This paper discusses the process of preparing specifications for chemical treatment of major cooling water systems, evaluating bid responses and operating systems in accordance with specifications. Subjects covered include: proper use of historical operating and performance data; selection of critical parameters and performance standards; the need for flexibility to permit evaluation of alternative proposals; the importance of defined responsibilities for both vendor, and user; evaluation of proposals and selection of vendor, and short and long term accountability for performance in vendor/user partnership after bid has been awarded. Although the paper deals primarily with large electric utility plants, the principles apply well to industrial plants and to other water treatment systems.