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Drinking water in Genève

5 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

12 % Share of the parametric value. The proportion of the permitted maximum that the measured value uses — here 12 %, so just over an eighth.
< 10 % * Below the limit of quantification. The substance was not detectable. The mark shows where the detection limit lies relative to the parametric value — the actual share of the parametric value is below that.

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.

Eau du lac

ch-genf

Assigned 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.

Key values Eau du lac
Parameter Value Parametric value Share of the parametric value Reference
Sodium 10,2 mg/L 200 mg/l
5 %
Maximum · Eau du lac
Show all recorded parameters (4 — most recent value per parameter)

Indicator parameters (1)

Indicator parameters – Eau du lac
Parameter Value Parametric value Share of the parametric value Reference
Sodium 10,2 mg/L 200 mg/l
5 %
Maximum · Eau du lac

Further parameters (3)

Further parameters – Eau du lac
Parameter Value Parametric value Share of the parametric value Reference
Calcium 44,4 mg/L Maximum · Eau du lac
Magnesium 5,9 mg/L Maximum · Eau du lac
Potassium 1,7 mg/L Maximum · Eau du lac

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.

Source: https://media.sig-ge.ch/documents/particuliers/eau/bilan_eau_potable.pdf · Avril 2025 · 2024 · retrieved on 08/07/2026

Postcodes in this zone: 1201 , 1202 , 1203 , 1204 , 1205 , 1206 , 1207 , 1208 , 1209 , 1215

Show 4 more supply zones

Eau du lac et nappe de l'Allondon

ch-genf

Assigned 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.

Key values Eau du lac et nappe de l'Allondon
Parameter Value Parametric value Share of the parametric value Reference
Sodium 9,4 mg/L 200 mg/l
5 %
Maximum · Eau du lac et nappe de l'Allondon
Show all recorded parameters (4 — most recent value per parameter)

Indicator parameters (1)

Indicator parameters – Eau du lac et nappe de l'Allondon
Parameter Value Parametric value Share of the parametric value Reference
Sodium 9,4 mg/L 200 mg/l
5 %
Maximum · Eau du lac et nappe de l'Allondon

Further parameters (3)

Further parameters – Eau du lac et nappe de l'Allondon
Parameter Value Parametric value Share of the parametric value Reference
Calcium 78,3 mg/L Maximum · Eau du lac et nappe de l'Allondon
Magnesium 7,2 mg/L Maximum · Eau du lac et nappe de l'Allondon
Potassium 1,7 mg/L Maximum · Eau du lac et nappe de l'Allondon

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.

Source: https://media.sig-ge.ch/documents/particuliers/eau/bilan_eau_potable.pdf · Avril 2025 · 2024 · retrieved on 08/07/2026

Postcodes in this zone: 1201 , 1202 , 1203 , 1204 , 1205 , 1206 , 1207 , 1208 , 1209 , 1215

Eau du lac et nappe du Genevois

ch-genf

Assigned 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.

Key values Eau du lac et nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Sodium 9,4 mg/L 200 mg/l
5 %
Maximum · Eau du lac et nappe du Genevois
Show all recorded parameters (4 — most recent value per parameter)

Indicator parameters (1)

Indicator parameters – Eau du lac et nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Sodium 9,4 mg/L 200 mg/l
5 %
Maximum · Eau du lac et nappe du Genevois

Further parameters (3)

Further parameters – Eau du lac et nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Calcium 57,9 mg/L Maximum · Eau du lac et nappe du Genevois
Magnesium 10,3 mg/L Maximum · Eau du lac et nappe du Genevois
Potassium 2,1 mg/L Maximum · Eau du lac et nappe du Genevois

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.

Source: https://media.sig-ge.ch/documents/particuliers/eau/bilan_eau_potable.pdf · Avril 2025 · 2024 · retrieved on 08/07/2026

Postcodes in this zone: 1201 , 1202 , 1203 , 1204 , 1205 , 1206 , 1207 , 1208 , 1209 , 1215

Nappe du Genevois

ch-genf

Assigned 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.

Key values Nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Sodium 7,1 mg/L 200 mg/l
4 %
Maximum · Nappe du Genevois
Show all recorded parameters (4 — most recent value per parameter)

Indicator parameters (1)

Indicator parameters – Nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Sodium 7,1 mg/L 200 mg/l
4 %
Maximum · Nappe du Genevois

Further parameters (3)

Further parameters – Nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Calcium 66,1 mg/L Maximum · Nappe du Genevois
Magnesium 11,3 mg/L Maximum · Nappe du Genevois
Potassium 1,7 mg/L Maximum · Nappe du Genevois

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.

Source: https://media.sig-ge.ch/documents/particuliers/eau/bilan_eau_potable.pdf · Avril 2025 · 2024 · retrieved on 08/07/2026

Postcodes in this zone: 1201 , 1202 , 1203 , 1204 , 1205 , 1206 , 1207 , 1208 , 1209 , 1215

Zone temporaire Eau du lac et nappe du Genevois

ch-genf

Assigned 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.

Key values Zone temporaire Eau du lac et nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Sodium 9,4 mg/L 200 mg/l
5 %
Maximum · Zone temporaire Eau du lac et nappe du Genevois
Show all recorded parameters (4 — most recent value per parameter)

Indicator parameters (1)

Indicator parameters – Zone temporaire Eau du lac et nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Sodium 9,4 mg/L 200 mg/l
5 %
Maximum · Zone temporaire Eau du lac et nappe du Genevois

Further parameters (3)

Further parameters – Zone temporaire Eau du lac et nappe du Genevois
Parameter Value Parametric value Share of the parametric value Reference
Calcium 66,1 mg/L Maximum · Zone temporaire Eau du lac et nappe du Genevois
Magnesium 11,3 mg/L Maximum · Zone temporaire Eau du lac et nappe du Genevois
Potassium 1,7 mg/L Maximum · Zone temporaire Eau du lac et nappe du Genevois

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.

Source: https://media.sig-ge.ch/documents/particuliers/eau/bilan_eau_potable.pdf · Avril 2025 · 2024 · retrieved on 08/07/2026

Postcodes in this zone: 1201 , 1202 , 1203 , 1204 , 1205 , 1206 , 1207 , 1208 , 1209 , 1215

Frequently asked questions about drinking water in Genève

Who supplies the drinking water in Genève?
ch-genf. The values shown here come from the supply zone Eau du lac 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.