Water softener or water filter: what's the difference?

Published on June 25, 2026 | Reading time: ~10 minutes

Many people hesitate between a water softener and a water filter. Both improve water quality, but in a completely different way and for different purposes. Yet, they are often confused, which can lead to an expensive and unnecessary purchase.

According to Vewin, tap water in the Netherlands contains an average of 150 to 400 mg of calcium and magnesium per liter, depending on the region. At the same time, the RIVM states that more than 100 different micro-contaminants have been found in drinking water sources, including PFAS, medicine residues, and pesticides. These are two completely different problems, each requiring its own solution.

1. What does a water softener do?

A water softener is connected to the main water supply and treats all the water flowing through the house: shower water, washing water, and drinking water. That sounds comprehensive, but it exclusively solves the limescale problem.

The installation requires a professional and costs an average of 800 to 2,000 euros including installation. After that, the system requires regular maintenance: refilling regeneration salt and periodic cleaning of the resin cylinder. Annual maintenance costs are around 50 to 150 euros.

What does a water softener solve?

• White limescale deposits on faucets, showers, and tiles
• Limescale buildup in kettles, dishwashers, and washing machines
• Higher energy consumption due to limescale buildup in the central heating boiler
• Stiff and gray laundry due to hardness minerals

2. What does a water filter do?

There are several filter types: activated carbon filters, sediment filters, ceramic filters, and reverse osmosis systems. An inline water filter, such as the PureFilter Mineral+, is placed directly on the cold water tap under the sink and filters only the drinking water you actually consume.

What does a quality water filter filter?

• Chlorine and chlorine compounds
• PFAS (poly- and perfluoroalkyl substances)
• Heavy metals such as lead, nickel, and copper
• Medicine residues and hormone-disrupting substances
• Microplastics and sediment
• Odor and taste substances that make tap water less fresh

The PureFilter Mineral+ goes a step further: using Swedish Mineral Rock, it adds calcium, magnesium, and potassium to the filtered water. This way, you drink water that is both purified and mineralized, something no water softener offers.

3. Comparison table: water softener vs. water filter

4. Why does a water softener affect drinking water?

This is the point most comparison articles skip. A water softener removes calcium and magnesium, but replaces them with sodium ions. This has two consequences for those who also drink the water.

Firstly, the sodium content of the drinking water increases. The Health Council advises limiting sodium intake. For people with kidney problems, high blood pressure, or a low-sodium diet, softened tap water can be undesirable. Water softener suppliers therefore recommend installing a separate tap for drinking water, which incurs additional costs.

Secondly, calcium and magnesium disappear completely. These minerals are essential: calcium is needed for bones and teeth, magnesium for muscle function. Tap water in the Netherlands provides an average of 10 to 15% of the daily magnesium requirement. A softener removes that contribution. An inline water filter with Swedish Mineral Rock actually adds minerals, so you get a healthy dose of calcium, magnesium, and potassium with each glass of water.

5. When to choose a water softener?

A water softener is useful if you live in a region with extremely hard water (more than 20 dH or more than 350 mg/liter of calcium and magnesium) and limescale causes significant damage to expensive appliances. This applies particularly to parts of North Brabant, Limburg, and Zeeland.

Choose a water softener if:

• Your central heating boiler, washing machine, or dishwasher frequently breaks down due to limescale
• You demonstrably have extremely hard water and experience damage from it
• You want to keep a separate cold water tap for unfiltered drinking water

Good to know: in large parts of the Netherlands, the water is moderately hard (10 to 18 dH). In those areas, a water softener is often not necessary at all, and a drinking water filter is a more effective investment.

6. Is a water filter the better choice for drinking water?

If the question is "how do I make my drinking water healthier and tastier?", then a water filter is always the right choice, regardless of the water hardness in your region. Chlorine, PFAS, and heavy metals are present in almost all tap water areas in the Netherlands. A water softener does not remove these substances.

At PureFilter, we see that customers primarily choose the PureFilter Mineral+ due to the combination of purification and mineralization. People who previously bought expensive bottled water or had a water softener installed are surprised by how great the taste difference is and how easy the installation is: 5 to 10 minutes, no plumber needed.

An inline water filter is also the more sustainable choice. Bottled water costs an average of 0.40 to 1.50 euros per liter and produces plastic waste. A PureFilter cartridge filters 15,000 to 20,000 liters for less than 0.005 euros per liter, while also contributing to less plastic pollution.

7. Can you combine a water softener and a water filter?

Yes, you can, and many households in regions with extremely hard water do. The combination then looks like this: the water softener treats household and shower water to prevent limescale, and an inline water filter for the kitchen filters the drinking water and adds back minerals that the softener has removed.

This way, you benefit from the best of both worlds: no limescale on appliances and still healthy, tasty drinking water directly from the tap. The PureFilter Mineral+ under the sink easily connects to the existing cold water pipe, even if there is already a water softener in the meter cupboard.

If you don't suffer from extreme limescale but want better drinking water, then the PureFilter Mineral+ is sufficient as the sole solution, and a water softener is an unnecessary investment.

Frequently asked questions about water softener or water filter

Conclusion: water softener or water filter?

A water softener and a water filter are not competitors; they solve different problems. A water softener tackles limescale throughout the house. A water filter makes your drinking water healthier by removing contaminants. Anyone who wants better drinking water will always benefit from a water filter, regardless of water hardness.

Moreover, the disadvantage of a water softener is that it replaces calcium and magnesium with sodium, meaning you still need a separate solution for drinking water. An inline water filter like the PureFilter Mineral+ does the opposite: it removes harmful substances and adds healthy minerals via Swedish Mineral Rock.

If you live in an area with extremely hard water and suffer from damaged appliances, a whole-house water softener can be beneficial, preferably combined with the PureFilter Mineral+ for clean drinking water. If you live in an area with normally hard water, then the PureFilter Mineral+ alone is the most effective and affordable choice.