on-site renewable installations) and to meet recommendations from the Water System Study to maximize rooftop solar and not construct ground mounted solar. Both the Climate Action Plan and the Water System Study involved community engagement in creating those documents.

Northfield Climate Action Plan (PDF)

Landscape concept rendering showing stormwater basins, trees, pollinator plantings, future buildouts

View landscape concept plan (PDF)


Times are subject to change.


The project is going to cost roughly $36,450,000 with the construction of the new water treatment plant and new roads that are being constructed for access to the property. The annual operation and maintenance costs for the water treatment plant are expected to increase by approximately $900,000.

Rates for customers

The project will increase rates for residents, however, residents will see the benefits of safer and cleaner drinking water. Additionally, residents will be able to remove their in-home water softeners and no longer have to bring salt into their home.

Water rates will increase by 20% for the next three years, then 15% for one year and 5% for the following years based on this project or roughly $15.00 per month for the average water user for 2022 rates versus 2026 rates. Wastewater, stormwater and garbage rates are not affected by the construction of the water treatment plant.

Federal funding

The City has applied for federal funding which the city’s project was approved as a project in 2022 and now is seeking the appropriations or funding by the federal government. 

Currently, the City has applied for Congressional-Directed Spending for fiscal year 2024 for $2,958,750. Staff will be seeking additional funding through Congressional-Directed Spending for both fiscal year 2025 and fiscal year 2026 each for $11,064,375. The total request will be for $25,087,500. 

Whether or not the City receives the federal funding, the project is moving forward. This is a graph showing the adjusted rates if the City does or does not receive federal funding in comparison to similar cities that soften the water. Rates were adjusted in 2022 and 2023 based on the City receiving federal funding.

WTP Projected Rates

Northfield $40.09, Mankato $36.04, St. Peter $50.01, Fairmont $73.41, Northfield with federal funding $29.19

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Bolton & Menk, Inc. proposal

Water System Study