Hard Water: Understand, Measure, and Treat
Hard water affects over 60% of households in France and millions across Europe. Rich in calcium and magnesium, it causes limescale deposits, damages skin and hair, and shortens appliance lifespan. This guide explains what hard water is, how to measure it, and how to treat it without chemicals.
Hard water essentials
What is hard water?
Hard water is water naturally rich in calcium (Ca²⁺) and magnesium (Mg²⁺) ions. These minerals dissolve as water passes through limestone rock underground. Water hardness is measured in French degrees (°f) or German degrees (°dH). Below 15 °f, water is considered soft. Between 15 and 25 °f, it is moderately hard. Above 25 °f, it is hard. Beyond 35 °f, it is very hard. In France, the most affected regions are the Paris Basin, the North, the East, and parts of the South-East, where water can exceed 40 °f. In the UK, London and South-East England are known for very hard water.
The everyday effects of hard water
Hard water has both visible and invisible consequences. On skin, it causes dryness, tightness, and can worsen eczema. On hair, it makes it dull, dry, and brittle. On appliances, limescale deposits clog heating elements, reducing efficiency and cutting appliance lifespan by 30 to 50%. In pipes, scale progressively reduces the diameter, lowering water flow. On energy bills, 1 mm of scale on a water heater increases consumption by 7%. On taps and fixtures, hard water leaves stubborn white marks that require chemical cleaners to remove.
How to measure your water hardness
Three simple methods help you determine your water hardness. First: check our interactive water hardness map by department, based on official data. Second: use TH test strips available at pharmacies or online for a few euros. Third: contact your water supplier or check your water bill, which usually states hardness levels. A result above 25 °f indicates hard water that would benefit from limescale treatment.
Hard water vs soft water: pros and cons
Soft water (below 15 °f) does not produce limescale and is gentler on skin and hair. However, very soft water can be slightly corrosive to copper pipes. Hard water (above 25 °f) contains beneficial minerals (calcium, magnesium) but causes limescale deposits. The ideal solution is to keep the minerals in the water while preventing limescale from depositing — this is exactly what LIMPEO electromagnetic treatment does, unlike a water softener that removes minerals entirely.
How to treat hard water effectively
Several solutions exist for treating hard water. Salt-based softeners remove calcium but add sodium, require regular maintenance, and are expensive (1,500 to 3,000 euros plus ongoing costs). Reverse osmosis filters minerals but wastes significant water. Filter jugs only treat small volumes. LIMPEO chemical-free limescale treatment is the most economical and ecological solution: it does not remove anything from the water but prevents limescale from depositing by transforming calcite into aragonite. Result: 88% scale reduction, zero chemicals, zero maintenance, 5-minute installation.
Frequently asked questions about hard water
Find below the answers to the most common questions about hard water and its treatment.
FAQ — Everything about hard water
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