Water quality 101: What every Minnesota homeowner should know
Water quality and water characteristics can affect both household plumbing and appliances.
Water properties vary by location and the source of the water piped into your home. Homes connected to municipal systems and homes connected to private wells often have different water characteristics.
The type of treatment system used in a home depends on the specific water issues present. These may include hardness, taste and odor, iron or manganese staining, sediment, chlorine, arsenic, nitrates, bacteria or other contaminants. Common water treatment systems include water softeners, whole-house filtration and point-of-use filtration.
CenterPoint Energy’s Home Service Plus® (HSP), Minnesota's largest provider of major appliance repair, systems maintenance and replacement services is a service provider based in Minnesota that understands local water conditions.
HSP can install residential water treatment systems to address common water quality issues . This guide will explain what softeners and filtration systems do (including advanced filtration such as reverse osmosis) and how to determine what your home may need.
Understanding your water source: Municipal water vs. private well water
Most Minnesota homes are connected to municipal water systems and receive a monthly utility bill from the local water company. The fees included in your water bill are generally used to fund the water treatment, equipment maintenance, testing, infrastructure maintenance and other standards that help your water meet the Environmental Protection Agency’s (EPA)
Safe Drinking Water Act standards, in addition to any state or local standards.
Minnesota benefits from one of the highest-performing public water supply programs in the country–over 97% of the state’s 6,585 public water systems met all federal health-based standards in 2024,
according to the Minnesota Department of Health's annual report. Municipal water systems may use disinfectants such as chlorine or chloramine to kill microbes in the distribution system. Disinfectants can also cause issues with taste or odors in your water.
Municipal water treatment also does not completely eradicate the minerals that may contribute to water hardness. Some naturally occurring minerals in water, such as calcium and magnesium, are considered beneficial, but they can still contribute to hardness and scale buildup.
In contrast,
roughly 20% of Minnesotans–more than 1.1 million people–get their drinking water from private water wells. Homeowners with private water wells are responsible for the safety and health standards of their own water, as government agencies don’t monitor privately-owned wells. Contaminants in wells, as in natural water sources may range from minerals such as calcium and magnesium that cause hard water, to hazardous elements such as coliform bacteria, nitrates and low levels of arsenic.
The Minnesota Department of Health (MDH)
recommends privately-owned wells undergo yearly well testing for coliform bacteria and nitrates, as well as testing for manganese, lead and arsenic.
Hard water in Minnesota
Hard water can be caused by elevated levels of minerals in water, primarily calcium and magnesium. As Minnesota’s groundwater supply flows through the mineral-rich glacier deposits of this region–layers of limestone, dolomite and calcium-rich till–the magnesium and calcium in them dissolve and enter, which are a source of the state’s water supply.
And when the water is heated, like in a water heater, the minerals inside the water precipitate and drop out as carbonate scale. Over time, that scale can build up on the heating element or tank bottom, reducing efficiency and shortening lifespan. Wherever the hard water evaporates, like on a shower door, it leaves behind the minerals. And when it’s used with soap, the calcium and magnesium react with the soap, preventing it from dissolving properly and leaving clothes stiff and skin dry.
That’s where a water softener comes in…
What does a water softener do?
| Calcium | Bacteria |
| Manganese | Heavy metals such as arsenic |
| Low levels of ferrous (dissolved) iron | Chlorine taste |
Installed at the point where your water enters your home, a whole house water softener addresses the minerals that make water hard, but it does not purify water or affect its safety. Signs you may need a softener include:
- white crust on faucets
- dry skin and hair
- appliances failing early; and
- soap not lathering.
The softener can help protect your plumbing, water heater, dishwasher and washing machine by preventing scale buildup, while giving water a better feel on skin and hair and making cleaning more efficient.
How is water filtration different?
Unlike a softener, a water filter does remove contaminants from your water, either by physically blocking them from getting through, using chemical adsorption to pull contaminants out or a combination of the two. Some systems combine filtration with softening, but softening is not a standard feature of filtration.
Contaminants that filters can typically remove include:
- chlorine/chloramine
- iron & manganese
- hydrogen sulfide (rotten egg odor)
- sediment.
Advanced filtration systems may also be able to remove contaminants such as lead, cysts, PFAS/PFOS and other “forever chemicals.”
Filtration vs. softening
|
Removing hardness
|
No
|
Yes
|
|
Removing chlorine
|
Yes
|
No
|
|
Protecting plumbing
|
Yes
|
Yes
|
|
Improving taste
|
Yes
|
No
|
Where filtration systems go and how they work
Filtration systems are typically installed either at the point of entry (where water enters the home) or at the point of use (at a specific tap).
Whole-house systems are installed on the main water line and treat all water entering the home. In Minnesota, these systems are often located in the basement due to climate conditions. By treating water at the point of entry, they supply filtered water to every tap.
Point-of-use systems treat water at a single location, usually for drinking and cooking. They are commonly installed under the sink and do not treat all water in the home.
Some point-of-use filters are designed to deliver water through the main faucet. These systems must maintain normal water pressure, so they typically use simpler filter media, such as granular activated carbon. Carbon filters are effective at reducing chlorine, taste, and odor, but they are not designed to remove many dissolved contaminants, such as arsenic, lead, or total dissolved solids.
Reverse osmosis (RO) systems are a more advanced type of point-of-use treatment. They use a membrane to reduce dissolved solids and certain contaminants. Because the process is slower, RO systems store treated water in a small tank and use a dedicated faucet.
Whole-house filtration systems may also use carbon to reduce chlorine, chloramine, and certain organic compounds. These systems often include additional components, such as sediment filters or other media, depending on the water conditions being addressed.
Advanced models may also include a metered controller that tells you when to replace the cartridge, so that you’re basing replacement on your usage and not just a general timeframe.
How these systems can work together in one home
Because different water technologies solve different problems, many Minnesota homes employ more than one solution. The appropriate setup for your home depends on your water test results and goals.
Whole-house water softener only
This approach is typically used in homes where hard water is the primary concern, without significant issues related to taste, odor, or contaminants.
A water softener reduces calcium and magnesium in the water. This can help limit scale buildup on fixtures and appliances and improve how soap performs during cleaning and washing.
Whole-house filtration only
This approach is typically used in homes without significant hardness, but with concerns related to taste, odor, or specific water quality issues.
Whole-house filtration systems can be designed to address chlorine taste, iron staining, sediment, and certain contaminants, depending on the type of media used.
Standalone whole-house filter and whole-house softener
This setup is common in Minnesota homes, where both hard water and additional water quality concerns are present.
In most cases, the filtration system is installed before the softener along the main water line. This allows the filter to reduce sediment, chlorine or iron before the water reaches the softener, helping the system operate more effectively.
The exact configuration can vary depending on your water quality, which is why testing and professional recommendations are important.
Combination softener + filtration system (all-in-one unit)
A combination system can provide both softening and filtration in a single unit, which may reduce space and simplify installation.
These systems are typically designed to address moderate levels of hardness and certain water quality concerns. In cases with higher levels of contamination or hardness, additional or separate treatment systems may be required.
How to figure out what your home needs
Begin by testing, not guessing
Visible signs, such as scale buildup, can indicate hard water, but they do not provide a complete picture of water quality. Water testing provides specific information about mineral content and potential contaminants. This is especially important for homes that rely on private wells.
As the MDH explains, your water should be tested by an accredited laboratory. Once you have the results, you can decide how best to proceed.
Common decision guide
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Is scale your main issue? → Consider a softener.
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Does your water have odor or staining? → Consider filtration.
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Do you want more comprehensive coverage? → Take the combination approach.
Why professional sizing & installation matter
Proper system sizing and installation can affect how water treatment equipment performs over time. Systems that are too small may not maintain adequate flow during periods of higher demand. In some cases, this can result in reduced water pressure at fixtures. Smaller tanks may also require more frequent media replacement.
Systems that are too large may not operate as intended. For example, insufficient flow can affect backwashing, which may reduce the effectiveness of the filtration media over time.
Get clarity with a free water sample
HSP makes it simple to get set up with the right system by offering a complimentary water quality analysis to better understand how your water can be effectively treated. An HSP Comfort Advisor will review your test results with you and recommend appropriate solutions.
Explore residential water treatment options in Minnesota
The right water treatment system starts with understanding your water. Home Service Plus offers water testing and expert recommendations based on Minnesota water conditions.
