Water filter with minerals: how it works

Reading time: ~12 minutes

1. What is a water filter with minerals?

A water filter with minerals is a filter system that does two things in sequence. First purification: contaminants such as PFAS, microplastics, heavy metals, chlorine and medicine residues are removed from the water. Then mineralisation: the purified water flows through a layer of mineral-rich rock, which releases calcium, magnesium and potassium into the water. So you're left with clean water that still contains the minerals that give tap water its taste and softness.

The difference sounds subtle, but it's the heart of the question. At PureFilter, we see that customers mainly hesitate on exactly this point: they want to get rid of PFAS and microplastics, but don't want to feel they'll end up drinking "empty" water. If you want to first understand how the different techniques relate to each other, our overview of the different types of water filters will quickly get you up to speed.

Watch the terminology in webshops. "Mineral-retaining" and "mineralising" don't mean the same thing. A carbon filter retains minerals simply because it doesn't remove them. A system with mineral rock adds them. And a reverse osmosis system first removes almost everything and then needs a separate mineralisation stage to bring levels back up.

2. Why minerals in tap water matter

Calcium and magnesium occur naturally in groundwater. According to Vitens, the exact amount of calcium and magnesium determines how hard your water is, and calcium is good for your bones, among other things. Those same minerals give the full, rounded taste you recognise from good tap water.

Dutch water is already being softened

This is the point many people miss. Drinking water companies centrally soften the water at many locations and deliberately reduce the amount of calcium and magnesium in the process, so you get less limescale build-up in your appliances. Milieu Centraal reports that by now almost two-thirds of Dutch municipalities have soft water. The law does set a floor: drinking water companies aren't allowed to remove all the calcium and magnesium and, according to Vitens, must maintain a minimum hardness of 5.6 °dH.

In other words: your tap water is already partly softened before it reaches your home. If you then filter with a technique that also removes the remaining minerals, you're shifting twice in the same direction. You can read exactly how hard or soft the water is in your region in our overview of hard water in the Netherlands.

What minerals do and don't do

Staying honest matters here. The World Health Organization concludes in its report on calcium and magnesium in drinking water that food is the main source of both minerals; drinking water provides an additional contribution. For comparison: EFSA sets the adequate intake of magnesium at 350 mg per day for men and 300 mg per day for women. A glass of water isn't going to cover that on its own.

A water filter with minerals is therefore not a supplement. It's a way to stop your filter making the water poorer than it already was, with taste and softness as the noticeable result. More background is in our explanation of minerals in drinking water.

3. Which filters remove minerals, and which don't

Not every filter technique handles minerals the same way. Here's the overview you need before buying anything.

Activated carbon: leaves minerals alone

Activated carbon works through adsorption: substances stick to the carbon surface. Chlorine, taste and odour compounds, medicine residues and organic compounds are removed; dissolved mineral salts such as calcium and magnesium largely pass through. According to NSF International, adsorption filtration falls under standards NSF/ANSI 42 (taste and odour) and 53 (health-related substances). So a carbon filter retains minerals but doesn't add any.

Reverse osmosis: removes almost everything

An RO membrane holds back virtually all dissolved substances, including calcium, magnesium and potassium. The result is very pure, but also mineral-poor and flat in taste. That's why manufacturers sell separate mineralisation filters and pH-boosting cartridges as an add-on. If you want that trade-off in detail, read our analysis of whether osmosis water is healthy or unhealthy.

Ion exchangers and water softeners: swap minerals around

An ion exchanger replaces calcium and magnesium ions with sodium or hydrogen. You get less limescale, but also less of the minerals you actually wanted to keep. Milieu Centraal also points out that softening water yourself usually isn't necessary and carries risks: in very soft water, harmful substances can dissolve, and bacteria can grow on a poorly maintained filter. We explain the difference between softening and filtering in water softener or water filter.

Gravity filters with mineral stones

Jugs and tanks with Elvan or Sunmac stones are popular in the Netherlands. They do genuinely mineralise, but you have to keep refilling and the flow is slow. You can read how that category compares to a system under your sink in our explanation of gravity filters.

Filter jugs

The classic filter jug combines activated carbon with ion-exchange resins. Those resins lower the hardness, and therefore also the calcium and magnesium content. Nice for your kettle, less logical if you specifically want mineral-rich water. We compared the best-known variant in our Brita water filter review.

4. How mineralising works in practice

The PureFilter Mineral+ sits under your sink on the cold water pipe and works in five steps. The first four steps purify: coarse dirt out, then PFAS, microplastics, heavy metals such as lead and copper, fluoride, nitrates, medicine residues, chlorine and flavour compounds. Up to around 99% of more than 100 contaminants is removed. The system is certified to NSF 42, 53, 61 and 372.

The fifth step is the mineralisation stage: Swedish Mineral Rock™. The purified water passes through a layer of natural rock that releases calcium, magnesium and potassium. So the water that comes out of your tap is clean and mineral-rich at the same time, without you having to stack up separate cartridges.

You install it yourself in 5 to 10 minutes, without a plumber and without tools. Everything is in the box and the water comes from your existing tap, so your kitchen doesn't change. Do you have a Quooker? It doesn't filter anything itself, but the two combine well if you place the filter for the Quooker system on the cold water supply. We explain that step by step on our page about the water filter for the Quooker.

5. Advantages of a water filter with minerals

• Pure yet full of flavour: you remove more than 100 substances and keep calcium, magnesium and potassium in your glass.
• Softer-feeling water: without a chlorine smell and with a rounded taste, noticeable in tea and coffee too.
• No refilling: the filter sits inline under your sink, so no jug in the fridge and no waiting for it to flow through.
• Demonstrably tested: NSF 42, 53, 61 and 372 instead of just a marketing claim about "healthy water".
• Cheaper than bottles: less than one cent per litre for the replacement filter, versus €0.40 to €1.00 per litre for spring water.
• Try it risk-free: 40 days free returns and a 5-year warranty on the system.

If you're mainly looking for protection against PFAS, the focused explanation on our page about the water filter against PFAS is the handiest starting point.

6. Points to note and persistent misconceptions

"Mineral water is healthier than tap water"

That's an oversimplification. Dutch tap water meets strict legal requirements; the RIVM describes how those requirements are laid down in the Drinking Water Decree and the Drinking Water Regulation, with, for example, a maximum of 5 micrograms of lead per litre. Bottled water isn't automatically richer in minerals or safer, and costs a factor of hundreds more per litre.

"A filter with mineral stones makes water alkaline, so it's better"

Mineral rock raises the pH a little. The claim that mineral stones thereby prevent diseases or "de-acidify" the body isn't backed by evidence. We don't make that claim, and you don't need to pay for it. The noticeable effect is in taste and softness, not in medical promises.

"A water filter is unnecessary in the Netherlands"

Milieu Centraal indeed advises that a water filter isn't necessary because of the high water quality, and warns of bacterial growth on poorly maintained filters. That argument is serious and it's good that it's raised. It's also exactly why a sealed inline system with a fixed replacement point is a different product from an open jug sitting on the counter for days: there's no standing water and no open filter tray.

Maintenance isn't a minor detail

A filter left in too long works less well. Budget for a replacement filter every 12 months with normal household use, with a capacity of 15,000 to 20,000 litres. You don't clean an inline filter, you replace it. You'll find new cartridges in our replacement filters.

7. Comparison: which systems actually mineralise?

Dutch search results for "water filter with minerals" mostly consist of mineral stones for gravity jugs and separate mineralisation cartridges for RO systems. Below we set the categories side by side, with the prices as they appeared in Dutch results in August 2026.

The conclusion from that table isn't that mineral stones are bad, but that with most alternatives you're making two purchases: a system that purifies and something that mineralises afterwards. A more detailed comparison of under-sink choices is in our overview of the best under-sink water filter, and the broader market comparison is on our page about the best water filter.

8. What does a water filter with minerals cost?

The PureFilter Mineral+ costs €149.00 with the first filter included. If you want to buy ahead, there are variants with filters for 24 months (€199.00) and 36 months (€239.00). A separate replacement filter is €65.00 and lasts up to 12 months; the duo set with two cartridges costs €115.00.

Converted, that's roughly less than one cent per litre in filter costs. Tap water itself costs a few tenths of a cent per litre on top of that. Compare that with bottled water, where a household easily spends €1 to €2 a day, and the difference over a year runs into the hundreds of euros. If you want to work it out for yourself with your own water bill, use the figures from our article on what a cubic metre of water costs.

9. Buying advice: choose in four steps

1. Determine your main goal. If you want to get rid of PFAS, microplastics and heavy metals, you need demonstrable filtration, not mineral rock alone.
2. Check whether the system mineralises or only retains. "Mineral-retaining" means nothing is added; check whether there's an explicit mineralisation stage.
3. Ask about certification. NSF 42, 53, 61 and 372 are verifiable. A claim like "healthy water" isn't.
4. Calculate replacement costs, not the purchase price. A cheap system with four cartridges a year is more expensive than an inline filter you replace once a year.

Still unsure between types? The complete water filter for home range helps you compare purchase price, capacity and maintenance at a glance.

10. Frequently asked questions

11. Conclusion

A water filter with minerals solves a problem you only notice once you look for it: your tap water is already centrally softened in almost two-thirds of Dutch municipalities, and a filter that also removes the remaining minerals makes your water flatter than necessary. Purifying and mineralising therefore belong together.

When comparing, look at three things: what the system demonstrably removes, whether it actually mineralises rather than just retains, and what it costs you per year including replacement filters. The PureFilter Mineral+ combines all three in one system under your sink: more than 100 contaminants out, calcium, magnesium and potassium in, installation in 5 to 10 minutes, and 40 days to try it out at ease.