The data and network operating procedures from the precipitation and snow sampling networks in the AOSERP area of Alberta were reviewed and assessed. The data was first reformatted into NAQUADAT format and then quality assured by several screening procedures including outlier tests, simultaneous high concentration tests, and anion/cation ratios. A computer tape for the reformatted and screened data was produced. The data were also analysed statistically by factor analysis and other procedures to determine its reliability and level of confidence. A major deficiency found was the poor and highly variable collection efficiency for precipitation data which precluded conducting any detailed analysis. Since the determination of the environmental impact of two major pollution sources on precipitation quality in the study area was a primary project objective, poor collection efficiencies did not permit satisfaction of this objective. Extensive evaluation was also made of the operational procedures for both the field and laboratory methods. While laboratory methods were generally found to be adequate in the later years (1983, 1984), field procedures, particularly the method of sampling, were determined to be inadequate to meet the operational objectives of the network. Other major deficiencies were the absence of a documented quality assurance plan, the generally low level of quality control in network operations, and a poor level of documentation for all aspects of network operation. These factors limited the ability to perform a comprehensive evaluation of the data. Recommendations for mitigating these problems are suggested in the report.