Mineralized water combined with soap scum and calcium and magnesium can discolor shower stalls, toilets and create etching on glass shower doors. It’s called scale buildup and it is very difficult to clean and keep clean. Hard water can also cause hair loss or lead to thinning hair and dandruff. The minerals in your water destroys your hair follicles and weakens the hair stands causing breakage.
The same happens to your appliances including your hot water tank and pipes. With major buildup of scale will cost you more in the long run than a residential water purification system. This is the only way to stop scaling in your water.
You could buy a descaler water system to help remove the residue and damage already done to your home and prevent further damage. If you are trying to remove scale buildup on your own you could try vinegar or lemon juice. It’s acid so don’t apply it on gold plumbing fixtures.