Depth to groundwater ranges from 14 to 27 feet below ground surface, and likely exhibits fluctuation corresponding to the rise and fall of the water level in Apache Lake. Given the topography and the close proximity of the lake, the direction of groundwater flow is presumably dependent upon the elevation of the lake. However, the groundwater elevation contour map generated from data collected during this investigation indicates that groundwater flows to the southeast, away from the lake. Therefore, Apache Lake is characterized as a losing lake.

Waterdog is situated on granitic bedrock and weathered granite. Based on the drilling logs, the local geology consists of approximately 4 to 7 feet of silt and/or sand, underlain by alternating layers of weathered and less weathered granitic bedrock. The bedrock lacks primary permeability but possesses moderate to high secondary permeability due to fracturing.