Which type of water is often referred to as hard water?

Hard water is characterized by a high mineral content, primarily calcium and magnesium ions. Well water is often considered hard water because it is sourced from underground aquifers where it can absorb various minerals as it travels through rocks and soil. This mineral content can vary significantly depending on the geological composition of the area surrounding the well.

Rainwater, while usually soft, can still become hard if it collects minerals after falling to the ground. Distilled water, on the other hand, is produced through distillation, which removes minerals and impurities, making it very soft. Similarly, reverse osmosis water has undergone a filtration process that eliminates many minerals, resulting in soft water. Thus, well water stands out as the correct choice since it is frequently high in hardness due to its natural mineral content.