The most common technology used for removing scale formed by calcium and magnesium ions is ion exchange water softening. A water softener has four major components, a resin tank, resin, a brine tank and valves or controller. When hard water is passed through the resin, calcium, magnesium, and other multivalent ions such as iron adheres to the resin, releasing the sodium ions until equilibrium is reached. A regeneration is needed to exchange the hardness ions for sodium ions by passing a sodium chloride (NaCl) solution (called brine) through the resin.

Acidification/Degasification can be used as a softening process but it has numerous disadvantages, such as handling chemical (sulphuric acid, anti-scalant) and instrumentation for two Ph adjustments. Nanofiltration is sometimes referred to as a softening membrane process and will remove anions and cations. The feedwater requirement for a nanofiltration system is about the same as for a reverse osmosis system and feed water should be pre-treated prior to going to the membranes.