Drinking water in Düsseldorf - Golzheim - Lohausen - Stockum
One supply zone, water supplier: Stadtwerke Düsseldorf.
How to read the share of the parametric value
Several samples per year: for chemical parameters the mean value is given, for microbiological ones the highest measured value. There the parametric value is zero — a single finding would disappear in the average, and it is precisely that finding which is the information. Which reference applies is stated in the last column of the table.
Hochbehälter Hardt (Düsseldorf und Mettmann)
Stadtwerke Düsseldorf| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Sum of PFAS | 0,001 µg/l | — | — | Single value |
| Nitrate | 13,1 mg/l | 50 mg/l | 26 % | Single value |
| Lead | <0,002 mg/l below limit of quantification | 10 µg/l | < 20 % * | Single value |
| Escherichia coli (E. coli) | 0 MPN/100 ml | 0/100 ml | — | Single value |
| Sulphate | 58,2 mg/l | 250 mg/l | 23 % | Single value |
| Sodium | 28,5 mg/l | 200 mg/l | 14 % | Single value |
* Value below the limit of quantification: the actual share of the parametric value is not known; it lies somewhere below the stated upper bound. The marker shows where the limit of quantification of the measurement lies relative to the parametric value.
Show all recorded parameters (64 — most recent value per parameter)
Microbiology (2)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Escherichia coli (E. coli) | 0 MPN/100 ml | 0/100 ml | — | Single value |
| Intestinal enterococci | 0 KBE/100 ml | 0/100 ml | — | Single value |
Chemical parameters (24)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| 1,2-dichloroethane | <0,2 µg/l below limit of quantification | 3 µg/l | < 7 % * | Single value |
| Antimony | <0,0008 mg/l below limit of quantification | 5 µg/l | < 16 % * | Single value |
| Arsenic | <0,0009 mg/l below limit of quantification | 10 µg/l | < 9 % * | Single value |
| Benzene | <0,2 µg/l below limit of quantification | 1 µg/l | < 20 % * | Single value |
| Benzo(a)pyrene | <0,002 µg/l below limit of quantification | 10 ng/l | < 20 % * | Single value |
| Bisphenol A | <0,05 µg/l below limit of quantification | 2.5 µg/l | < 2 % * | Single value |
| Boron | <0,060 mg/l below limit of quantification | 1 mg/l | < 6 % * | Single value |
| Bromate | 0,001 mg/l | 10 µg/l | 10 % | Single value |
| Cadmium | <0,0004 mg/l below limit of quantification | 3 µg/l | < 13 % * | Single value |
| Chromium | <0,001 mg/l below limit of quantification | 25 µg/l | < 4 % * | Single value |
| Copper | <0,030 mg/l below limit of quantification | 2 mg/l | < 2 % * | Single value |
| Fluoride | 0,13 mg/l | 1.5 mg/l | 9 % | Single value |
| Lead | <0,002 mg/l below limit of quantification | 10 µg/l | < 20 % * | Single value |
| Mercury | <0,00001 mg/l below limit of quantification | 1 µg/l | < 1 % * | Single value |
| Nickel | <0,002 mg/l below limit of quantification | 20 µg/l | < 10 % * | Single value |
| Nitrate | 13,1 mg/l | 50 mg/l | 26 % | Single value |
| Nitrite | <0,01 mg/l below limit of quantification | 0.5 mg/l | < 2 % * | Single value |
| Pesticides — Total | <0,01 µg/l below limit of quantification | 0.5 µg/l | < 2 % * | Single value |
| Polycyclic aromatic hydrocarbons | 0 µg/l | 0.1 µg/l | 0 % | Single value |
| Selenium | <0,002 mg/l below limit of quantification | 10 µg/l | < 20 % * | Single value |
| Tetrachloroethene and Trichloroethene (sum) | <0,2 µg/l below limit of quantification | 10 µg/l | < 2 % * | Single value |
| Trihalomethanes — Total | 0 µg/l | 50 µg/l | 0 % | Single value |
| Uranium | 0,0006 mg/l | 10 µg/l | 6 % | Single value |
| Vinyl chloride | <0,2 µg/l below limit of quantification | 0.5 µg/l | < 40 % * | Single value |
* Value below the limit of quantification: the actual share of the parametric value is not known; it lies somewhere below the stated upper bound. The marker shows where the limit of quantification of the measurement lies relative to the parametric value.
PFAS (3)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Sum of 4 PFAS | 0 µg/l | — | — | Single value |
| Sum of PFAS | 0,001 µg/l | — | — | Single value |
| Trifluoroacetic acid (TFA) | 0,50 µg/L | 60 µg/l UBA guide value | 0.8 % | Single value |
For trifluoroacetic acid (TFA), the German Drinking Water Ordinance does not specify a parametric value. The comparison is therefore made with the guide value of 60 µg/l issued by the Umweltbundesamt, which has replaced the earlier health-related guidance value of 3 µg/l. A guide value is not a legal maximum but a health-related classification.
Indicator parameters (20)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Aluminium | <0,030 mg/l below limit of quantification | 0.2 mg/l | < 15 % * | Single value |
| Ammonium | <0,03 mg/l below limit of quantification | 0.5 mg/l | < 6 % * | Single value |
| Calcite dissolution capacity | -6,10 mg/l CaCO3 | 5 mg/l CaCO3 | — | Single value |
| Chloride | 67,9 mg/l | 250 mg/l | 27 % | Single value |
| Clostridium perfringens (including spores) | 0 KBE/100 ml | 0/100 ml | — | Single value |
| Coliform bacteria | 0 MPN/100 ml | 0/100 ml | — | Single value |
| Colony count 22 °C | 1 KBE/ml | ohne anormale Veränderung | — | Single value |
| Colony count 36 °C | 1 KBE/ml | ohne anormale Veränderung | — | Single value |
| Colour | <0,1 1/m below limit of quantification | 0.5 m⁻¹ | — | Single value |
| Conductivity (25 °C) | 699 µS/cm | 2,790 µS/cm | — | Single value |
| Iron | <0,020 mg/l below limit of quantification | 0.2 mg/l | < 10 % * | Single value |
| Manganese | <0,020 mg/l below limit of quantification | 50 µg/l | < 40 % * | Single value |
| Odour | erfüllt - | für den Verbraucher annehmbar | — | Single value |
| pH | 7,50 pH-Einheiten | 6,5–9,5 | — | Single value |
| Sodium | 28,5 mg/l | 200 mg/l | 14 % | Single value |
| Sulphate | 58,2 mg/l | 250 mg/l | 23 % | Single value |
| Taste | erfüllt - | für den Verbraucher annehmbar | — | Single value |
| Temperature | 14,00 °C | — | — | Single value |
| Total organic carbon (TOC) | 0,28 mg/l | ohne anormale Veränderung | — | Single value |
| Turbidity | 0,12 FNU | 1 NTU | — | Single value |
* Value below the limit of quantification: the actual share of the parametric value is not known; it lies somewhere below the stated upper bound. The marker shows where the limit of quantification of the measurement lies relative to the parametric value.
Radiology (2)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Gross alpha activity | < 0,025 Bq/l below limit of quantification | — | — | Single value |
| Radon-222 | < 10 Bq/l below limit of quantification | 100 Bq/l | — | Single value |
Further parameters (13)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Acid capacity to pH 4.3 | 2,00 mmol/l | — | — | Single value |
| Barium | 0,052 mg/l | — | — | Single value |
| Base capacity to pH 8.2 | 0,10 mmol/l | — | — | Single value |
| Bromide | 0,12 mg/l | — | — | Single value |
| Calcium | 1,62 mmol/l | — | — | Single value |
| Hardness range (WRMG) | hart | — | — | Single value |
| Magnesium | 0,36 mmol/l | — | — | Single value |
| Phosphate | <0,07 mg/l below limit of quantification | — | — | Single value |
| Potassium | 3,30 mg/l | — | — | Single value |
| Strontium | 0,453 mg/l | — | — | Single value |
| Thallium | <0,002 mg/l below limit of quantification | — | — | Single value |
| Total hardness | 2,62 mmol/l | — | — | Single value |
| Zinc | <0,010 mg/l below limit of quantification | — | — | Single value |
Values taken unchanged from the publications linked below — for each parameter the most recent recorded value. „—" in the parametric value column: no currently valid legal parametric value is stored in our database for this parameter; the parameter register with all parametric values is being expanded continuously.
Postcodes in this zone: 40474
Frequently asked questions about drinking water in Düsseldorf - Golzheim - Lohausen - Stockum
- How hard is the water in Düsseldorf - Golzheim - Lohausen - Stockum?
- Stadtwerke Düsseldorf publishes a total hardness of 2,62 mmol/l for the supply zone Hochbehälter Hardt (Düsseldorf und Mettmann) — that corresponds to 14.7 °dH. The hardness range is a classification under the German Detergents and Cleaning Products Act (soft below 8,4 °dH, medium 8,4 to 14 °dH, hard above that) and not a quality verdict — it indicates how much calcium and magnesium is dissolved in the water. Basis: Publication by the water supplier, retrieved on 11/07/2026.
- How much nitrate is in the drinking water in Düsseldorf - Golzheim - Lohausen - Stockum?
- Stadtwerke Düsseldorf publishes a nitrate value of 13,1 mg/l for the supply zone Hochbehälter Hardt (Düsseldorf und Mettmann). The statutory parametric value is 50 mg/l; the measured value represents 26 % of the parametric value. Basis: Publication by the water supplier, retrieved on 11/07/2026.
- Who supplies the drinking water in Düsseldorf - Golzheim - Lohausen - Stockum?
- Stadtwerke Düsseldorf. The values shown here come from the supply zone Hochbehälter Hardt (Düsseldorf und Mettmann) and apply to the water the supplier delivers. What happens between the building connection and the tap — in old lead pipes, for example — is not covered by these analyses; information on that is provided by owners, the health authority or an examination by an accredited laboratory.
General questions — how current the data is, limit of quantification, parametric values, who is behind this site — are answered under Questions & answers.