Tap water quality in Frankfurt am Main

The importance of water quality for health

The quality of the water we consume on a daily basis is crucial to our health. Contaminated water can cause a variety of health problems, from gastrointestinal illnesses to long-term chronic diseases.

It is therefore important to know what substances are in the water and how safe the Tapwater actually is. In this context, regular monitoring and treatment of the water plays a key role in ensuring that it meets the strict legal requirements and is free from harmful substances.¹

Origin and extraction of Frankfurt's drinking water

The Tapwater in Frankfurt am Main comes from a variety of natural sources that characterize the city and its surroundings. The majority - around 70 percent - is extracted as groundwater from the Hessian Ried, Vogelsberg and Spessart regions. These areas, characterized by geological layers such as sandstone and basalt, store large quantities of water that is filtered by natural processes. A smaller proportion comes from the Frankfurt city forest, where wells also supply groundwater. Unlike cities that use rivers such as the Rhine directly, Frankfurt relies on these underground reservoirs to ensure a stable supply.²

Extraction and distribution is in the hands of the utility companies Mainova AG and Hessenwasser, which together operate a network of waterworks. Among the most important are the plants in the Hessian Ried and the wells in the city forest. After extraction, the water is technically treated - for example by aeration or removal of iron and manganese - but remains largely natural, as the groundwater quality is already high. Every year, around 120 million cubic meters of water are provided to supply households, offices and industry in Frankfurt. This regional diversity makes Frankfurt's water special - but it also brings with it differences, for example in hardness, depending on the district.³

Water treatment

Frankfurt's tap water is treated in several stages:

Quality assurance

Before being fed into the network, the water is tested for chemical and microbiological parameters in order to meet the requirements of the German Drinking Water Ordinance. It is then distributed via a 5,000-kilometer pipeline network operated by Mainova.

Ingredients of tap water in Frankfurt

Frankfurt Tapwater contains a natural mixture of minerals that are typical of groundwater. These include calcium and magnesium, which are responsible for water hardness, as well as moderate amounts of sodium, sulphate and chloride. Pollutants such as nitrate are generally well below the legal limits. Heavy metals such as lead are hardly detectable in the public supply network, but can occur in old domestic pipes.

Is Tapwater drinkable in Frankfurt?

The Tapwater in Frankfurt am Main is a topic that interests many - is it really safe? Here is a look at the key aspects.

Legal regulations and limit values

Frankfurt's drinking water is subject to the German Drinking Water Ordinance, which sets strict standards and is based on EU directives. Mainova AG and Hessenwasser regularly monitor it at numerous measuring points for pollutants such as nitrate, heavy metals and germs. According to the suppliers, all legal limits - such as 50 mg/l for nitrate or 10 µg/l for lead - are reliably complied with. However, trace substances such as drug residues or microplastics, which are below these limits, are not tested across the board.⁴

Taste and water hardness

The taste of the water in Frankfurt varies greatly - from soft to hard, depending on the district. With a water hardness of between 4 and 20 °dH, it is often perceived as mineral or "chalky", especially in areas such as the Hessian Ried. This can affect drinking pleasure or coffee quality. In rare cases, such as pipe damage, chlorine is added, which temporarily changes the taste - a point that does not appeal to everyone.

Possible contamination and health effects

The water in the public network is clean, but old house pipes in old buildings in Frankfurt can be weak points. Lead or copper can get into the water here, especially if pipes have not been renovated - a risk that Mainova estimates at around 2-3% of households. Trace substances such as pesticides, hormonal substances or PFAS (per- and polyfluorinated alkyl substances) are also an issue.

According to Hessenwasser and a BUND study from 2024, PFAS, such as trifluoroacetic acid, were detected in traces in Frankfurt's Tapwater - below the limits that will apply from 2026 (0.1 µg/l for 20 PFAS), but these "eternal chemicals" are persistent and could accumulate in the body over the long term.⁵

For sensitive groups such as small children or pregnant women, such substances could raise concerns, even if they are currently considered harmless. The high hardness is harmless to health, but can be harmful to the skin and appliances.

Current cases of drinking water contamination in Frankfurt and the surrounding area

• 22.11.2024 - Water with a chlorine smell until mid-December
  The health authority and Hessenwasser have announced the end of additional chlorination of tap water in the east of Frankfurt.
• 12.09.2024 - Drinking water must be boiled in parts of Heppenheim and Bad Homburg
  Due to contamination with coliform bacteria, residents in some parts of Heppenheim are required to boil their drinking water - for at least ten minutes. These rules also apply in some places in Bad Homburg.
  
• 04.03.2024 - Legionella in Westend: AStA demands rent reduction
  A student hall of residence in Frankfurt has been found to be heavily infested with legionella. AStA Frankfurt is calling for consequences - and not just from the student union.
• 23.04.2024 - PFAS in Frankfurt's drinking water
  An investigation by BUND in April 2024 found PFAS in tap water samples from Frankfurt, including trifluoroacetic acid (TFA). The values were below the EU limit values (0.1 µg/l for the sum of 20 PFAS), but confirm widespread contamination.

These cases are exceptions, but they show that the quality of the house connection depends on the condition of your pipes. If you are unsure, you can use a water filter.

Measures to improve tap water in Frankfurt 

Use of a water filter

The quality of tap water in Frankfurt is already high, but there are ways to improve it even further - for example by using water filters. These offer numerous advantages: they can refine the taste by softening the often perceived "chalky" character caused by water hardness.

In addition, filters contribute to health by filtering out potentially harmful substances such as lead from old household pipes, chlorine (when used temporarily), pesticides or microplastics. This can be a big plus point, especially for households with small children, older people or people with weakened immune systems.

Tips for improving the taste

In addition to using filters, there are simple tricks to optimize the taste of tap water in Frankfurt:

Cool water:
Cold water has a fresher taste and can mask the mineral or chalky aftertaste caused by hard water.

Add lemon slices:
A few slices of lemon give the water a pleasant note and noticeably enhance the taste.

Aerate the water:
Leaving the water to stand for a few minutes allows volatile substances such as chlorine - which is rarely added when pipes are damaged - to escape, which improves the taste.

These measures can not only enhance the taste of Frankfurt's drinking water, but also make it even more pleasant. Further details on water quality can be found on the websites of Mainova AG and Hessenwasser as well as in the drinking water report of the Federal Ministry of Health.

Conclusion: How good is Frankfurt's drinking water really?

The Tapwater in Frankfurt am Main is undoubtedly among the best in Germany - a combination of high-quality groundwater from regions such as the Hessian Ried and Vogelsberg as well as careful treatment by Mainova and Hessenwasser ensures that it meets the strict requirements of the Drinking Water Ordinance. It is safe, rich in minerals and ideally suited for everyday use.

But it is not perfect: depending on the location, the water hardness varies greatly between 4 and 20 °dH and can make the taste seem chalky or mineral, while old house pipes in some old buildings could release lead or copper. In addition, there are trace substances such as PFAS, pesticides or microplastics, which are below the limit values but raise questions for sensitive people or in the long term.

If you want to get the most out of your drinking water - whether for better taste, less limescale in appliances or additional safety - you should consider a water filter. A high-quality filter system can target these weak points and improve Frankfurt's already good water even further. This way, "good" simply becomes "excellent".