Environmental concerns and government regulations facing the cooling water treatment (CWT) industry have spurred a trend away from chromate-based programs. Polymers are used as components of phosphate-based CWT programs 1) to maintain adequate phosphate concentrations in solution to inhibit corrosion and 2) to prevent fouling. Industry trends and the use of polymers in phosphate-based CWT programs are reviewed. The performance properties of several calcium phosphate inhibitors have been examined and compared with those of new polymeric material.