Who supplies the drinking water in Postcode 4057?

Industrielle Werke Basel (IWB). The values shown here come from the supply zone IWB-Wassernetz 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.

Drinking water in 4057 (Switzerland)

One supply zone, water supplier: Industrielle Werke Basel (IWB).

The values come from the SVGW platform trinkwasser.ch. Water utilities report there voluntarily; the SVGW does not verify the data. For each parameter, the minimum, maximum, average and median of one year are published; hardness in French degrees (°fH). On 20 August 2026 the SVGW objected in writing to the use of this data for maunawai.info: we do not show values from this source, but only name the parameters measured there. Analyses we obtained directly from the water supplier are shown in full.

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.

IWB-Wassernetz

Industrielle Werke Basel (IWB)

Assigned via the water supplier — the exact supply zone boundary within the postcode is not yet linked.

Key values IWB-Wassernetz
Parameter	Value	Parametric value	Share of the parametric value	Reference
Escherichia coli (E. coli)	nicht nachgewiesen not detectable Unit not stated in the document	0/100 ml	—	Maximum · IWB-Wassernetz

Show all recorded parameters (4 — most recent value per parameter)

Microbiology (3)

Microbiology – IWB-Wassernetz
Parameter	Value	Parametric value	Share of the parametric value	Reference
Aerobic mesophilic bacteria	27 KbE/ml	300 1/ml	—	Maximum · IWB-Wassernetz
Escherichia coli (E. coli)	nicht nachgewiesen not detectable Unit not stated in the document	0/100 ml	—	Maximum · IWB-Wassernetz
Intestinal enterococci	nicht nachgewiesen not detectable Unit not stated in the document	0/100 ml	—	Maximum · IWB-Wassernetz

PFAS (1)

PFAS – IWB-Wassernetz
Parameter	Value	Parametric value	Share of the parametric value	Reference
Trifluoroacetic acid (TFA)	0.48 µg/L	—	—	Maximum · IWB-Wassernetz

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.bs.ch/original_file/0f3d8c8a3676007d48b2d10dc195b5945300c040/2025-trinkwasser-mik-chem.pdf · 13.04.2026 · 2025 · retrieved on 19/08/2026

Frequent questions about postcode 4057

Who supplies the drinking water in Postcode 4057?: Industrielle Werke Basel (IWB). The values shown here come from the supply zone IWB-Wassernetz 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.