To answer this question we will take you deep underground for a geology lesson. Calcium is the 5th most abundant mineral in the earths crust and supplies the building blocks to form hard water.
Limestone Formations and Hard Water
Calcium forms compounds with other elements that produces calcium carbonate or CaCO3, which is Limestone. Limestone is unique because it dissolves into solution when immersed in water becoming a dissolved solid. Water with high amounts of dissolved limestone is referred to as Hard Water. Hard water simply put, is water that is carrying high amounts of rock. Therefore, aquifers with higher limestone concentration produce “Harder” water than aquifers with lower limestone concentrations. Some water supplies have no limestone what so ever. These supplies produce soft water naturally.
How Do You Remove Hard Water?
These dissolved hard water minerals have a positive charge because it has fewer electrons than protons. We called this type of dissolved ion a Cation, or an ion with a positive charge. Water softeners contain a unique filtration media called resin that is negatively charged. Opposites attract. This negatively charged resin media strips the water of the hard water Cation completely removing the hardness minerals from the water supply.