Abstract: The instant invention is directed to a process for inhibiting corrosion and the formation and deposition of scale in aqueous systems, comprising adding to the system at least 0.1 ppm of a water-soluble polymer having an intrinsic viscosity of 0.05 to 2.5, prepared from:(a) 50 to 90%, by weight, of an unsaturated carboxylic acid, or its salt;(b) 5 to 40%, by weight, of an unsaturated sulfonic acid, or its salt; and(c) 5 to 40%, by weight, of an unsaturated quaternary ammonium compound.The instant invention is also directed to a water soluble polymer, having an intrinsic viscosity of 0.05 to 2.