A few factoids from the 2010 USGS Report on national water use help explain relative magnitudes of Florida water use. This state:

• Withdrew more fresh groundwater than any other state in the East (Table 1)
• Withdrew 791 gallons per capita per day (combined fresh and saline water) (Table 1)
• Withdrew more total freshwater for irrigation that any other Eastern state (Table 2A) (Also was #1 in the East for both surface water irrigation (Table 3A) and groundwater irrigation (Table 4A)
• Relies on groundwater for almost 90% of  public water supply (Table 5).

That seems like a lot of water, enough to put a considerable strain on Florida water resources.