Is tap water healthy?
Over 99% of drinking water samples comply with the limit values. When tap water can still cause health complaints and what now applies to lead pipes.
Yes. In Germany, tap water is classed as a foodstuff and is therefore closely monitored. In the 2020 to 2022 reporting period, over 99% of the samples tested met the legal requirements. For the bacterium Escherichia coli (E. coli), the figure was 99.98% of 113,469 tests. Two caveats remain: official measurements end at the water meter, and the owner is responsible for the last few metres inside the building.
This guide clarifies three points with figures rather than reassurances. First, what tap water contains. Second, the documented causes of symptoms after drinking. Third, the four risks beyond the water meter.
What is tap water?
Tap water is drinking water that reaches the home via a water supplier's distribution network. Legally, it is a foodstuff, regulated by the Trinkwasserverordnung (TrinkwV, German Drinking Water Ordinance).
Its origin determines its composition. In 2022, 67.6% of the raw water for the central supply came from groundwater and 15.9% from surface water. The remaining 16.5% came from other resources such as bank filtrate or artificially recharged groundwater. The central supply served 74.1 million people in 2,507 water supply areas, which corresponds to 88.6% of the population.
There are three stages between extraction and the tap. At the waterworks, the supplier treats and tests the raw water. It then travels through the network to the building's service connection. The building's drinking water installation begins at the water meter, and with it the owner's responsibility.
The boundary at the water meter explains most problems. Water that measured clean at the waterworks can still pick up substances over the last few metres.
How good is the quality really?
Every three years, the Umweltbundesamt (UBA, German Environment Agency) and the Bundesgesundheitsministerium (Federal Ministry of Health) publish a report on drinking water quality. The current report was published in 2025 and covers the years 2020 to 2022. It is based on up to 120,000 measurements per parameter and year.
| Parameter | TrinkwV limit | Compliance 2020 to 2022 |
|---|---|---|
| Escherichia coli (E. coli) | 0 per 100 ml | 99,98 % |
| Intestinal enterococci | 0 per 100 ml | 99,89 % |
| Nitrate | 50 mg/l | 99,97 % |
| Copper | 2.0 mg/l | 99,87 % |
| Lead | 0.010 mg/l | 99,49 % |
| Nickel | 0.020 mg/l | 99,49 % |
Two parameters break the pattern, and both are indicator parameters. Coliform bacteria are not pathogens but indicator organisms for hygienic changes in the network. For these, up to 1.2% of samples fell short of the requirements, and for calcite dissolution capacity up to 2.9%. Such a deviation is not in itself a health risk. It indicates that something has changed and triggers further investigation.
For plant protection products, 14 of the 349 active substances and degradation products tested exceeded the limit of 0.10 micrograms per litre in up to 1% of samples. The UBA states that the measured concentrations do not pose a health risk. The limit is deliberately set far below the toxicologically derived threshold.
Nitrate is a frequent source of confusion. Nitrate pollution of groundwater is high in parts of Germany. In drinking water, by contrast, the nitrate limit of 50 mg/l was exceeded in only 6 of 18,790 tests. The waterworks compensate for the pollution, for example by blending with unpolluted water or by relocating wells. Find out more in the guide to nitrate in groundwater and drinking water.
Since 12 January 2026, limits for per- and polyfluoroalkyl substances (PFAS) have also applied for the first time. The details are in the guide to the Drinking Water Ordinance.
Does tap water contain minerals?
Five minerals are regularly present: calcium, magnesium, sodium, potassium and sulphate. How much of each the water contains depends on the region's geology. The TrinkwV sets upper limits for two of them: sodium at 200 mg/l and sulphate at 250 mg/l.
The amounts are rarely relevant to nutrition. Food covers most of the daily mineral requirement. This applies equally to tap water and mineral water.
Calcium and magnesium are deliberately left without a limit because both are harmless to health. These two minerals determine water hardness; find out more in the guide to hard water.
The specific values are provided by the water supplier. Every supplier publishes a drinking water analysis, usually online and sorted by district. The guide to measuring water quality explains how to read the figures.
If you are looking for a direct comparison with bottled water, you will find it in the guide Tap water or mineral water. This article is about the health question itself.
Can tap water cause diarrhoea?
Rarely, and then for a specific reason. For E. coli and intestinal enterococci there is zero tolerance of 0 per 100 ml, met in 99.98 and 99.89% of tests. Three causes are documented, and a fourth is often misattributed. They are listed in order of frequency.
Microbial contamination
Microbial contamination is the case in which tap water actually causes gastrointestinal complaints. If the supplier detects contamination, the health authority orders measures, often a boil-water notice. The supplier must inform the affected households.
So a boil-water notice will reach you; it does not remain a silent finding. Find out more about pathogens and detection methods in the guide to bacteria in tap water.
Sulphate and magnesium
Both have a laxative effect in high concentrations. Magnesium sulphate is better known as Epsom salt. The World Health Organization (WHO) cites a laxative effect for sulphate from 1,000 to 1,200 mg/l. If magnesium and sulphate levels are both high, the effect sets in from around 250 mg/l each, with habituation over time.
The TrinkwV indicator value for sulphate is 250 mg/l. The WHO laxative threshold is four times that. German tap water does not normally reach 1,000 mg/l of sulphate. From around 250 mg/l, sulphate would be noticeable in the taste anyway.
Copper from domestic plumbing
Copper is essential in trace amounts and risky in larger quantities. The Bundesinstitut für Risikobewertung (BfR, German Federal Institute for Risk Assessment) describes upper abdominal discomfort and diarrhoea with excessive intake, and accumulation in the liver with long-term oversupply. Babies and young children are particularly sensitive.
The limit is 2.0 mg/l and was met in 99.87% of tests. In practice, it is only reached with newly laid copper pipes combined with soft, acidic water, and then mainly in stagnant water.
What is often behind it
A change of location brings a different mineral composition and a different microbial flora. The amount you drink and the water temperature also play a role. Both are a matter of habit, not of water quality.
If the symptoms persist or recur, the cause should be investigated by a doctor. A water filter is no substitute for that.
Bloating and flatulence from tap water?
There is no documented evidence that still tap water causes this. The only water-related route would be sulphate above the WHO threshold of 1,000 mg/l, i.e. four times the German indicator value of 250 mg/l. Mains water practically never reaches sulphate levels above 1,000 mg/l.
The most common trigger is in the bottle: carbonation. Carbon dioxide enters the stomach as a gas and escapes again, which is perceived as a feeling of fullness and bloating. Tap water contains no added carbon dioxide.
If you notice flatulence after drinking, first check the type of drink. Sparkling water, spritzers and sugary drinks are more likely culprits than the water from the tap.
Stomach ache, heartburn, nausea
Three symptoms that are often linked to tap water. One figure first: the TrinkwV requires a pH value between 6.5 and 9.5; in practice, values are in the neutral to slightly alkaline range.
Stomach ache can only be explained by water quality in the case of proven contamination, i.e. when there is a boil-water notice, or with elevated copper levels from the domestic plumbing.
Heartburn is caused by stomach acid in the oesophagus. Water with a pH value above 6.5 does not acidify. Carbonated drinks, on the other hand, can promote heartburn. The guide to the pH value of water explains what the pH value tells you.
Nausea after drinking is not a specific sign of water quality. Water is more likely to stand out through its smell and taste, for example a metallic taste with elevated copper or iron levels. For iron, the TrinkwV sets 0.200 mg/l, a value that mainly protects the taste.
There is no such thing as an intolerance to tap water as such. Water contains no proteins, no sugar and no additives for an allergy or intolerance to react to. Anything that presents as an intolerance therefore always has an identifiable cause: a substance in the water, a habit or an illness unrelated to the water.
An unusual taste is a good reason to ask your supplier and have the domestic plumbing checked. A symptom alone is not enough for a diagnosis.
When is tap water unhealthy?
Four risks are real, and all four lie beyond the water meter. Three of them come from the material of the pipes and taps, one from how long the water stands in them. For lead, the legal situation changed fundamentally in 2026, which is why it comes first.
Lead: banned since 12 January 2026
Under § 17 TrinkwV, lead drinking water pipes had to be removed or decommissioned by 12 January 2026. Operators must provide proof of the removal or decommissioning to the health authority. Since 13 January 2026, affected consumers have been entitled to a written statement confirming that the obligation has been met or the deadline has been extended. Violations involving a proven hazard can result in fines of up to 50,000 euros.
Deadline extensions remain possible, for example if the installation company can document capacity bottlenecks or, in narrowly defined exceptional cases, for owner-occupied single-family houses. If a water supply or installation company discovers lead pipes, it must report this to the health authority.
The limit for lead is currently 0.010 mg/l and will fall to 0.005 mg/l from 12 January 2028. Lead acts as a nerve and blood poison and is particularly dangerous for babies, children and pregnant women. Buildings dating from before 1973 are the most affected.
If you live in an older building and don't know about its plumbing, ask the owner or property management in writing for proof. That is the quickest way to get an answer.
Copper and nickel from pipes and taps
Copper pipes release measurable amounts of copper in the first few years after installation, especially with soft water. Chrome-plated taps and components can release nickel; the limit here is 0.020 mg/l. The two limits were met in 99.87 and 99.49% of samples. Details on the individual metals can be found in the guide to heavy metals in tap water.
Stagnant water: the first few seconds
According to the UBA, water that has been standing in the pipes for more than four hours should not be used for drinking or cooking. It may have absorbed substances from the pipe material. Let the tap run briefly until the water feels noticeably cooler on your fingers. This takes a few seconds. The standing water is still suitable for watering flowers.
When it comes to legionella, a clarification is worthwhile. Legionella bacteria multiply between 25 and 45 degrees Celsius and die off above 60 degrees. According to the Robert Koch-Institut (RKI), infection occurs via the airborne route, i.e. by inhaling fine water mist, for example when showering. Drinking is not the route of transmission. The TrinkwV technical action value is 100 per 100 ml.
Nitrate and nitrite
The nitrate limit is 50 mg/l and the nitrite limit 0.50 mg/l. In addition, a sum formula applies: nitrate divided by 50 plus nitrite divided by 3 must not exceed 1. At the waterworks outlet, the threshold for nitrite is 0.10 mg/l.
The reason for the strict rules lies with nitrite. It impairs oxygen transport in the blood, which is particularly relevant for babies.
Tap water for babies and during pregnancy
Tap water is suitable for preparing baby food. Three points should be checked.
First, the plumbing. Water from lead pipes must not be used for baby food. Newly laid copper pipes are also a reason for caution, because babies are sensitive to copper.
Second, the nitrate content. Ask your water supplier, the health authority or your municipality for the value for your district. Exceedances are rare; most suppliers are well below the limit of 50 mg/l.
Third, boiling. As a rule, it is not necessary. If you want to rule out germs at the tap, boil the water during the first weeks of life and let it cool to 30 to 40 degrees Celsius.
And a word on honesty: for baby food, the Verbraucherzentrale (German consumer advice centre) explicitly does not recommend a water filter, because filters can themselves become a source of germs. This applies in particular to filter jugs, in which water stands for hours. The guide to the risk of bacterial growth in filter jugs explains the background.
The same logic applies during pregnancy. The mains water is safe; the risk factors lie in the domestic plumbing. A detailed assessment can be found in the guide to tap water during pregnancy.
When a water filter makes a difference
Viewed objectively: what the supplier already takes care of, a filter does not do any better. Treatment at the waterworks uses processes that are not available in the home. On top of that come up to 120,000 measurements per parameter and year.
The sensible area of use lies beyond the water meter. That is where official monitoring ends, and that is where the problems described in this guide arise.
Taste and dissolved substances are the domain of an activated carbon block. The Alb Filter Active cartridge works with a pore size of 10 micrometres. According to the manufacturer, it adsorbs chlorine, chlorinated hydrocarbons, pesticides, pharmaceutical residues and hormones; lead and copper are also listed. Its service life is 4 months or 3,000 to 5,000 litres. The product page does not state reduction rates according to a test standard.
Germs require a different process. Bacteria measure between 0.5 and 5 micrometres and pass through a 10-micrometre structure. This is where the Nano cartridge comes in, with a hollow-fibre membrane of 0.1 micrometres. It was tested according to ASTM F838-15A, a standard of the American Society for Testing and Materials (ASTM). According to the test report, it retains 99.999% of germs and bacteria, including legionella, Vibrio cholerae and E. coli. According to the manufacturer's own comparison table, it does not filter chlorine or heavy metals.
The limitations are just as important. A filter does not replace the renovation of lead pipes, it does not lift a boil-water notice, and it does not treat symptoms. It also needs maintenance: an overdue cartridge change turns the filter into exactly the problem it is meant to solve. The guide to activated carbon filters for water explains how activated carbon works and where its limits lie.
Safe at the waterworks, the home is what counts
In Germany, tap water is safe for health, and that is a question of measurement, not of trust. Over 99% of samples comply with the limits; for E. coli, the figure is 99.98% of 113,469 tests.
The remaining risks share a common address: the domestic plumbing. Lead has been banned since 12 January 2026, copper and nickel are a question of material and standing time, and stagnant water can be run off in a few seconds.
The water rarely explains symptoms after drinking. A boil-water notice comes via the supplier, high sulphate levels can be tasted, and carbonation comes from the bottle. If things remain unclear, the next step is a doctor, not a filter.
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
Is it healthy to drink tap water every day?
Yes. As a foodstuff, tap water is approved for long-term consumption and is monitored with up to 120,000 measurements per parameter and year. The prerequisite is domestic plumbing without lead pipes.
Is tap water harmful?
As a rule, no. It becomes harmful through substances from the domestic plumbing, above all lead, or through microbial contamination, which then triggers a boil-water notice. In the 2020 to 2022 reporting period, over 99% of samples complied with the limits.
Can you get diarrhoea from tap water?
Rarely, but it is possible. Documented causes are microbial contamination, sulphate above 1,000 mg/l and elevated copper levels from new copper pipes. The sulphate indicator value of the German Drinking Water Ordinance is 250 mg/l, i.e. well below the laxative threshold.
Can tap water cause flatulence?
There is no documented evidence that still tap water causes this. Flatulence after drinking is usually due to carbon dioxide, which enters the stomach as a gas. Tap water contains no added carbon dioxide.
Is tap water carcinogenic?
No. Substances assessed critically are nitrate, which can form nitrite and then nitrosamines in the body, and chromium. The limits are 50 mg/l for nitrate and 0.025 mg/l for chromium, which will drop to 0.005 mg/l from 12 January 2030. The nitrate limit was exceeded in 6 of 18,790 tests.
Is tap water healthy for babies?
Yes, provided the domestic plumbing is free of lead pipes and no new copper pipes have been laid. The water supplier can tell you the nitrate value. Boiling is not necessary, but it is possible during the first weeks of life; then let the water cool to 30 to 40 degrees Celsius.
Is hard tap water healthy?
Yes, just as healthy as soft water. Limescale consists of calcium and magnesium, and the Drinking Water Ordinance sets no limit value for either. A high limescale content increases water hardness and puts a strain on appliances, not on your health.
How can I tell whether my tap water is contaminated?
Three steps lead to the answer. The water supplier's drinking water analysis shows the values up to the building's service connection. The year of construction and the pipe material clarify the risk inside the building; for buildings dating from before 1973, this includes testing for lead. The values at your own tap require sampling by an approved testing laboratory.
Sources
- Umweltbundesamt (German Environment Agency) and Bundesministerium für Gesundheit (Federal Ministry of Health): Bericht über die Qualität des Trinkwassers in Deutschland 2020 bis 2022 (report on drinking water quality in Germany, 2020 to 2022), series Umwelt und Gesundheit 03/2025
- Trinkwasserverordnung (TrinkwV, German Drinking Water Ordinance) of 20 June 2023, § 17 and Annexes 1, 2 and 3
- World Health Organization: Sulfate in Drinking-water, background document for the Guidelines for Drinking-water Quality
- Robert Koch-Institut: RKI-Ratgeber Legionellose (RKI guide to legionellosis)
- Bundesinstitut für Risikobewertung (German Federal Institute for Risk Assessment): Aufnahme von Kupfer, in Spuren lebensnotwendig, in grösseren Mengen riskant (copper intake: essential in traces, risky in larger amounts)
- Umweltbundesamt: Trinkwasser-Installation, auf die letzten Meter kommt es an (drinking water installations: the last few metres matter)
- Verbraucherzentrale (German consumer advice centre): Eignet sich Leitungswasser für Babys? (Is tap water suitable for babies?) and Bleileitungen verboten, Leitfaden zum Austausch von Bleirohren (lead pipes banned: guide to replacing lead pipes)
