How much calcium does the water in your city have?

In Spain, when we talk about filtering shower water, we are mainly talking about limescale. Limescale is the calcium and magnesium dissolved in the water. The more minerals it contains, the “harder” it is.

Where is the water hardest in Spain?

The OCU analyzed tap water in dozens of municipalities and classified it by hardness in French degrees (ºf). According to the results published in 2023:

• Very hard (more than 40 ºf): Zaragoza, Teruel, Valencia, and Almería.
• Hard (up to 40 ºf): Tarragona, Murcia, and Jaén.
• Soft: cities such as A Coruña, León, Valladolid, Burgos, and Madrid.

In other words, a large part of the Mediterranean coast and the Ebro Valley has hard or very hard shower water.

Is it bad for your health?

For drinking, no. The World Health Organization does not set a hardness limit for drinking water. Where it is noticeable is on the outside: limescale leaves deposits on shower screens and taps, as well as on the skin and hair. We explain this in the following articles.

Sources

• OCU, analysis of tap water in Spain: ocu.org
• Summary of the hardness classification (The Objective, 12/06/2023): theobjective.com