Drinking water in Aarau
2 supply zones — values can differ depending on the district. Below is the zone with the most documented parameters, the others collapsed underneath. To determine the exact match, look up the postcode.
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.
Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG
Eniwa Wasser AGAssigned via the water supplier — the exact supply zone boundary within the postcode is not yet linked.
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Nitrate | 23 mg/l | 40 mg/l | 57 % | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Escherichia coli (E. coli) | nn not detectable Unit not stated in the document | 0/100 ml | — | Maximum · Median nn · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Sulphate | 16.67 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Sodium | 17 mg/l | 200 mg/l | 9 % | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
Show all recorded parameters (20 — most recent value per parameter)
Microbiology (3)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Aerobic mesophilic bacteria | 6.64 KBE/ml | 300 1/ml | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Escherichia coli (E. coli) | nn not detectable Unit not stated in the document | 0/100 ml | — | Maximum · Median nn · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Intestinal enterococci | nn not detectable Unit not stated in the document | 0/100 ml | — | Maximum · Median nn · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
Chemical parameters (1)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Nitrate | 23 mg/l | 40 mg/l | 57 % | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
Metabolites (2)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Chlorothalonil metabolite R417888 | 0.046 µg/l | 0.1 µg/l | 46 % | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Chlorothalonil metabolite R471811 | 0.208 µg/l | 0.1 µg/l | 208 % Mean above the parametric value | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
Annual means and medians are not individual measured values, but the parametric values apply per sample. If a mean lies above it, at least one individual sample was above it — the mean does not say how many, or by how much. That is why this is not reported here as an exceedance of the parametric value. What counts remains the water supplier's publication, which each row links to.
Indicator parameters (8)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Chloride | 23.87 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Iron | 0.01 mg/l | 0.2 mg/l | 5 % | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Manganese | 0.005 mg/l | 50 µg/l | 10 % | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| pH | 7.33 | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Sodium | 17 mg/l | 200 mg/l | 9 % | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Sulphate | 16.67 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Temperature | 13.5 °C | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Turbidity | 0.11 TE/F | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
Further parameters (6)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Calcium | 102 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Dissolved organic carbon (DOC) | 0.43 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Hydrogen carbonate | 335.33 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Magnesium | 12.27 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Potassium | 3.1 mg/l | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
| Total hardness | 30.43 °fH | — | — | Mean · Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG |
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: 5000
Show 1 more supply zone
Gemeinde Buchs AG
Wasserversorgung Buchs AGAssigned via the water supplier — the exact supply zone boundary within the postcode is not yet linked.
These values are more than a year old. The most recent analysis the water supplier has published for this zone dates from 31/12/2024. We have no newer values — which is why we show the latest available ones rather than none at all. They say nothing about how the water has changed since then.
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Nitrate | 22.37 mg/l | 40 mg/l | 56 % | Mean · Gemeinde Buchs AG |
| Escherichia coli (E. coli) | nn not detectable Unit not stated in the document | 0/100 ml | — | Maximum · Median nn · Gemeinde Buchs AG |
| Sulphate | 15.27 mg/l | — | — | Mean · Gemeinde Buchs AG |
| Sodium | 14.97 mg/l | 200 mg/l | 7 % | Mean · Gemeinde Buchs AG |
Show all recorded parameters (15 — most recent value per parameter)
Microbiology (3)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Aerobic mesophilic bacteria | 15 KBE/ml | 300 1/ml | — | Mean · Gemeinde Buchs AG |
| Escherichia coli (E. coli) | nn not detectable Unit not stated in the document | 0/100 ml | — | Maximum · Median nn · Gemeinde Buchs AG |
| Intestinal enterococci | nn not detectable Unit not stated in the document | 0/100 ml | — | Maximum · Median nn · Gemeinde Buchs AG |
Chemical parameters (1)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Nitrate | 22.37 mg/l | 40 mg/l | 56 % | Mean · Gemeinde Buchs AG |
Indicator parameters (6)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Chloride | 20.17 mg/l | — | — | Mean · Gemeinde Buchs AG |
| Conductivity (25 °C) | 694 µS/cm | — | — | Mean · Gemeinde Buchs AG |
| pH | 7.21 | — | — | Mean · Gemeinde Buchs AG |
| Sodium | 14.97 mg/l | 200 mg/l | 7 % | Mean · Gemeinde Buchs AG |
| Sulphate | 15.27 mg/l | — | — | Mean · Gemeinde Buchs AG |
| Temperature | 13.7 °C | — | — | Mean · Gemeinde Buchs AG |
Further parameters (5)
| Parameter | Value | Parametric value | Share of the parametric value | Reference |
|---|---|---|---|---|
| Calcium | 107 mg/l | — | — | Mean · Gemeinde Buchs AG |
| Dissolved organic carbon (DOC) | 0.36 mg/l | — | — | Mean · Gemeinde Buchs AG |
| Magnesium | 15 mg/l | — | — | Mean · Gemeinde Buchs AG |
| Potassium | 2.83 mg/l | — | — | Mean · Gemeinde Buchs AG |
| Total hardness | 32.83 °fH | — | — | Mean · Gemeinde Buchs AG |
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: 5000
Frequently asked questions about drinking water in Aarau
- How hard is the water in Aarau?
- Eniwa Wasser AG publishes a total hardness of 30.43 °fH for the supply zone Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG — that corresponds to 17 °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: 2025, retrieved on 07/08/2026.
- How much nitrate is in the drinking water in Aarau?
- Eniwa Wasser AG publishes a nitrate value of 23 mg/l for the supply zone Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG. The statutory parametric value is 40 mg/l; the measured value represents 57 % of the parametric value. Basis: 2025, retrieved on 07/08/2026.
- Who supplies the drinking water in Aarau?
- Eniwa Wasser AG. The values shown here come from the supply zone Aarau - Küttigen - Eppenberg-Wöschnau - Erlinsbach AG 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.
No data yet
For postcode 5004 there is no verified assignment yet.