The Biscayne Aquifer is the sole underground source of drinking water for 3 million residents of southeast Florida. It is a highly permeable, wedge-shaped, unconfined shallow aquifer composed of limestone and sandstone. Three Biscayne Aquifer hazardous waste sites on the EPA National Priorities List were addressed as one management unit for the remedial investigation and feasibility study: (1) Miami Drum Site, (2) Northwest 58th Street Landfill, and (3) Varsol Spill Site. These sites are located near each other in north Dade County, Florida. The remedial actions for the three hazardous waste sites are being addressed in four phases: Phase I: Varsol Spill Site--immediate area soil and ground water. Record of Decision (ROD) signed 3/29/85, Phase II: Miami Drum--source control (soils and encountered ground water), completed September 1982. ROD signed 9/13/82, Phase III: 58th Street Landfill--immediate area soil, surface water, and ground water. Enforcement Decision Document (EDD) scheduled Fall 1985, and Phase IV: Study Area Ground Water--ROD signed 9/16/85. The selected remedial action for Phase IV includes adding air stripping to the existing water treatment system in the study area and operating the Miami Springs and Preston municipal wells for the dual purpose of providing potable water and recovering contaminated water from the aquifer. Total capital cost for the selected remedial alternative is estimated to be $5,268,000 with O&M costs approximately $334,400 per year.