The main disadvantage of hard water is?

The main disadvantage of hard water is that it can cause mineral buildup in pipes, appliances, and fixtures, leading to reduced water flow and efficiency. It can also leave behind soap scum and residue on dishes, clothes, and surfaces, making it more difficult to clean. Additionally, hard water can reduce the effectiveness of soaps and detergents, leading to the need for higher amounts to achieve the desired level of cleanliness.

Soap Scum Formation