A network for monitoring the quality of water in the 13 principal aquifers in Minnesota has been designed and more than 400 wells and springs selected for sampling. The network organization includes four major elements; (1) point sampling, (2) point monitoring, (3) regional monitoring, and (4) site-specific monitoring. These elements constitute monitoring strategies designed to define baseline conditions and monitor major time-and-space trends of more than 60 water-quality parameters.