Operation and maintenance of the St. John's Wastewater Treatment Plant incorporates a wide variety of tasks. Purchase of hardware and software was initiated and justified on the premise that overall operation and maintenance efficiency and effectiveness would benefit. This chapter reviews the applications and experiences of a small plant during its first year of using a computer. Plant effluent is regulated by a National Pollutant Discharge Elimination System Permit, which establishes discharge limits, monitoring and reporting requirements and other conditions. In 1983 it was recognized that the volume and complexity of plant activities were increasing. Further review of these activities determined that some were suitable applications for a computer. With the computer identifying equiment, maintaining the histories, and listing scheduled maintenance, the maintenance chief is relieved of most clerical chores. Computerizing various plant functions has not progressed as quickly as anticipated, in hindsight, the time required to become familiar with the hardware and software was underestimated.