Switzerland specifically

Swiss tap water for shrimp

Proven hardness values from Swiss supply zones, with source and date of retrieval. And honestly stated where we lack values.

Written by Valentin Fischer, aquarist and operator of Garnelenfischer
Published on 11.09.2026 · Last checked for content on 11.09.2026

Why the zone counts and not the location

Water hardness varies significantly within a single city. In Luzern, the lake water is at 11.7 °fH and the groundwater is at 27.7 °fH, both in the same supply area. In Sion the range is from 12 to 38 °f depending on the zone. Anyone looking for a number for their community is therefore looking in the wrong place: they need the number for their zone.

The cantonal laboratory Zürich explains the mechanism like this: “Communities with a high proportion of groundwater and spring water therefore tend to have hard water, while those with a high proportion of treated lake water tend to have soft water.”

The two units and how to convert them

Swiss water suppliers almost always report total hardness in French degrees of hardness , abbreviated °fH or °f. Aquarium keepers use German degrees of hardness, °dH or °dGH. These are different scales.

Energy Water Bern officially states the conversion factor: “1 degree of French hardness corresponds to 0.56 degree of German hardness.” Energy Thun writes the same thing. The St. Gallen public utilities prove it with a double statement: “16° fH (French degrees of hardness) corresponds to: 9° dH (German degrees of hardness)”.

The values in the right-hand column are converted using the officially specified factor of 0.56 and rounded to whole degrees. The left-hand column gives our care recommendation, not an official value.

Documented values from Swiss supply zones

This table only contains values that the respective water supplier or a cantonal authority publishes itself. We estimated nothing and extrapolated nothing. The unity is that of the source.

How to find your local water hardness

1. Check with the supplier. Almost every Swiss water supply publishes the hardness of its zones. Search for the name of your community plus “water quality” or “water hardness.”
2. About the zip code. The industry association SVGW operates trinkwasser.ch with a search by zip code. Attention: The publication is voluntary, not every supplier takes part, and the SVGW itself writes that it assumes “no responsibility for the correctness of the published data”.
3. Measure yourself. A droplet test for GH and KH costs little and measures what actually comes out of your tap, including the house installation. This is the only value that counts for your tank.

It is best to measure after the water has been running for half a minute and not the first water from a pipe that has been left standing overnight.

What to do if it doesn't fit

Position	What helps
Too soft, below about 11 °fH	Harden with mineral salt for shrimp. Not with tap water from another community, that cannot be reproduced.
Suitable, approximately 11 to 36 °fH	Do nothing. Let the water stand or use water conditioner according to the manufacturer's instructions, done.
Too hard, over about 36 °fH	Blend with osmosis water until the target value is reached. Gradually, not all at once.

This is more important than the absolute value Stability. Shrimp cope well with hard water, but poorly with fluctuating water. If you harden or cut, you have to do this every time you change the water.

The official hardness classification

The Cantonal Laboratory Zürich uses this classification, in French degrees of hardness: «soft (< 15 °fH), over medium hard (15-25 °fH), fairly hard (25-31 °fH) and hard (32-42 °fH) to very hard (> 42 °fH)».

For Neocaridina this means: everything from “soft” to “hard” is generally durable, “very soft” and “very hard” require adjustment.

Sources

All pages accessed on 11 September 2026. The hardness values come from the water suppliers themselves; We reproduce them in their units and have not converted anything except the line expressly marked as conversion.

• City Zürich, drinking water, quality and control: stadt-zuerich.ch
• Municipal utility Winterthur, drinking water: stadtwerk.winterthur.ch
• IWB Basel, facts about drinking water: iwb.ch
• Energy water Bern, water quality, with the conversion factor: ewb.ch
• Energy Thun, water quality: energiethun.ch
• Energy Service Biel/Bienne, water: esb.ch
• ewl Luzern, water quality: ewl-luzern.ch
• SGSW St. Gallen, drinking water quality: sgsw.ch, PDF
• SH POWER Schaffhausen, water: shpower.ch
• SIG Genf, Bilan eau potable: sig-ge.ch, PDF
• AIL SA Lugano, Analisi Acqua: ail.ch, PDF
• Eau de Sion, quality: eaudesion.ch
• Eau de Fribourg, quality of water: eau-de-fribourg.ch
• Viteos Neuchâtel, Fiche eau: viteos.ch, PDF
• Canton Zürich, From soft to hard, with classification and explanation: zh.ch
• SVGW, trinkwasser.ch, search by zip code: trinkwasser.ch

This page does not replace your own measurements. The information provided by your water supplier and the value that you measure in the tank yourself are always binding.