TrinkwassermonitorTap water in Germany

Water hardness and tap water in Hilden

Kreis Mettmann, Nordrhein-Westfalen · Postcode 40721, 40723, 40724

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 Hilden has a total hardness of 11 °dH, hardness range “medium” (as of 2025). All tested parameters with a legal limit (20) meet the limits set by the German Drinking Water Ordinance (TrinkwV). Source: test report by Stadtwerke Hilden. WaterScore: 100 out of 100 (data coverage: 7 of 7 core parameters).

Verified drinking-water values

ParameterValueLimit (TrinkwV)Sampling dateSourceStatus
Nitrate15.5 mg/L
50 mg/L2025Stadtwerke Hilden GmbHverified
Nitrite< 0.001 mg/L0.5 mg/L2025Stadtwerke Hilden GmbHverified
PFAS (sum)0.042 µg/L
0.1 µg/L

2025Stadtwerke Hilden GmbHverified
Lead< 0.001 mg/L0.01 mg/L
2025Stadtwerke Hilden GmbHverified
Arsenic< 0.001 mg/L0.01 mg/L
2025Stadtwerke Hilden GmbHverified
Uranium< 0.001 mg/L0.01 mg/L2025Stadtwerke Hilden GmbHverified
Mercury< 0.0001 mg/L0.001 mg/L2025Stadtwerke Hilden GmbHverified
Copper< 0.001 mg/L2 mg/L2025Stadtwerke Hilden GmbHverified
Cadmium< 0.0002 mg/L0.003 mg/L2025Stadtwerke Hilden GmbHverified
Chromium< 0.0005 mg/L0.025 mg/L
2025Stadtwerke Hilden GmbHverified
Nickel0.002 mg/L
0.02 mg/L2025Stadtwerke Hilden GmbHverified
Chloride28.4 mg/L
250 mg/L2025Stadtwerke Hilden GmbHverified
Sulphate50.7 mg/L
250 mg/L2025Stadtwerke Hilden GmbHverified
Sodium27.1 mg/L
200 mg/L2025Stadtwerke Hilden GmbHverified
Calcium61.2 mg/L–2025Stadtwerke Hilden GmbHverified
Magnesium10.3 mg/L–2025Stadtwerke Hilden GmbHverified
pH7.576.5–9.52025Stadtwerke Hilden GmbHverified
Total hardness11 °dH (medium)no legal limit2025Stadtwerke Hilden GmbHverified
Electrical conductivity503 µS/cm–2025Stadtwerke Hilden GmbHverified
Fluoride0.06 mg/L1.5 mg/L2025Stadtwerke Hilden GmbHverified
Iron< 0.01 mg/L0.2 mg/L2025Stadtwerke Hilden GmbHverified
Manganese< 0.001 mg/L0.05 mg/L2025Stadtwerke Hilden GmbHverified
Ammonium< 0.02 mg/L0.5 mg/L2025Stadtwerke Hilden GmbHverified
Coliform bacteria0 KBE/100ml0 per 100 ml2025Stadtwerke Hilden GmbHverified
Trihalomethanes (THM)< 0.05 µg/L50 µg/L2025Stadtwerke Hilden GmbHverified

Note from the test report (in the German original): Stadtwerke Hilden · Jahresmittelwerte 2025 des Trinkwassers aus dem Wasserwerk Baumberg, gemessen am Wasserwerksausgang nach Hilden. Laut Stadtwerken schwankt die Härte zwischen 10 und 13 °dH; für die Einstellung von Geräten und die Waschmitteldosierung empfehlen sie 13 °dH. Die zusätzlich gedruckte Angabe von 0,70 mmol/l passt nicht zu 11,0 °dH und ist deshalb nicht übernommen.

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 Hilden, 51 % of buildings with living space were built before 1970, and a further 18 % 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 Hilden

Water hardness in Hilden in everyday life

At 11 °dH, Hilden is in the hardness range “medium” (soft: below 8.4 °dH, medium: 8.4–14 °dH, hard: above 14 °dH).

Baby food and low sodium: tap water in Hilden 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 Hilden 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”
SubstanceMaximum levelValue in Hilden
Sodium20 mg/l27.1 mg/l – above
Nitrate10 mg/l15.5 mg/l – above
Nitrite0.02 mg/lbelow the detection limit (0.001 mg/l) – not above
Sulphate240 mg/l50.7 mg/l – not above
Fluoride0.7 mg/l0.06 mg/l – not above
Manganese0.05 mg/lbelow the detection limit (0.001 mg/l) – not above
Arsenic0.005 mg/lbelow the detection limit (0.001 mg/l) – not above
Uranium0.002 mg/lbelow the detection limit (0.001 mg/l) – not above

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 Hilden

Can you drink the tap water in Hilden?

According to the verified values, yes: All tested parameters with a legal limit (20) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore: 100 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 Hilden?

The total hardness is 11 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.

Is there PFAS in the tap water in Hilden?

Yes, in measurable amounts: according to the published analysis by Stadtwerke Hilden (as of 2025), the sum of PFAS-20 is 0.042 (middle of the range given by the supplier) µg/l – that is 42 % of the limit of 0.1 µg/l, which has applied since 12 January 2026.

Do I need to filter my tap water in Hilden?

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.

WaterScore

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

Suggested citation: Trinkwassermonitor (2025): Tap water in Hilden. Values according to the water supplier’s test report, sampling date 2025; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/hilden/

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

Data as of: 2025 · verified: 25 of 25 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 Hilden. Retrieved from https://trinkwassermonitor.ink/en/tap-water/hilden/.”

Further information