Softening processes all carry a certain monetary expense. In addition, softening can cause several other
problems.
The high pH associated with lime softening tends to favor the formation of hypochlorite as the dominant free
chlorine residual, and hypochlorite is a less powerful disinfectant than other free chlorine residuals. The
high pH may also increase trihalomethane levels in the water. If the water is not properly stabilized after
treatment, then corrosive water may be produced which will corrode the distribution system.
Ion exchange softening, as noted above, can also cause problems due to the high levels of sodium in the
treated water. Both lime softening and ion exchange softening create waste disposal problems.