Yes, it's true. There may be several reasons for this, and if you already suffer from skin conditions such as eczema, you will be far more sensitive to these.

Contributing factors include taking showers (or baths) that are too hot, causing the destruction of your natural skin oils. It could also be down to your shower water being either too acidic or too alkaline, so detergents and soaps don't dissolve and wash off properly. 

If your water is hard, due to high levels of calcium and magnesium ions, it makes it too alkaline. Consequently, it can increase your skin alkalinity, causing damage to your skin barrier. In its weakened state, it becomes more sensitive to inflammation and irritation, and also more prone to infection.

A 2017 study found that the combination of a genetic predisposition and exposure to hard water may contribute to the development of eczema.

Along with toxins in our water from medication, chemicals and heavy metals, another major skin irritant is chlorine.