Tap water in Switzerland: safe to drink, limit values, hardness
Tap water in Switzerland is safe to drink. The maximum value for nitrate is 40 mg/l, which is below the EU value of 50. Values, origin, hardness and filters.
Tap water in Switzerland is safe to drink, from every tap. Food control authorities test more than 50,000 samples a year. In the period 2022 to 2024, 0.55% of nitrate readings were above the maximum value. For fluoride and chromium(VI), the record over 3 years stood at 0 exceedances. The Swiss nitrate value is 40 mg/l. That puts it 10 mg/l below the EU value.
This guide sets out the values in the ordinance and where the water comes from. It also covers 2 groups of substances from the current debate. Here you can read how hard the water is in your municipality, where to find the analysis report and what a filter can do here.
Drinking water flows from every Swiss tap
In Switzerland, drinking water is classed as a foodstuff. Official inspectors test more than 50,000 samples a year. For the period 2022 to 2024, 25 cantons reported data from 3,628 water supplies. They serve 8.6 million people. This covers 96% of the population. The report records drinking water quality on the basis of 2 microbiological and 7 chemical parameters.
The legal basis is the Ordinance of the Federal Department of Home Affairs (FDHA) on Drinking Water and Water in Publicly Accessible Baths and Shower Facilities (TBDV). It came into force on 1 May 2017. Its current version dates from 1 February 2024. The Federal Food Safety and Veterinary Office (FSVO) sets the maximum values. The suppliers carry out self-monitoring. The cantonal laboratories carry out spot checks.
| Parameter | Maximum value | Values above | People affected |
|---|---|---|---|
| Escherichia coli | 0 per 100 ml | 637 of 72,454 (0.88%) | 128,947 (1.5%) |
| Enterococci | 0 per 100 ml | 894 of 72,453 (1.2%) | 241,880 (2.8%) |
| Nitrate | 40 mg/l | 105 of 18,983 (0.55%) | 10,675 (0.13%) |
| Nitrite | 0.1 mg/l | 2 of 12,096 (0.02%) | 7 (below 0.01%) |
| Arsenic | 10 µg/l | 11 of 2,528 (0.44%) | 3,833 (0.06%) |
| Lead | 10 µg/l | 5 of 2,161 (0.23%) | 79 (below 0.01%) |
| Iron | 0.2 mg/l | 35 of 3,140 (1.1%) | 2,284 (0.04%) |
| Fluoride | 1.5 mg/l | 0 of 10,532 | 0 |
| Chromium(VI) | 20 µg/l | 0 of 980 | 0 |
All figures come from the FSVO's sixth report on the Protocol on Water and Health. It was published in 2026 and covers the years 2022 to 2024. Germ findings are short-lived, usually occurring after heavy rain or a fault in the network. The suppliers then flush the pipes. They disinfect with ultraviolet light (UV) or chlorine and, in an emergency, call on people to boil their water. With lead and iron, the cause lies in the network or in the domestic plumbing, i.e. beyond the house connection.
Switzerland sets the nitrate limit at 40 mg/l
The TBDV nitrate value is 40 mg/l. In Germany and the rest of the EU, 50 mg/l applies. Switzerland therefore sets the limit 20% lower. For nitrite, the TBDV specifies 0.1 mg/l. The German Drinking Water Ordinance allows 0.50 mg/l at the tap.
| Parameter | Switzerland (TBDV) | Germany (TrinkwV) |
|---|---|---|
| Nitrate | 40 mg/l | 50 mg/l |
| Nitrite | 0.1 mg/l | 0.50 mg/l |
| Arsenic | 10 µg/l | 10 µg/l |
| Lead | 10 µg/l | 10 µg/l, 5 µg/l from 12 January 2028 |
| Uranium | 30 µg/l | 10 µg/l |
| Chromium | 50 µg/l | 25 µg/l, 5 µg/l from 12 January 2030 |
| Fluoride | 1.5 mg/l | 1.5 mg/l |
| Sodium | 200 mg/l | 200 mg/l |
| Individual pesticide | 0.1 µg/l | 0.1 µg/l |
| Total pesticides | 0.5 µg/l | 0.5 µg/l |
| Sum of 20 PFAS | postponed | 0.1 µg/l since 12 January 2026 |
Switzerland is stricter on 2 values. Germany is stricter on 4, and on 5 the two are equal. A sweeping verdict on the two ordinances therefore does not get you very far. The Swiss nitrate value comes from food law and applies at the tap.
The Waters Protection Ordinance comes into play one stage earlier. For groundwater used for drinking water, it sets a requirement of 25 mg/l. Nationwide, nitrate exceeds this at around one in six monitoring sites. In arable farming areas, the figure is more than 50% of monitoring sites. In drinking water, thanks to blending and switching between water catchments, the value is met in 99.45% of measurements.
80% comes from springs and groundwater
Around 80% of Swiss drinking water comes from spring water and groundwater. Around 20% comes from lake water. In 2024, the water supplies delivered a combined 916 million cubic metres, 1% less than in the previous year. Daily consumption per inhabitant fell from 282 to 276 litres.
The Swiss Gas and Water Industry Association (SVGW) divides treatment into 3 equal thirds.
| Share | Treatment | Typical of |
|---|---|---|
| around one third | fed untreated into the network | Springs in protected areas |
| around one third | 1 stage: UV, ozone or chlorine | Groundwater in the Swiss Plateau |
| around one third | several stages | Lake water |
The minimal treatment follows from the quality of the raw water. Where water comes from a protected area, elaborate treatment is unnecessary. In Austria, the country meets its needs entirely from protected groundwater, and there too it usually reaches households untreated. In Italy, a larger share comes from treated surface water, which is why a chlorine taste is more common there.
Drought shifts the shares from year to year. In 2024, there was a lot of rain, even in summer. As a result, the use of spring water rose by 12%. In the same year, groundwater abstraction fell by 10% and lake water abstraction by 8%.
Zurich, Basel and Geneva get their water in different ways
Zurich draws around 70% of its drinking water from Lake Zurich. Spring water and groundwater each account for 15%. The utility supplies the city and 67 other municipalities and operates 1,282 fountains. Hardness is 14 to 19 French degrees.
| City | Main source | Share | Hardness |
|---|---|---|---|
| Zurich | Lake Zurich, several stages | around 70% | 14 to 19 °fH |
| Basel | Groundwater from the Hardwald and the Lange Erlen | Hardwasser AG around 50% | around 19 °fH |
| Geneva | Lake Geneva | over 80 million m³ a year | hard, high in lime |
| Bern | Groundwater from the Aare valley | mostly | medium hard |
Basel uses a process that is otherwise rare in Switzerland. Hardwasser AG pre-treats Rhine water and lets it seep into the ground in the Hardwald forest. The forest soil filters it further. Wells then pump the recharged groundwater back up. The facilities in the Hardwald and the Lange Erlen together supply around 220,000 people.
In the mountain cantons, the supply looks different. Municipalities there often tap their spring directly, sometimes even without treatment. Origin shapes hardness and taste more than any treatment stage.
Chlorothalonil is the one open issue
Chlorothalonil is a fungicide that was used in arable farming from the 1970s onwards. The Federal Office for Agriculture withdrew its authorisation in December 2019. The sales ban has applied since the beginning of 2020. Since then, the dispute has centred on the breakdown products, technically known as metabolites. In drinking water, the pesticide value of 0.1 µg/l applies to them.
Between 2022 and 2024, 7 metabolites classified as relevant exceeded this value. The metabolite R471811 tops the list by a wide margin.
| Metabolite | Measurements | Values above 0.1 µg/l | People affected |
|---|---|---|---|
| Chlorothalonil R471811 | 3.189 | 979 (31%) | 547,560 (7.9%) |
| Chlorothalonil R417888 | 3.143 | 368 (12%) | 198,913 (2.7%) |
| Chlorothalonil SYN548580 | 82 | 2 (2.4%) | 3,333 (0.37%) |
| S-metolachlor metolachlor-ESA | 2.203 | 43 (2.0%) | 7,867 (0.15%) |
| Chlorothalonil SYN507900 | 1.477 | 12 (0.81%) | 15,667 (0.58%) |
In groundwater, the picture is starker. Nationwide, the contamination affects more than one in four monitoring sites of the National Groundwater Monitoring programme (NAQUA). In the Swiss Plateau, R471811 exceeds the value at over 50% of monitoring sites. 17 cantons report exceedances. Groundwater renews itself slowly, and the metabolites are long-lived. The contamination will therefore persist for years.
The legal battle stretches over 6 years
- 2019 and 2020: The FSVO classifies the metabolites as relevant to drinking water. As a result, the applicable maximum value drops by a factor of 100.
- 2020 and 2021: Following an appeal by the manufacturer Syngenta, the Federal Administrative Court halts individual FSVO directives.
- 20 March 2024: The court rules in favour of the authority in case B-3340/2020. This settles the legal position on the maximum value.
- May 2024: Directive 2024/1 sets out how the cantons are to proceed when values are exceeded.
- 12 March 2026: In case B-531/2020, the court upholds the ban on the active substance. At the same time, it declares 4 metabolites irrelevant, including R471811 and R417888.
The March 2026 ruling carries great weight because it concerns the 2 most widespread metabolites. The judgment was handed down in the authorisation proceedings against the Federal Office for Agriculture. It therefore lies outside food law. On its website, as of 27 July 2026, the FSVO still lists the 2024 judgment as authoritative. For consumers, the maximum value of 0.1 µg/l applies for the time being. As of August 2026, it remains open how the authorities will adjust the classification of plant protection products.
PFAS: the federal government has postponed the new values
For per- and polyfluoroalkyl substances (PFAS), the TBDV currently specifies 3 individual values. Perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate are set at 0.3 µg/l. Perfluorooctanoic acid (PFOA) is set at 0.5 µg/l. From January 2026, a total value of 0.1 µg/l for 20 substances was to be added, plus 0.02 µg/l for a group of four.
On 12 December 2025, the FSVO announced that the change would not go ahead for the time being. It cited the ongoing political debate as the reason. The Council of States' environment committee is calling for Switzerland's own values instead of adopting those of the EU. Experts now expect them to be introduced in 2027.
The Federal Office for the Environment (FOEN) published the situation in groundwater on 27 October 2025.
| Finding | Share of NAQUA monitoring sites |
|---|---|
| PFAS detectable | just under half |
| Sum of 26 PFAS above 0.0044 µg/l | around 25% |
| Sum of 26 PFAS above 0.1 µg/l | just under 2% |
| PFAS in built-up areas | over 90% |
Around 550 monitoring sites were sampled. Germany brought the total value of 0.1 µg/l for 20 PFAS into force on 12 January 2026. The two countries currently differ on the very same figure, and for purely political reasons.
Water hardness is measured in French degrees
Switzerland measures water hardness in French degrees of hardness (°fH). Germany uses German degrees (°dH). 1 °fH corresponds to 0.56 °dH. A value of 25 °fH is therefore equivalent to 14 °dH. If you use a German table, convert using a factor of 0.56.
| Level | °fH | °dH |
|---|---|---|
| very soft | 0 to 7 | 0 to 3.9 |
| soft | 7 to 15 | 3.9 to 8.4 |
| medium hard | 15 to 25 | 8.4 to 14 |
| fairly hard | 25 to 32 | 14 to 17.9 |
| hard | 32 to 42 | 17.9 to 23.5 |
| very hard | over 42 | over 23.5 |
Hardness follows geology. In the Swiss Plateau and the Jura, the subsoil is dominated by limestone. The water there is hard. In the central and southern Alps, crystalline rock dominates, and there the water stays soft. Very soft Alpine water below 7 °fH and Basel at around 19 °fH are 2 hardness levels apart.
Hardness is a purely technical parameter. Calcium and magnesium count as hardness minerals and at the same time as nutrients. Hardness becomes visible as limescale deposits on kettles, taps and washing machines.
Your own value by postcode
3 steps take you to your own values. The SVGW (Swiss Gas and Water Industry Association) runs the trinkwasser.ch platform and makes it available to water suppliers free of charge. Enter your postcode there – the hardness and composition of your water supply will then be displayed. A map leads to the same result. Every water supplier publishes its drinking water quality data, usually also on the municipality's website.
5 values are worth a look, in this order.
| Value | Why it matters | Reference |
|---|---|---|
| Hardness in °fH | determines limescale in appliances | 15 to 25 °fH means medium hard |
| Nitrate in mg/l | measures pressure from agriculture | Maximum value 40 mg/l |
| Chlorothalonil | regionally the most significant finding | 0.1 µg/l per substance |
| Origin | explains taste and hardness | Spring, groundwater or lake |
| Hot water | determines the risk when showering | ask building services |
The supplier's value applies up to the building's service connection. Metals such as lead, copper and nickel only dissolve out of the plumbing after that point. That is why the report says nothing about the domestic plumbing. Having your own measurement carried out by an accredited laboratory is worthwhile if you have a private spring or a domestic well, or if you suspect old pipes. Private water catchments are outside official monitoring. Their owners test the water themselves.
Incidentally, the TBDV also covers water in publicly accessible shower facilities. Where the requirements for the germ count can only be met through structural measures, the deadline runs until 30 April 2027.
Hahnenwasser, eau du robinet, acqua di rubinetto
In German-speaking Switzerland, tap water is called Hahnenwasser, while in Germany it is known as Leitungswasser. In French-speaking Switzerland, people say eau du robinet. In Ticino, it is acqua di rubinetto. All 3 terms refer to the same substance and the same legal situation under the TBDV.
From a health perspective, the data speak in favour of tap water. Over 3 years and 10,532 measurements, the fluoride value of 1.5 mg/l was complied with without exception. The same was true of chromium(VI) in 980 measurements. The FSVO report rates the microbiological quality as very good and stable.
Only Basel ever had fluoridated drinking water
Basel fluoridated its drinking water from 1962 as a precaution against tooth decay. At the end of June 2003, the city discontinued the practice. The reason was a wastage problem. Less than 1% of the fluoridated water ended up in a glass as drinking water. The rest flowed unused into the sewers. Since then, Switzerland has relied on fluoridated table salt, which has been produced industrially since 1955.
Fluoride therefore remains a geogenic trace substance in drinking water. The measured levels are well below the maximum value. If you are looking for your own value, you will find it in your water supplier's analysis report.
What a water filter does in Switzerland
An activated carbon filter binds chlorine, organic trace substances and particles. This improves taste and odour. It works effectively against 2 of the groups of substances discussed here and, by its very nature, not at all against 3 others. Alb Filter's filter elements are based on activated carbon.
| Substance | Activated carbon | Effective method |
|---|---|---|
| Chlorine, taste, odour | effective | Activated carbon |
| Particles and turbidity | effective | Sediment filter, activated carbon |
| Pesticides | partially effective | Activated carbon, reverse osmosis |
| Chlorothalonil | of limited effectiveness | Reverse osmosis |
| PFAS | partially effective | Reverse osmosis, adsorber |
| Nitrate | ineffective | Reverse osmosis, ion exchange |
| Limescale and hardness | ineffective | Water softener |
| Arsenic | ineffective | Adsorber, reverse osmosis |
Chlorothalonil metabolites are highly soluble in water. As a result, they bind poorly to activated carbon. Reverse osmosis, by contrast, works reliably. In the home, however, it requires a fixed installation and produces wastewater. An activated carbon filter makes sense above all where treated lake water has a taste of its own. The second case is the motorhome, where water sits in the tank for days.
The path to a decision leads through the analysis report. If you know the value first and then choose the method, you avoid buying something that misses the actual findings.
Related to this topic
Alb Filter FUSION – activated carbon and Nano filtration combined
The FUSION under-sink drinking water filter combines a sintered activated carbon block with Nano ultrafiltration. Among other things, it reduces chlorine, microplastics, hormones, heavy metals and germs, and leaves the minerals in the water – permanently installed, with no electricity and no waste water.
Frequently asked questions
Can you drink tap water in Switzerland?
Yes. Drinking water is classed as a foodstuff and is subject to the TBDV. Official food control tests more than 50,000 samples every year. Between 2022 and 2024, 99.45% of nitrate measurements and all 10,532 fluoride measurements were within the maximum values.
Can you drink tap water in Zurich?
Yes. Zurich obtains around 70% of its drinking water from Lake Zurich and treats it in several stages. 15% each comes from spring water and groundwater. The hardness is 14 to 19 °fH. The city's 1,282 public fountains also supply drinking water.
What is tap water called in Swiss German?
Hahnenwasser. In French-speaking Switzerland it is called eau du robinet, in Ticino acqua di rubinetto. Legally, all 3 fall under the same ordinance.
Where does Switzerland's drinking water come from?
Around 80% comes from spring water and groundwater, around 20% from lake water. In 2024, water suppliers delivered 916 million cubic metres. Around a third of this volume enters the network untreated, another third after single-stage disinfection.
How much nitrate may Swiss drinking water contain?
The maximum value is 40 mg/l, which is below the EU value of 50 mg/l. For groundwater, a requirement of 25 mg/l applies. Nationwide, around one in six monitoring sites is above this.
How hard is the water in Switzerland?
Geology decides. In the Swiss Plateau and the Jura, the water is hard; in the central and southern Alps, it stays soft. Zurich is at 14 to 19 °fH, Basel at around 19 °fH. 1 °fH corresponds to 0.56 °dH.
Is chlorothalonil in drinking water still an issue?
Very much so. The active substance has been banned since 2020, but its breakdown products remain in the groundwater. Between 2022 and 2024, 979 of 3,189 measurements of the metabolite R471811 were above 0.1 µg/l. This affected 547,560 people.
Does Swiss tap water contain fluoride?
Only geogenic fluoride, i.e. from the rock. Basel was the only city to fluoridate its water, from 1962 to June 2003. Since then, tooth decay prevention has relied on fluoridated table salt. In 10,532 measurements over 3 years, the maximum value of 1.5 mg/l was complied with.
Is tap water in Switzerland unhealthy?
The results of official testing point to the opposite. Over 3 years, 0.55% of nitrate values and 0.44% of arsenic values were above the maximum value. For fluoride and chromium(VI), the number remained at 0. What remains open is how to deal with chlorothalonil metabolites and PFAS.
How do I get my water tested in Switzerland?
You can find the values for your water supply by entering your postcode on trinkwasser.ch. An accredited laboratory analyses a sample of your own. This makes sense if you have a private spring or a domestic well, or if you suspect old pipes in the building.
Does a water filter help against chlorothalonil metabolites?
Activated carbon binds some of the organic residues. With the highly water-soluble metabolites, its effect remains limited. Reverse osmosis works reliably here.
Sources
- FDHA Ordinance on Drinking Water and Water in Publicly Accessible Baths and Showers (TBDV, SR 817.022.11), status as of 1 February 2024, Annex 1 and Annex 2
- Federal Food Safety and Veterinary Office: Implementation of the Protocol on Water and Health in Switzerland, sixth reporting period 2022 to 2024
- Federal Food Safety and Veterinary Office: National targets for water and health, version of 27 February 2026
- Federal Food Safety and Veterinary Office: Directive 2024/1 on chlorothalonil metabolites in drinking water
- Federal Office for the Environment: Groundwater quality and PFAS in groundwater, National Groundwater Monitoring NAQUA, as of 27 October 2025
- Federal Office for the Environment: Chlorothalonil in groundwater, evaluation of the NAQUA monitoring sites
- Federal Administrative Court: judgment B-3340/2020 of 20 March 2024 and judgment B-531/2020 of 12 March 2026
- Swiss Gas and Water Industry Association: Water statistics for the 2024 operating year, published on 20 February 2026
- Swiss Gas and Water Industry Association: Water treatment and the trinkwasser.ch platform
- Wasserversorgung Zürich: Origin and treatment of Zurich's drinking water
- Hardwasser AG and Industrielle Werke Basel (IWB): Groundwater recharge in the Hardwald and the Langen Erlen
- Canton of Basel-Stadt: Switch from drinking water fluoridation to salt fluoridation, announcement from 2003
- Trinkwasserverordnung (German Drinking Water Ordinance) of 20 June 2023 (BGBl. 2023 I No. 159), Annex 2 Part I and Part II
- Waters Protection Ordinance (WPO, SR 814.201), Annex 2
