Where Florida's drinking water actually comes from
Almost none of it comes from a river. In the U.S. Geological Survey's 2015 statewide water-use accounting, published in 2020, groundwater provided drinking water for 18.324 million people — 92 percent of Florida's population — while fresh surface water provided drinking water for 1.491 million people, or 8 percent. Most of that groundwater is drawn from the Floridan aquifer system, a sequence of Tertiary carbonate rock underlying approximately 100,000 square miles beneath all of Florida and parts of southeastern Georgia, Alabama and South Carolina, ranging from about 100 feet thick at its updip limit to over 3,300 feet. USGS calls it one of the most productive aquifers in the world, and the Upper Floridan alone supplies drinking water for almost 10 million people. Southeast Florida is the exception: its supply is the Biscayne aquifer, an unconfined shallow limestone that USGS describes as highly permeable and shallow everywhere, and therefore readily susceptible to contamination. That geological split, not city policy, is why two Florida cities on the list above can differ so much.
- U.S. Geological Survey — Water withdrawals, uses, and trends in Florida, 2015 (SIR 2019-5147) — retrieved 2026-07-27
- U.S. Geological Survey — Floridan aquifer system — retrieved 2026-07-27
- U.S. Geological Survey — Karst Aquifers: Upper Floridan and Biscayne Aquifers — retrieved 2026-07-27
- U.S. Geological Survey — Ground Water Atlas of the United States, HA 730-G: Biscayne aquifer — retrieved 2026-07-27