Water hardness and tap water in Viersen

Name: Water hardness and tap water in Viersen
Creator: Trinkwassermonitor
License: https://creativecommons.org/licenses/by/4.0/

Kreis Viersen, Nordrhein-Westfalen · Postcode 41747, 41748, 41749, 41751

This page is a translation of the German version; the German page is authoritative. German version · Report a translation error

Short answer: The tap water in Viersen has a total hardness of 12.7 °dH, hardness range “medium” (as of 13 January 2026). All tested parameters with a legal limit (16) meet the limits set by the German Drinking Water Ordinance (TrinkwV). Source: test report by NEW NiederrheinWasser. WaterScore: 99.3 out of 100 (data coverage: 7 of 7 core parameters).

Limits of the Drinking Water OrdinancemetAll tested parameters (16), at the waterworks
Water hardness12.7 °dH, mediumNo legal limit, only a range
Data coverageCore parameters: 7 of 7Score based on complete data

Verified drinking-water values

Parameter	Value	Limit (TrinkwV)	Sampling date	Source	Status
Nitrate	28.6 mg/L 57 % of the limit	50 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Nitrite	< 0.01 mg/L	0.5 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
PFAS (sum)	0.006 µg/L	0.1 µg/L in force since 12 January 2026 from 12 January 2028: additionally PFAS-4 0.02 µg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Lead	< 0.001 mg/L	0.01 mg/L from 12 January 2028: 0.005 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Arsenic	< 0.001 mg/L	0.01 mg/L new plants from 2028, all from 2036: 0.004 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Uranium	< 0.0001 mg/L	0.01 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Mercury	< 0.0001 mg/L	0.001 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Copper	< 0.01 mg/L	2 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Chloride	44.2 mg/L 18 % of the limit	250 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Sulphate	124.5 mg/L 50 % of the limit	250 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Sodium	19.5 mg/L	200 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Calcium	64.4 mg/L	–	13 January 2026	NEW NiederrheinWasser GmbH	verified
Magnesium	15.7 mg/L	–	13 January 2026	NEW NiederrheinWasser GmbH	verified
pH	7.68	6.5–9.5	13 January 2026	NEW NiederrheinWasser GmbH	verified
Total hardness	12.7 °dH (medium)	no legal limit	13 January 2026	NEW NiederrheinWasser GmbH	verified
Fluoride	< 0.1 mg/L	1.5 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Iron	< 0.01 mg/L	0.2 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Manganese	< 0.001 mg/L	0.05 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified
Ammonium	< 0.05 mg/L	0.5 mg/L	13 January 2026	NEW NiederrheinWasser GmbH	verified

Note from the test report (in the German original): Werte des Wasserwerks Viersen 102 vom 13.01.2026 (Reinwasser am Werk). Viersen wird aus zwei Wasserwerken versorgt: Das Werk Viersen beliefert die tiefer gelegenen Bereiche von Viersen und Süchteln, das Werk Dülken die Stadtteile Dülken und Boisheim sowie höher gelegene Bereiche von Viersen. Dülken lag am selben Tag bei 11,9 °dH, Nitrat 32,5 mg/l und PFAS-20 0,0030 µg/l – beide Werke im Härtebereich mittel. Welches Werk Ihre Adresse versorgt, zeigt die NEW-Trinkwasseranalyse nach Adresseingabe. Leitfähigkeit und mikrobiologische Werte sind dort nur mit Stand 2024 veröffentlicht und hier nicht aufgeführt.

Is a value wrong or out of date? Report an error – we check every report against the original source.

Water at your own tap: The values describe the water the supplier delivers – not automatically the water at your tap. The water supplier is responsible up to the service connection (Hausanschluss); the building owner is responsible for the pipes beyond it. Lead can dissolve from lead pipes, leaded solder joints or old brass fittings, especially when water has stood in the pipes for a long time (stagnant water); this mainly affects buildings constructed before about 1973. If water has stood in the pipes for several hours, let it run until it comes out cool. If you suspect lead pipes, a lead analysis of the stagnant water by an accredited laboratory will help.

Background on household plumbing, not a measurement: in Viersen, 58 % of buildings with living space were built before 1970, and a further 11 % between 1970 and 1979 (Zensus 2022, Statistisches Bundesamt, dl-de/by-2-0). (Zensus 2022) According to the German Environment Agency (Umweltbundesamt), lead pipes exist at most in houses built before 1973 – and by no means in all of them. Whether there are any in your house is known to the owner or a plumber. (UBA)

What the values mean for Viersen

Nitrate 28.6 mg/L – about 57 % of the limit of 50 mg/L and comparatively high for a city waterworks; the cause is usually nitrate from agriculture entering the raw water. Boiling does not reduce nitrate.
PFAS (sum of PFAS-20) 6 ng/L – about 6 % of the limit of 100 ng/L (since 12 January 2026).
Lead – not detectable at the waterworks. Lead gets into the water almost only through old lead pipes in household plumbing, not via the supplier.
Uranium – not detectable at the waterworks (limit 10 µg/L).
pH 7.68 – within the range of the Drinking Water Ordinance (6.5 to 9.5). The pH determines how corrosive the water is in household plumbing.

Water hardness in Viersen in everyday life

At 12.7 °dH, Viersen is in the hardness range “medium” (soft: below 8.4 °dH, medium: 8.4–14 °dH, hard: above 14 °dH).

Dose detergent for the hardness range “medium”.
As a rule of thumb, descale the kettle about every four to six weeks and the coffee machine as the manufacturer recommends.
A limescale protection device is not a must at medium hardness; regular descaling is often enough.

Baby food and low sodium: tap water in Viersen next to the bottled-water thresholds

Bottled water may only be labelled “suitable for preparing infant food” („geeignet für die Zubereitung von Säuglingsnahrung“) if it keeps to the maximum levels of the German Mineral and Table Water Ordinance (Mineral- und Tafelwasser-Verordnung, Annex 6). Here the published values for Viersen are shown next to them, each substance on its own. This is a comparison with labelling thresholds for bottled water, not a statement on whether your tap water is suitable for baby food. (Min/TafelWV, Anlage 6)

Values at the waterworks next to the maximum levels for bottled water “suitable for infant food”
Substance	Maximum level	Value in Viersen
Sodium	20 mg/l	19.5 mg/l – not above
Nitrate	10 mg/l	28.6 mg/l – above
Nitrite	0.02 mg/l	below the detection limit (0.01 mg/l) – not above
Sulphate	240 mg/l	124.5 mg/l – not above
Fluoride	0.7 mg/l	below the detection limit (0.1 mg/l) – not above
Manganese	0.05 mg/l	below the detection limit (0.001 mg/l) – not above
Arsenic	0.005 mg/l	below the detection limit (0.001 mg/l) – not above
Uranium	0.002 mg/l	below the detection limit (0.0001 mg/l) – not above

Against the other thresholds of Annex 6, the water would qualify as: low in sodium (“suitable for a low-sodium diet”) (Sodium 19.5 mg/l, threshold below 20 mg/l).

For context: the German Environment Agency (Umweltbundesamt) considers preparing baby food with bottled water carrying this label necessary only in rare cases, for example when tap water is temporarily allowed to contain more than 50 mg/l nitrate. (UBA 2016, p. 59) Water from lead pipes in the house is always unsuitable for infants. (UBA 2020, p. 16) The values apply at the waterworks. Questions about baby food are answered by your midwife, your paediatrician and the health office (Gesundheitsamt).

Frequently asked questions about tap water in Viersen

Can you drink the tap water in Viersen?

According to the verified values, yes: All tested parameters with a legal limit (16) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore: 99.3 out of 100 (data coverage: 7 of 7 core parameters). This applies to the water from the waterworks – restrictions can only arise from old household plumbing.

How hard is the water in Viersen?

The total hardness is 12.7 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.

Is there PFAS in the tap water in Viersen?

Yes, in measurable amounts: according to the published analysis by NEW NiederrheinWasser (as of 13 January 2026), the sum of PFAS-20 is 0.006 µg/l – that is 6 % of the limit of 0.1 µg/l, which has applied since 12 January 2026. Even this sum of all 20 substances is below the limit of 0.02 µg/l that applies from 12 January 2028 to the sum of four of them (PFAS-4).

Do I need to filter my tap water in Viersen?

Based on the verified supplier values, a filter is not necessary. It can make sense if you do not like the taste. If you suspect lead pipes in an old building, a filter does not help; a laboratory analysis at the tap does – that is a question of the household plumbing, not of the water leaving the works.

Is the nitrate level in Viersen a concern?

The value of 28.6 mg/L is below the limit of 50 mg/L, but higher than in many other evaluated cities. The limit of the Drinking Water Ordinance also applies to preparing baby food; mineral water labelled “suitable for preparing infant food” („geeignet für die Zubereitung von Säuglingsnahrung“) may contain at most 10 mg/L nitrate. Boiling does not help against nitrate.

WaterScore

Total99.3 / 100
Chemical safety95.7 / 100
Heavy metals100 / 100
PFAS100 / 100
Nutrients95.4 / 100
General parameters100 / 100
Data timeliness100 / 100
Data quality100 / 100

Data coverage: 7 of 7 core parameters. Missing parameters are neither estimated nor counted as harmless: the score is based only on the values available. It is not a health assessment and says nothing about the water beyond the service connection. Methodology v3: how we calculate the WaterScore.

Evidence: cite and check

NEW Trinkwasseranalyse – Wasserwerk Viersen 102 (Reinwasser), Wasserwerte vom 13.01.2026 (NEW NiederrheinWasser GmbH)

Suggested citation: Trinkwassermonitor (2026): Tap water in Viersen. Values according to the water supplier’s test report, sampling date 13 January 2026; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/viersen/

JSON: /api/v1/evidence?city=viersen

Data as of: 13 January 2026 · verified: 19 of 19 evaluated parameters.

This page shows only verified test data with sources, or states explicitly where data is missing (no estimated values). Cite as: “Trinkwassermonitor (2026). Tap water in Viersen. Retrieved from https://trinkwassermonitor.ink/en/tap-water/viersen/.”