Posted on by Charlie Avoles

As your local plumbing experts at St Paul Pipeworks, we’re often asked about hard water—what it is, how it affects your home, and what you can do about it. Living in the Minneapolis–St. Paul metro area, hard water is a fact of life for many, but not all, communities. Let’s break it down from a plumber’s perspective. 

What Is Hard Water?

Hard water is simply water that contains a higher concentration of dissolved minerals, primarily calcium and magnesium. These minerals are picked up as water moves through limestone, chalk, or gypsum deposits underground, which are common in many parts of Minnesota. 

How Is Water Hardness Measured?

Water hardness is typically measured in either parts per million (PPM) or grains per gallon (GPG) of calcium carbonate.  

Here’s how the U.S. Geological Survey classifies water hardness: 

Classification  PPM (mg/L)  GPG 
Soft  0–60  0–3.5 
Moderately Hard  61–120  3.5–7 
Hard  121–180  7–10.5 
Very Hard  181+  10.5+ 

A simple at-home “soap test” can give you a rough idea: if your tap water doesn’t produce suds easily and leaves a cloudy residue, it’s likely hard. 

Why Is Water Hard in Minneapolis and St. Paul?

The geology of the Twin Cities is the main culprit. Water in this region often percolates through limestone and dolomite aquifers, which are rich in calcium and magnesium. The Mississippi River, the primary water source for both Minneapolis and St. Paul, naturally contains moderate levels of these minerals. Groundwater from wells, common in the suburbs, can be even harder. 

Why Do Some Communities Have Harder Water Than Others? 

It all comes down to the water source: 

  • Minneapolis and St. Paul: Both cities draw from the Mississippi River and soften the water at their treatment plants. The softened water delivered to homes is typically classified as “slightly hard” or “moderately soft.” 
  • Suburbs: Many suburbs rely on groundwater wells, which often tap into mineral-rich aquifers. These communities can experience much harder water, sometimes in the “very hard” range. 

Which Twin Cities Communities Have the Hardest Water?

 

Some of the hardest city water in the metro area is found in suburbs that use well water. In contrast, northeastern suburbs and those directly served by Minneapolis or St. Paul water tend to have much softer water. 

The 20 communities with the hardest water in the Minneapolis/St. Paul area:

Dayton: 30-38 GPG  

Brooklyn Park: 24-34 GPG 

Spring Lake Park: 28 GPG 

Maple Grove: 22-36 GPG  

Chaska: 26 GPG 

Waconia: 26 GPG 

Chanhassen: 22-26 GPG 

Medina: 20–26 GPG 

Shorewood: 20-26 GPG 

Plymouth: 22-28 GPG 

New Brighton: 24 GPG 

Savage: 23 GPG 

Burnsville: 22-25 GPG 

Mound: 22 GPG 

Rogers: 22 GPG 

Albertville: 22 GPG 

Belle Plain: 22 GPG 

Hopkins: 21 GPG 

Shakopee: 21 GPG 

Wayzata: 20-24 GPG 

Is Well Water Hard?

Yes—well water in the Twin Cities area is almost always hard. Groundwater picks up minerals from the surrounding rock, leading to higher concentrations of calcium and magnesium. In some parts of the metro, hardness levels in private wells can reach up to 35 GPG. 

Why Is Hard Water Undesirable?

While hard water isn’t hazardous to drink, it poses several problems for your home: 

  • Scale Buildup: Calcium and magnesium form limescale, which clogs pipes, reduces water flow, and damages water heaters, dishwashers, and washing machines. 
  • Reduced Appliance Lifespan: Scale buildup forces appliances to work harder, increasing energy use and shortening their lifespan. 
  • Soap Inefficiency: Hard water makes it harder to form suds, so you use more soap and detergent, and your clothes and dishes may not come out as clean. 
  • Staining and Residue: Hard water leaves spots on glassware, stains on fixtures, and film on bathtubs and sinks. 

Is Hard or Soft Water Best for Drinking and Cooking?

The debate between hard water and soft water is common, especially in areas like the Twin Cities, where both types are present. Here’s a breakdown of the pros and cons of each, based on health, taste, and culinary impact. 

Hard vs Soft Water: What’s the Difference?

  • Hard water is rich in minerals, primarily calcium and magnesium. 
  • Soft water has had most of these minerals removed, often through a water softener, and may contain higher levels of sodium or potassium depending on the softening method. 

Drinking: Health and Taste Considerations

Hard Water

  • Health: Hard water is safe to drink for most people and can contribute to your daily calcium and magnesium intake, which are essential minerals for bone and heart health. However, excessive intake of magnesium can cause digestive issues in sensitive individuals. 
  • Taste: Many people describe hard water as having a “full-bodied” or “mineral” taste, which some enjoy and others find off-putting. Taste preference is highly subjective—studies show a nearly even split between those who prefer the taste of hard water and those who prefer soft water. 
  • Potential Downsides: There is some evidence that very hard water, consumed in large quantities over time, may contribute to kidney stone formation in susceptible individuals, but for most people, this is not a significant concern. 

Soft Water

  • Health: Soft water is also safe for most people. However, it contains less calcium and magnesium, and softened water may have higher sodium content, which could be a concern for those on sodium-restricted diets. 
  • Taste: Soft water is often described as “creamy” or “flat.” Some people find it more pleasant, while others notice a slight salty taste, especially if sodium is used in the softening process. 
  • Potential Downsides: For people with certain health conditions (like hypertension), the extra sodium in softened water may be undesirable. 

Cooking: Culinary Impacts

Hard Water

  • Cooking Effects: The minerals in hard water can affect food preparation. For example, hard water can alter the taste of tea and coffee, toughen vegetables, and interfere with the texture of baked goods by changing yeast activity and gluten development. It may also leave a film on cooked foods and cookware. 
  • Flavor: Hard water can have a mineral taste to foods and beverages, which some people find undesirable. 

Soft Water

  • Cooking Effects: Soft water is generally preferred for cooking and baking. It allows yeast to ferment more predictably, resulting in softer, fluffier baked goods. It also prevents mineral films from forming on food and cookware. 
  • Flavor: Soft water is less likely to alter the intended flavors of your recipes. 

How Can Water Softeners Help?

A water softener removes calcium and magnesium ions, typically replacing them with sodium or potassium ions. This process prevents scale buildup and the problems associated with hard water. 

Benefits of Soft Water:

  • Extends the life of plumbing and appliances 
  • Improves soap and detergent effectiveness 
  • Reduces spotting and staining on fixtures and dishes 
  • Leaves skin and hair feeling softer after bathing 

How Do Water Softeners Work?

Most residential softeners use an ion-exchange process: hard water passes through a tank filled with resin beads that attract and hold onto calcium and magnesium, swapping them for sodium or potassium. The system periodically regenerates by flushing the beads with a salt solution. 

Types of Water Softeners:

  • Salt-Based Ion Exchange: Most common and effective for high hardness. 
  • Salt-Free Conditioners: Use alternative methods (like template-assisted crystallization) to reduce scale, but don’t actually soften water. 
  • Dual-Tank Systems: Provide continuous soft water, even during regeneration. 

Should You Soften Hot Water Only, or Both Hot and Cold?

  • Hot Water Only: Some homeowners choose to soften just the hot water line, as most scale forms in water heaters and appliances. This reduces salt use and cost, but leaves cold water hard—so you’ll still see spots on glassware and may notice hard water effects in laundry and bathing. 
  • Hot and Cold Water: Softening the whole house provides the full benefits—protecting all plumbing, fixtures, and appliances, and improving water quality at every tap. However, it uses more salt and may not be necessary if cold water is only used for drinking and cooking (where some prefer hard water’s taste and mineral content). 

How St Paul Pipeworks Can Help

Even though Minneapolis and St. Paul provide softened water, many suburbs—especially those south of the Mississippi—still struggle with very hard water. If you’re noticing scale, spots, or appliance issues, we can help you assess your water hardness and recommend the best softening solution for your home. And if you’re in one of the northeastern suburbs with softer water, we’ll give you an honest assessment—sometimes, a softener just isn’t needed. 

Whether you’re dealing with hard water headaches or want to protect your investment in your home, St Paul Pipeworks is here to help you enjoy better water every day. CONTACT US TODAY with any hard water concerns.

 

Yours Truly,

Matthew Dettwiler

Social Media Manager

Understanding Hard Water in the Twin Cities: A Plumber’s Perspective