Knowledge of the depth to the water table is useful to State and local officials in making decisions on land use in the rapidly urbanizing greater Denver are. This report presents the results of a 2-year investigation to determine the depth to the water table, water-table fluctuations and trends, and to relate the results of the investigation to urban planning in the greater Denver area. The report is one of a series of geologic and hydrologic reports prepared by the U.S. Geological Survey to demonstrate the usefulness of Earth-science information in urban planning.