The Safe Drinking Water Act of 1974 as amended in 1986 requires that consumers be notified when maximum contaminant levels are exceeded in their community water supply and when presci-ibed testing and treatment procedures are not met. A review of communication theory indicates that for the message to be effective (1) it must be received by the intended audience, (2) it must be attended to by that audience, (3) it must be understood, and (4) it must be accepted and acted upon. A review and analysis of existing research evaluating notification programs administered under the Safe Drinking Water Act indicates (1) that receipt rates have been highly variable, (2) that attention to the message has usually not been directly assessed, (3) that levels of understanding, while variable, have usually been minimal, and (4) that acceptance, though not often directly measured, seemed higher than expected. These results, while critical of past notification programs, indicate that understanding and