Selective removal of metals such as Cu, Ni, Co and Cd from tap water containing small amounts of complexing agents such as humates and salts of carboxylic acid was carried out with a cation-exchange resin possessing a chelating iminodiacetic group. Some of the complexing agents investigated had little effect on leakage, and eluate residues remained below levels permitted for drinking water; other agents (e.g., EDTA) affected the process significantly. Removal of the metals from the resin was successfully performed with 3N HCl or HNO3.