Filtering tap water: how does a filter faucet work?

What is tap water filtering?

Filtering tap water involves adding an extra purification step to the water you dispense from your tap at home. Dutch tap water meets strict standards and is tested hundreds of times a year according to the industry organization Vewin, but the water still travels for kilometers through pipes between the treatment plant and your glass. Along the way, it may come into contact with traces of particles, chlorine, or substances from older plumbing.

Those who want to filter tap water usually do so at a single point: the kitchen tap. This can be done with a small attachment on the tap, with a filter pitcher, or with a system hidden in the kitchen cabinet and connected to a separate tap. The choice mainly determines how much the filter catches and how much convenience you get.

How exactly does a filter tap work?

A filter tap filters the water at the moment you turn it on. Driven by your household water pressure, the water flows through one or more filter stages, each with its own task, and emerges purified on the other side. No electricity is involved: the water pressure does the work.

In practice, there are two main types. A simple filter tap contains a single cartridge with activated carbon that catches chlorine, off-tastes, and some organic substances. In a more thorough system, the water goes through multiple stages, including a sediment filter, activated carbon, and finally a reverse osmosis membrane. That membrane has pores of approximately 0.0001 microns, small enough to stop even dissolved substances like PFAS and heavy metals.

At PureAqua, the core system works based on reverse osmosis. The filter device, The Source, is hidden in the kitchen cabinet and provides purified water through a separate pure-water tap. This allows you to draw filtered water from a stylish dispensing point, while the actual filtering happens out of sight and works completely without electricity.

The Source and the pure-water tap: two components

It is useful to know the difference. The Source is the device that filters the water, located inside the cabinet. The pure-water tap is the dispensing point on your countertop with an additional function for filtered water. Together they form a single system, but they are two separate parts connected to each other. A mineral filter then adds calcium and magnesium back, ensuring the water retains a natural, full flavor.

What filtration techniques are there?

Various techniques fall under the heading of "filtering tap water." They differ significantly in what they stop, the maintenance they require, and how thorough the result is. If you first want to know what is and isn't in Dutch tap water, read that overview first.

Activated carbon

Activated carbon acts like a sponge that attracts and holds substances. It is highly effective at improving odor and taste and catches chlorine, some pesticides, and medication residues. It is the most commonly used technique in filter pitchers and simple filter taps, but it does not remove limescale and only partially blocks dissolved salts or nitrates.

Sediment and ceramic filters

These filters have very small openings and catch solid particles: sand, rust, silt, and a large portion of microplastics. They are often used as pre-filters so that the finer filters downstream last longer. They barely change the taste and do not remove dissolved substances.

Reverse osmosis (RO)

Reverse osmosis is the most thorough household technique. Water is forced through a membrane with extremely small pores that blocks up to 99% of unwanted substances, including PFAS, microplastics, medication residues, pesticides, and heavy metals. Because the membrane also removes minerals, a mineral filter adds calcium and magnesium back afterward. This is the technology behind the PureAqua system, The Source. We have separately listed the considerations associated with this filtration technique.

UV and water softeners

UV light renders bacteria and viruses harmless, but it does not change the water's composition, and therefore has no effect on the impact of filtering on pH levels. A water softener focuses specifically on limescale and makes water softer for the entire house, but it does not filter contaminants. Whether you choose a softener with or without regeneration salt makes a big difference in the result. Both are supplementary and not a replacement for a drinking water filter.

Why should you filter tap water?

The main reason is having control over taste and purity. Even though tap water is safe, many people want to manage that final step themselves. According to the RIVM, PFAS, medication residues, and microplastics are substances present in the environment in low concentrations, and exposure should be kept as low as possible. A thorough filter helps reduce that exposure via drinking water. If you travel often, that question also arises on the road: we researched whether you can drink tap water while on vacation and what to look out for.

In addition, there is the aspect of taste and convenience. Filtered water has no chlorine odor, tea and coffee become clearer, and you no longer need to carry bottles or refill pitchers. This also saves hassle with storing water in a pitcher or bottle, as you always dispense it fresh. At PureAqua, we find that customers mainly choose a solution that combines pure water with convenience: hidden from view and straight from the tap.

Benefits of a filter tap

A filter tap has several clear advantages over a pitcher or bottle:

• Instantly filtered water: you dispense pure water right away, with no waiting or refilling.
• Better taste: chlorine and off-tastes disappear, which you will notice especially in tea and coffee.
• More purity: a reverse osmosis system removes up to 99% of unwanted substances like PFAS and microplastics.
• Space-saving: no more pitchers or crates of bottles; the filter is hidden in the cabinet.
• Works without electricity: the PureAqua system uses only water pressure, so no power outlet is required.

Points of attention and drawbacks

Balanced against these benefits are a few things to consider beforehand:

• Not every filter does the same: a simple attachment filter mainly improves taste, whereas only reverse osmosis thoroughly tackles substances like PFAS.
• Maintenance: filters must be replaced periodically; at PureAqua, this is generally once a year with a filter set starting at 75 euros for a 2-pack.
• Tap-mounted filters: these can look obstructive and reduce flow rate; a built-in system does not have this issue.
• Filter pitchers: water quality can actually deteriorate due to stagnant water in the pitcher if you don't replace the cartridge in time.
• No limescale solution: a drinking water filter does not soften water; you need a water softener for that.

Comparison table: filter methods side by side

Buying advice: which filter suits you?

The choice depends on what you want to achieve. If it's mainly about a better-tasting glass without a chlorine flavor, then a filter pitcher or an activated carbon filter may suffice. If you want to specifically remove substances like PFAS, microplastics, and medication residues from your drinking water, then reverse osmosis is the most complete choice. A comparison of all household filter types will help you refine that choice.

If you are looking for convenience and a clean result, a built-in system with a separate pure-water tap is the most pleasant: the filter is out of sight and you dispense pure water from a beautiful tap. Compare the options in the pure-water taps collection or view all pure-water taps. Are you unsure about your water quality?

Frequently asked questions

Conclusion

Filtering tap water gives you control over taste and purity, and a filter tap makes that most convenient: the water is filtered the moment you dispense it, without a pitcher or bottle. For purely better taste, activated carbon is sufficient, but if you want to thoroughly tackle substances like PFAS, microplastics, and medication residues, then reverse osmosis is the most complete choice.

With the PureAqua The Source system, you combine that purity with convenience: the filter sits invisibly in the cabinet, you dispense from a stylish pure-water tap, it works without electricity, and a mineral filter keeps the taste on point. This way, you consciously choose the filtering method that fits your water and household.