To determine whether water is safe for consumption after it has passed through a water softener and whether there are any health and environmental implications of cationic water softeners.
Sodium concentration was measured in 59 water samples that had passed through a water softener and was compared with the sodium concentration of 5 samples from 4 different local municipal sources.
The mean±SD sodium concentration of softened well water was 278±186 mg/L (range, 46-1219 mg/L). There were 10 (17%) households with sodium levels greater than 400 mg/L. The mean±SD sodium concentration of municipal, nonsoftened water was 110±98 mg/L (range, 0-253 mg/L).
Softened well water in our area on average contained a 2.5-times-higher concentration of sodium than local municipal water, comparable with previous reports. It is unlikely that the increased sodium from softened water would have any health risks for most people. This may not be true for people on severely sodium-restricted diets.Arch Intern Med. 1997;157:218-222