Some of the old-style water softening systems increased the salt content of the water connected to the device, which complicated (or had the potential to complicate) resident health issues. Consequently, the State of Missouri’s construction standard regulation 19 CSR 30-85.012(117) states that, “Water softeners, if used, shall be connected to the hot water supply only or connected so that water used for cooking and drinking is not softened.”
Dave’s Memo: This regulation has not been updated, so it is somewhat dated, and newer technology may have resolved the above mentioned issues. Please refer to manufacturer guidelines when installing any equipment as a good rule of thumb. If a facility chooses to utilize an updated system that doesn’t increase the salt content of the water, the Department of Health and Senior Services is able to issue an exception to the regulation permitting the installation of a water softener to a cold water line. Current regulations only permit a water softener on a hot water line (or water not used for cooking and drinking); therefore, an exception must be requested to install a softener on your cold water lines that could be used for cooking and drinking.