A system or equipment called a water softener is used to remove minerals from water, typically calcium and magnesium ions. We refer to the process of eliminating these minerals as "water softening." In regions where the water supply is regarded as "hard," or has significant amounts of calcium and magnesium ions, water softeners are frequently utilized. Beads of resin coated in sodium ions are found in the water softener. A structure called a retention tank—also called a detention tank or retention basin—is used to manage and hold off stormwater runoff. It is a component of stormwater management systems that regulate water flow, prevent flooding, and reduce the likelihood of erosion and water pollution. In metropolitan locations where impermeable surfaces such as buildings and roads hinder the natural absorption of rainfall, retention tanks are frequently utilized.