text: Drinking Water & Human Health in Florida\n\nGroundwater is the source of drinking water for 90% of Florida residents. Public water supply use has increased 134% since 1970. Data from over 1,900 wells in Florida's ambient monitoring network indicate generally good water quality, but local groundwater contamination problems exist. Agricultural chemicals, including aldicarb, alachlor, bromacil, simazine, and ethylene dibromide (EDB) have caused local and regional (in the case of EDB) problems. Other threats include petroleum products from leaking underground storage tanks, nitrates from dairy and other livestock operations, fertilizers and pesticides in stormwater runoff, and toxic chemicals in leachate from hazardous waste sites. The state requires periodic testing of all community water systems for 118 toxic organic chemicals.\n\nPotential sources of groundwater contamination are numerous in Florida. The state's unique hydrogeologic features of a thin soil layer, high water table, porous limestone and large quantities of rainfall coupled with rapid population growth, result in a groundwater resource extremely vulnerable to contamination. There are tens of thousands of potential point sources such as surface-water impoundments, drainage wells, underground storage tanks, flowing saline water wells, hazardous wastes sites, power plants, landfills and cattle and dairy feedlots. Similarly there are numerous septic tanks and urban and industrial areas that may discharge water with undesirable quality. Non-point sources that have vast potential for groundwater contamination include coastal saltwater bodies, agricultural and horticultural practices, and mining. Wetlands (10.9 million acres (4.4 Mha)) provide buffers between anthropogenic activities and water quality of lakes, streams, and groundwater. Recognition of the function of wetlands is essential for sustainable development in Florida.\nConditions in Your Watershed\n\nThe Environmental Protection Agency provides information on drinking water systems by county. The Florida Department of Environmental Protection (FDEP) Drinking Water Section lists drinking water violations in Florida and the FDEP Source Water Program manages state surface waters.\n\nFlorida Aquifers Data on organic quality of water from the state's principal aquifers are limited; nevertheless, occasional incidences of organic contaminants that may affect human health and welfare are a reality. In the Northwest Florida Water Management District the most prevalent organic contaminants are dry-cleaning solvents and leaking underground gasoline storage tanks. Santa Rosa, Escambia and Holmes counties in the Florida panhandle get their water from the sand and gravel aquifer. This is the sole source for Escambia County. Wells furnishing water for the county populati on are from two to five hundred feet deep. Ten major wells owned by the Escambia County Utility Authority (ECUA) are contaminated. A dry-cleaning solvent (PCE) is the biggest contaminant. Benzene, which indicates petroleum contamination, has also been identified in multiple wells. It is important to point out that rainfall within the boundaries of the county accounts for nearly all the available groundwater. Because of groundwater recharge characteristics, any disposal of waste products or misuse of toxic chemicals on the land surface, whether accidental or intentional, has a high probability for adversely impacting groundwater.\n\nThe Biscayne aquifer has been designated by the USEPA as a "sole source" drinking-water supply. The Biscayne aquifer is managed closely to control saltwater intrusion. Water in the aquifer is primarily a calcium bicarbonate type that does not exceed standards for most uses. However, it is subject to contamination by organic solvents used in industry, pesticides and nutrients used in agricultural and urban settings, and leaking fuel storage facilities. Iron concentration in untreated groundwater is commonly lar