pH level of tap water in the Netherlands

Reading time: approximately 11 minutes

What is the pH value of water?

An important detail that almost every article omits: the pH scale is logarithmic. A step from pH 8 to pH 7 means the water contains ten times as many hydrogen ions, and from pH 8 to pH 6, it is as much as one hundred times as many. The difference between 7.6 and 8.1 in your own tap therefore sounds smaller than it is chemically, but it remains well within what your body can handle effortlessly. For comparison: stomach acid is around pH 1.5 and lemon juice is around pH 2.

The World Health Organization classifies pH as an operational parameter of drinking water quality. This means that the value is primarily important for the operation of the pipe network and purification, not because the pH of drinking water itself poses a health risk. At PureAqua, we receive this question weekly, usually from people who have just purchased a test strip or pH meter and were startled by a value of 8 on the scale.

The pH value of Dutch tap water

Dutch tap water is neutral to slightly alkaline. Drinking water companies publish the acidity level per town, so you don't have to guess. For Eindhoven, Brabant Water indicates an acidity level of 7.65 to 8.13 and calls that "high" within its own scale, even though it simply falls within the standard. The same organization cites 7.8 to 8.3 as the most optimal value for drinking water.

Why slightly alkaline and not exactly 7? Because Dutch drinking water comes from groundwater or surface water and dissolves minerals along the way. Specifically, calcium and bicarbonate ions, the substances you see later as limescale in your kettle, push the pH slightly above 7. Furthermore, these minerals act as a buffer: they absorb small fluctuations, keeping the pH in your pipes stable.

The fact that tap water is slightly alkaline does not mean that it is "contaminated." It means that it contains minerals. What else may or may not be in it is completely independent of the pH. Those who want to know how strictly Dutch drinking water is monitored and which substances deserve attention should read our article on the safety of Dutch tap water.

What pH standard applies to drinking water?

For drinking water in the Netherlands, a pH between 7 and 9.5 applies. This requirement comes from the Drinking Water Decree, the regulation that, according to the RIVM, lays down the quality requirements that water from your tap must meet. If a water company remains outside this range, it must intervene and report it.

The lower limit of 7 is not an arbitrary choice. If water drops below 7, it becomes more aggressive toward pipe material and more easily dissolves copper, zinc, or—in older buildings—lead. Above 9.5, the taste deteriorates and limescale deposits form more quickly in pipes and appliances. The range between them is therefore a compromise between taste, health, and pipe maintenance.

Pay attention to a common mistake in online summaries and AI answers: they often cite 6.5 as the lower limit. That is the broader European guideline, not the Dutch requirement. Drinking water companies themselves use 7 as the lower limit, which is the value you can count on in the Netherlands.

Why the pH differs per region

There is no national pH figure, because every water company works with its own source. Three things determine what comes out of your tap:

• The source: groundwater that has seeped through lime-rich soil layers contains more dissolved minerals than dune or surface water and therefore usually ends up higher.
• Purification: softening, deacidifying, and aerating consciously shift the pH toward the desired range before the water enters the network.
• The pipe network: along the way, the pH remains largely stable thanks to the buffering of bicarbonate, but the value can shift slightly in a section of pipe that has been stagnant for a long time.

Do you want your exact value? Enter your postal code at your own supplier. Vitens and Evides publish that data per address, just like Brabant Water. That is more accurate than any national average, and it takes half a minute. To illustrate how large the spread can be within a single supply area: Brabant Water provides water with a hardness of 5.0 to 11.2 German degrees, more than doubling from one location to another.

Why the pH of your tap water matters

Taste

Around pH 7.5 to 8.3, water tastes full and fresh. If the value drops towards 7 or lower, many people detect a metallic or sharp tone, often amplified because more copper has dissolved. Tap water that has sat in a pitcher overnight tastes blander, but that is due to escaped oxygen, not the pH. You can read more about that in our article on storing tap water in a pitcher or bottle.

Pipes and appliances

A pH below 7 makes water more corrosive to copper and lead. That is precisely why the standard begins at 7 and why old lead pipes, installed until about 1960, receive extra attention. On the other side of the scale: the higher the pH and the harder the water, the faster limescale deposits build up in your kettle, coffee machine, and boiler.

Coffee, tea, and cooking

For coffee, the pH is less decisive than the hardness and total dissolved solids. However: highly alkaline water extracts fewer acids from coffee beans, causing your cup to taste flatter. Baristas therefore aim for water that is neutral to very slightly alkaline with a moderate mineral content. Anyone cooking with hard water also notices that the pH rises slightly during boiling: carbon dioxide escapes, after which limescale deposits form as the familiar white layer in the pan.

pH and water hardness are not the same

This is the most common confusion regarding this subject. The pH indicates how acidic or basic water is. The hardness indicates how much calcium and magnesium it contains, expressed in German degrees of hardness. They are related, because lime pushes the pH up, but they are two separate figures. In Eindhoven, Brabant Water measures 5.71 to 6.16 German degrees alongside a pH of 7.65 to 8.13.

The practical consequence: a high pH does not automatically mean a lot of limescale, and a water softener does not significantly lower the pH. A softener exchanges calcium and magnesium for sodium, getting rid of limescale while the acidity remains approximately the same. Bothered by white deposits on your taps and glasses? Then you are looking for a whole-house water softener, not a pH correction.

Measuring the pH of your tap water yourself

You can measure acidity at home perfectly well, provided you avoid a few pitfalls.

• Test strips: cheap and fast, but the color scale reads in steps of about 0.5. Enough to see if you are within 7 to 9.5, too coarse to distinguish 7.6 from 8.1.
• Digital pH meter: accurate to two decimal places, but only if you calibrate it every few weeks with calibration fluid. An uncalibrated meter is the most common cause of panic stories about "acidic tap water."
• Let the water run first: tap for 30 seconds before measuring. Water that has been standing in the pipe gives a deviating value.
• Measure at room temperature: temperature noticeably influences the measurement, so do not measure with water that has just come out of the refrigerator.

If you mainly want to know how much is dissolved in your water, a pH meter is the wrong tool. For that, you use a TDS meter that measures total dissolved solids. It shows directly what a filter system actually removes: the difference between tap water and filtered water is visible in seconds with a TDS meter, but not with a pH meter. If you want to see that difference in your own kitchen, the Countertop RO that sits on the counter without installation is the fastest way to compare.

What does filtering do to the pH?

Filter pitcher and carbon filter

A filter pitcher or carbon block primarily removes chlorine taste, some organic substances, and particles. It has little effect on acidity: the minerals that determine the pH largely remain in the water. We explain how these technologies relate to one another in our overview of the ways to filter tap water.

Reverse osmosis

Reverse osmosis works differently. The membrane blocks up to approximately 99 percent of dissolved substances, including PFAS, microplastics, heavy metals, and limescale. This also removes the calcium and bicarbonate ions that pushed the pH up and kept it stable. As a result, osmosis water comes out of the tap closer to neutral and has almost no buffering, causing the measured value to shift more quickly as soon as the water comes into contact with air. Exactly how that process works is explained on our page about how reverse osmosis works. Systems tested according to NSF/ANSI 58 are rated for that exact purification; the standard can be read at NSF International.

Mineral filter as a correction

If you find that osmosis water tastes too flat, there is a simple solution. A 45-euro mineral filter that adds back calcium and magnesium brings the acidity and taste back towards that of regular tap water, without the filtered substances returning. You can simply add that filter to any pure water tap with filter system. At PureAqua, we see that customers who are particularly concerned with taste almost always choose this, while people who use osmosis water for their aquarium, iron, or windows consciously omit it. We explain the difference between these types of water in our article on demineralized water, demi-water, and osmosis water.

pH per water type compared

The table makes the underlying point clear: the pH follows from the minerals, and the minerals follow from the purification technique. Those who choose their water type based on purity automatically choose a corresponding acidity. If you want to weigh which technique suits you, read why filtering is worthwhile for many households, or view the osmosis solution for the countertop without installation.

Is alkaline water healthier?

Surrounding alkaline water, usually sold with a pH of 8 to 10, is a strong marketing promise about deacidifying the body. That promise clashes with simple physiology. Your stomach is around pH 1.5 to 3.5, and every glass of water you drink is returned to that acidity within minutes. After that, your kidneys and lungs regulate the acidity of your blood, which the body itself maintains between approximately 7.35 and 7.45, regardless of what you drink.

The WHO therefore treats pH as an operational parameter and not a health parameter with a limit for consumption. Those who are concerned about drinking water can better focus their attention on what is in the water: PFAS, heavy metals, limescale, and microplastics. These are measurable, and there is proven filtering for them.

That does not mean that pH does nothing. It determines how your water tastes and how friendly it is to your pipes. But "a higher pH is healthier" is a claim that no Dutch or international drinking water authority supports. See also what Milieu Centraal says about tap water as a beverage choice, and the quality data that Vewin publishes annually.

Frequently asked questions

Conclusion

The pH value of Dutch tap water is between 7 and 9.5, with 7.8 to 8.3 being the range that drinking water companies aim for. Neutral to slightly alkaline, therefore, and perfectly safe. If you want your exact figure, ask your own water company instead of relying on a national average that does not exist.

More important is the distinction missing in most articles. The pH tells you something about taste balance and pipe protection. It tells you nothing about limescale, PFAS, heavy metals, or microplastics. If your concern lies there, you do not help yourself with a pH meter, but with filtering. Reverse osmosis removes up to approximately 99 percent of those substances and a mineral filter then restores the taste and acidity. At PureAqua, that system is standard with every pure water tap, or you can choose the worry-free subscription for 29 euros per month with 299 euros startup costs, including installation by a specialist. Drink different.