Water Treatment Plant New Construction Project
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. More information on the Water System Study can be found at the below link.
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. Additional information on manganese can be found at the below link.
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. The picture below shows the property for construction of the water treatment plant.
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.
Times are subject to change.
- April 18, 2023 - Council approve Contract with recommended firm (completed)
- April 19, 2023 - Water Treatment Plant design begins (completed)
- Fall 2023 - Renderings due
- November 2023 - 60% plans due and specifications due
- February 2024 - 95% plans and specifications due
- February/March 2024 - Project bid and awarded
- 2024 to 2026 - Construction
- 2026 - Water treatment plant operational, treated water to residents
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 water treatment plant itself will cost an estimated $33,450,000 to design and construct.
Rates for Customers
The project will increase rates for residents, however, residents will see the benefits of safer and cleaner drinking water. 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.
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. Whether or not the City receives the federal funding, the project is moving forward. Below 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 are being adjusted based on the City receiving federal funding.
Northfield $40.09, Mankato $36.04, St. Peter $50.01, Fairmont $73.41, Northfield with federal funding $29.19
- Why does the City need to build a water treatment plant?
The city's water is above a Minnesota Department of Health guideline for manganese and is not recommended to be consumed by infants under 1 year old. The way to lower the level of manganese in the water is by providing treatment.
- What treatment will the City water provide?
The new water treatment plant will use gravity filtration with reverse osmosis to remove iron, manganese and hardness minerals or calcium and magnesium.
- It seems like the treatment plant is very expensive, were there other options studied to provide safe drinking water for all residents?
Yes, the city's consultant studied 3 treatment options:
- Gravity filtration
- Gravity filtration with reverse osmosis
- Gravity filtration with lime softening
- Why was gravity filtration with reverse osmosis selected as the best treatment option for the City?
Gravity filtration with reverse osmosis was selected because of the removal of manganese in the drinking water, the resiliency to future contaminants, the quality of water provided and the reduction of chlorides being added to drinking water through home water softeners thus resulting in lower levels of chlorides being discharged to the Cannon River.
- Did the City explore other treatment options, such as pressure filters, to remove iron and manganese?
Yes, however they were not recommended as options based on the scale of the drinking water system.
- Will the water be softened?
Yes, the water will be softened to roughly 90 milligrams per liter (mg/L) or what is considered moderately hard.
- Do I need to further soften my water?
The decision to further soften or not is up to residents; however, the City is recommending residents do not further soften their water.
- Will the water hardness level cause issues with my high efficient appliances or void their warranties?
No, the Minnesota Department of Health states that “If your water’s hardness is greater than 7 grains per gallon or 120mg/L, then you might need a water softener to ensure your appliances run well.” The City will provide water with roughly 90 mg/L or lower than the Minnesota Department of Health’s recommended softening level.
- When will the new water treatment plant be providing filtered and softened water to the Northfield properties?
The water treatment plant is expected to be operational in 2026.
- When the water treatment plant becomes operational, will it cause water chemistry issues?
When the water treatment plant first becomes operational, there will be a change in the water. City staff will conduct additional hydrant flushing to remove any built up discoloration in the water so that residents will be able to see the benefit of the new treated water as soon as possible.