Limescale deposits and limescale in drinking water are a highly controversial topic for many people. False rumors about limescale are constantly circulating. But which of these are actually true? How does limescale actually form? And what are the disadvantages of a high limescale content? In this guide, we provide answers to these questions and provide an overview of the various methods for treating and removing limescale: Limescale Removal – The Guide to Limescale-Free Water.
How does limescale form in water?
Limescale is a common term for calcium carbonate – a compound of calcium, carbon, and oxygen. The proportion of dissolved limescale in water defines its "hardness." In Germany, water is classified as soft, medium, and hard. These three so-called hardness ranges are defined by the amount of calcium carbonate they contain:
- Hardness level I – soft water: has 0 to 1.5 millimoles of calcium carbonate per liter, meaning the hardness is between 0 and 7 °dH. The unit °dH is an abbreviation for "degree of German hardness."
- Medium water: The hardness of medium water is between 8 and 14 °dH.
- Hard water: contains more than 2.5 millimoles of calcium carbonate, i.e. a hardness above 14 °dH.
But how do these different lime levels arise? And what do they mean for drinking water quality?
After precipitation such as rain or snow, the water seeps into the ground and eventually becomes groundwater. Minerals present in the soil dissolve in the water during this process. The minerals calcium and magnesium are also called hardness-forming minerals because they determine the water's hardness. The more of these minerals dissolved in the water, the harder the water.
This is how limescale is formed and this is the hardness of calcareous water:
Limescale is formed when calcium and magnesium react in water. Limescale is water with a high degree of hardness, or hard water. Limescale can affect many household appliances, such as washing machines and kettles. There are various solutions for removing or filtering limescale from drinking water. More on this later.
What is the problem with limescale?
When hard water is heated, the hardness-forming substances precipitate and form solid deposits – the familiar limescale. Furthermore, hardness-forming substances bind soap (=limescale soap), so you need to use more soap. Since the limescale remains even after evaporation, it can cause several problems in the home that you would rather avoid. These problems and inconveniences are caused by limescale:
- High levels of limescale = high energy consumption , more wear and tear : Some appliances (e.g. heat exchangers) can work less efficiently if they are limescaled. If a heat exchanger is limescaled and the limescale is not removed, the energy consumption increases over time. Limescale deposits in the water therefore lead to a larger ecological footprint due to the high energy waste. Sensitive appliances such as expensive espresso machines or washing machines and dishwashers therefore usually have an integrated water softener in this country. And yet their lifespan is shorter than with soft water! Many people therefore want a water filter that reduces the high water hardness - more on this later!
- Rapid bacterial growth: The risk of biofilm (harmful microorganisms) forming on surfaces is higher with limescale than without. Legionella bacteria settle on suitable surfaces as slimy substances. Limescale is a very popular place for colonization. In heavily calcified water systems, contamination can occur more quickly and extensively.
- Altered taste: When preparing tea or coffee, taste is an important component that contributes to enjoyment. However, if the water contains a lot of lime, the limescale can neutralize the flavors. As a result, these beverages quickly lose their distinctive taste. Furthermore, limescale causes streaks to form on the surface of hot beverages, such as the typical tea skin on black teas. These are unsightly and easily avoidable. Furthermore, these hardness-causing substances destroy the valuable phenols in healthy teas.
- Stained residue: A well-known problem with limescale is the staining of tiles and fixtures, cooking utensils, and dishes. When limescale builds up on such surfaces, it leaves white spots and sometimes even crusts. These types of residues are not only visually unsightly but also difficult to remove. In fixtures, these encrustations attack seals, leading to premature malfunctions and leaks. Often, the entire fixture must be replaced.
While only a central water softener at the house connection can help with water in the bathroom and for permanently connected appliances, limescale problems in the kitchen (cooking, drinking, and washing up) can be easily solved with a suitable water filter . Reverse osmosis systems, such as the classic built-in version ROWA Economy, reduce hardness-forming substances in drinking water by approximately 95%.
Please note: Activated carbon filters do NOT remove limescale! The familiar pitcher filters with activated carbon do not filter out limescale, but they do soften water through additional ion exchange: a chemical-physical process in which certain ions are exchanged for others on a resin surface. Usually: calcium and magnesium out – sodium in.
Many people are probably wondering whether the consumption of lime not only causes the problems mentioned above, but also has a potential impact on health.
We can reassure you for now: Drinking hard water is completely harmless from a health perspective! The minerals that make up limescale (calcium and magnesium) are not harmful to us humans; in fact, they are actually beneficial! Calcium strengthens teeth and bones. Magnesium is good for cell function and plays an important role in our muscles. However, these minerals are present in drinking water in inorganic form – fresh foods, on the other hand, provide them in an organically bound form that the human body can use directly. Therefore, you should not assume that you can cover your calcium and magnesium requirements by drinking hard water. We definitely do not need hard water to get our daily dose of minerals; rather, we need a balanced diet that provides not only calcium and magnesium but also all other important minerals and trace elements in appropriate forms.
- Hard water, therefore, isn't harmful to our health, but it also doesn't offer any health benefits. Therefore, soft and pure water (water with little to no hard water content) is still best, as it helps you avoid all the other problems mentioned above.
How do I remove limescale from water?
If you want to remove limescale from your water so you can enjoy pure, soft drinking water, you have several options. Here, we'll show you which options are the most practical and which are less practical:
Boil water: When water is boiled, limescale builds up on the inside of the pot or kettle. If you want to drink small amounts of water, for example, for tea or coffee, you can boil the water beforehand to remove limescale. To do this, boil the water in the pot or kettle for several minutes. Then pour the boiling water through a coffee filter to filter out the limescale. Repeat the process to remove as much limescale as possible.
- This method is only suitable for small amounts of water and takes some time, as the water has to run through the coffee filter two or three times. It also consumes a considerable amount of energy. Efficiency: 6/10.
Household descaling products: If you have vinegar or vinegar essence on hand, you can use them to effectively remove limescale deposits on faucets. Different types of vinegar require different dosages. For regular vinegar, mix one part vinegar with one part water (1:1). For vinegar essence, the dosage is 1:4, where one part vinegar essence is mixed with four parts water. You can now use the prepared mixture to remove limescale residue from your sink or washbasin. Soak the areas for about 15 minutes, then rinse thoroughly. Your faucets will look like new again!
- This method is well-suited for external cleaning and removing limescale deposits. However, it doesn't remove limescale from the water itself! Efficiency: 5/10.
Caution: For sensitive surfaces or seals, we recommend using citric acid instead of vinegar, as it is less aggressive towards materials.
Baking soda for dissolving: Another product you might have at home is baking soda. This powder is typically used for baking, but in this case, it also works great as a descaling agent. Simply add a pinch of baking soda to boiled water (from the kettle). The baking soda will descale the water and provide a short-term, limescale-free solution similar to boiled water.
- This removal method is more suitable for traditional coffee breaks than for the entire water supply. Efficiency: 4/10.
Dissolving tablets: You can purchase tablets to remove all types of limescale from coffee machines, teapots, and kettles. Simply dissolve the tablet in the desired appliance and then bring it to a boil. For maximum effectiveness, rinse the appliance thoroughly several times after use.
- Tablets clean your household appliances and keep them free of limescale. However, each tablet is individually wrapped, and thorough cleaning requires frequent use. This method leaves the water hard, and the problem of hard water is not solved. Efficiency: 3/10.
Water filter: To ensure limescale-free water straight from the tap, install an under-sink filter at home. But be careful: Not all water filters are suitable for producing soft water, as the focus is often on harmful substances or even simply on taste and odor.
A truly reliable process is reverse osmosis . It removes limescale using a membrane that allows only the smallest water particles to pass through. This allows a reverse osmosis system to filter out not only limescale, but also all harmful substances such as heavy metals or pharmaceutical residues, which are otherwise difficult to completely eliminate.
In principle, other under-sink filters can also soften water, for example, if they have a filter stage with an ion exchanger . This chemically softens the water and replaces the magnesium and calcium ions with other ions. However, the water is then significantly contaminated with (usually) sodium. Due to the high water hardness in Germany, portable filter stages are often only effective for a few weeks before the material needs to be regenerated or replaced. We at H2O therefore only recommend this process in special cases.
Physical hardness stabilization methods such as magnetic, electromagnetic or current pulse processes are also intended to control water hardness – however, these processes are only suitable for domestic water connections and, in our experience, can only be considered to be partially effective.
- Reverse osmosis and ion exchange water filters provide soft water directly from the tap. Easy to install, water filters are the best solution for truly filtering limescale directly from the water. Feel free to consult our specialist staff or check out our selection on our website. Efficiency: 10/10.
Comparison of water filters for removing limescale
As explained above, special water filters are the most reliable and effective way to remove limescale from your drinking water at home. However, not every filter can remove limescale from tap water, and there are differences even within a group of filter types using the same filtration process. Here you'll find an overview of the different water filters and what they can filter.
The differences between activated carbon block filters and reverse osmosis systems
Activated carbon block filters: This type of filtration is not suitable for removing limescale from tap water. This is because dissolved calcium carbonate is far too small for the mechanical filtration of activated carbon – it simply "slips" through the pores completely unhindered! And since these molecules do not have a particularly strong charge, they do not attach to the large internal surface of activated carbon and remain in the water after filtration. Activated carbon filters are therefore more suitable for removing pollutants such as pesticides, heavy metals, chlorine, or microorganisms of any kind. You can see what each system can filter from the diagram below.
Reverse osmosis systems : Unlike activated carbon filters, reverse osmosis systems can remove limescale and all other contaminants from the water. This filtration process works by using an extremely fine-pored, cross-linked membrane in the filter, which only allows tiny water particles to pass through. Therefore, ALL contaminants and all dissolved substances (salts/minerals, small organic compounds) can be filtered out of the water (see diagram below). Check out our bestseller, the H2O Economy, in our online shop for inspiration.
What are the areas of application for lime-free water?
If you've opted for a filtration process and reduced the limescale content in your drinking water, there are several ways to use the soft water. We've compiled a list of applications where using limescale-free water is worthwhile:
Plants: Water is an important nutrient for plants, just as it is for us humans. In nature, plants receive rainwater, which is generally soft (i.e., limescale-free). However, if you have houseplants and water them with tap water, the water may be very hard and calcified. So, filter the water for your plants as well, to do them a favor! If you use an under-sink filter, like the H2O Economy, at home, you'll automatically get soft, limescale-free water straight from the tap.
Food preparation: Limescale-containing water can significantly impair the taste because it contains high levels of calcium and magnesium ions. This impairment is particularly noticeable when making tea or coffee. Even when cooking with water, the taste, color, and freshness are not fully appreciated. To prevent this from happening, a water filter is a good option, as it reliably removes any limescale from the water. A reverse osmosis system, which connects directly to the water supply, even provides filtered water directly from the tap! Feel free to contact us for advice, or check out our range on our website.
Conclusion
Hard water does not pose a health risk per se. However, there are good reasons why you should remove limescale from your tap water. We have presented and explained various filter options for you. Ultimately, the decision is yours. Above all, it depends on what you use your tap water for. If you use it for cooking, drinking, watering, etc., an under-sink filter connected directly to the water pipe is a good option. However, if you only use your drinking water for making tea or coffee, you can also use another, short-term filtering method. For soft water throughout your household, you will need to invest in a water softener or physical limescale treatment at the house connection. Nevertheless, water filters are a good choice because, in addition to limescale, they also filter out many other pollutants from drinking water, such as heavy metals or pesticides. You can find a comprehensive range of water filters for your home on our website.
We are happy to advise you and are always open to questions on the topic.
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