Environmental information systems are complex computerized networks that merge measuring and information technology. From the users' point of view, measuring accuracy, consistency, reliability, data quality, and efficiency of maintenance, are among their most important features. Several effects may disturb the system characteristics: hostile measuring environment, unreliable communications, unsuitable equipment, or nonqualified personnel. Due to our experiences, a number of measures should be taken to finally achieve the desired system performances. In the paper, we present the analysis of system requirements, possible disturbances and corrective measures, giving the main directives for the design, construction and exploitation of the environmental information systems. Procedures, assuring the data integrity and quality are described. Finally, the contemporary system approach based on the LAN/WAN network topology with Intra/Internet software is proposed.