The Biscayne aquifer is the source of all fresh ground water in the Oakland Park area of eastern Broward County, Florida. This aquifer extends from the land surface to more than 215 feet below mean sea level and is composed chiefly of sandy marine limestone, calcareous sandstone, and beds of fine to medium quartz sand. The aquifer differs from place to place, but, in general, most of the layers of limestone and sandstone occur at depths below 60 feet. The permeability of the aquifer increases with depth.