Question 1

How do I read the world map?

Accepted Answer

Each country is coloured according to its water hardness level, from softest to hardest. Highlighted countries have a detailed region-by-region map: click one to zoom in and explore local values. You can change the hardness unit shown at any time using the switcher above the map.

Question 2

Why are some countries shown in grey?

Accepted Answer

Grey means we don't yet have verified hardness data for that country. We'd rather show nothing than approximate values. Coverage expands gradually, country by country, as reliable sources are validated.

Question 3

Which units is hardness shown in?

Accepted Answer

Hardness can be displayed in French degrees (°f), German degrees (°dH), English degrees (°e), parts per million (ppm, equivalent to mg/L of CaCO₃), grains per gallon (gpg), or millimoles per litre (mmol/L). The unit switcher converts the whole map instantly, so you can compare one country with another even when their default units differ.

Question 4

Where does the data come from?

Accepted Answer

Values rely first on each country's official water regulators and bodies (health agencies, water utilities, public services), supplemented by UNEP's international GEMStat database where relevant. The exact sources and method are listed on each country's detailed map, along with a confidence level and an update date.

Question 5

What is the difference between a salt-based softener and LIMPEO?

Accepted Answer

A salt-based softener removes calcium through ion exchange and adds sodium to the water. It requires salt (100-300 kg/year), regular maintenance, and discharges briny wastewater. LIMPEO modifies limescale crystallisation through an electromagnetic field: no salt, no chemicals, no maintenance, no wasted water. The water retains its beneficial minerals.

Question 6

What should I do if my water is hard?

Accepted Answer

If your region shows up as hard or very hard, an anti-limescale treatment protects your pipes, water heater, and appliances and cuts your energy use. The LIMPEO electromagnetic device works across the entire hardness range, with no salt, no chemicals, and no maintenance. It is manufactured in France by MAGIIC SAS and backed by a 10-year repairability commitment.

Water hardness map of United States

Interactive map — United States

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Water hardness by state: United States