The unique chemistry of bromine offers distinct advantages over chlorine in many water treatment situations. Understanding where to use bromine chemistry can produce an enhanced water management program. This paper discusses the differences between bromine and chlorine chemistry especially the effects of pH and ammonia. The most common sources of hypobromous acid (bromine, bromine chloride, bromide salts + chlorine, and N-bromo halogen donors) are discussed. New experimental data and a comprehensive bibliography are included.