The Blue Water Audit


Blue Water Audit

The Floridan Aquifer is the principal source of water for natural and human systems throughout much of Florida. In addition to being Florida’s primary source of drinking water, the Floridan Aquifer feeds over 1,000 springs.

In the early decades of the 1900s, Florida’s population was less than 1 million. As of the 2010 U.S. Census, Florida’s population has grown to over 18 million. The intensive land development that accompanied Florida’s population growth has resulted in documented impacts on the Floridan Aquifer and springs.

Although human activity has a multitude of effects on the aquifer, elevated nitrate-nitrogen levels and reduced spring flows are the most widespread issues. To better understand these two issues, and to help others understand them, the Florida Springs Institute has developed the Blue Water Audit.


The Blue Water Audit uses existing data to estimate human impact on water quality (through nitrogen loading) and water quantity (through groundwater withdrawal) in the Floridan Aquifer.

Groundwater withdrawals are made for residential, agricultural, commercial, and industrial use. Nitrogen inputs at the land surface primarily come from sources like agricultural fertilizer, lawn and turf fertilizer, waste from humans and livestock, and from the atmosphere – called atmospheric deposition.

Using existing data from a variety of sources, the Blue Water Audit has developed nitrogen loading and groundwater withdrawal estimates. These estimates are used to assign Aquifer Footprints – a Floridan Aquifer Nitrogen Footprint (water quality) and a Floridan Aquifer Groundwater Footprint (water quantity).


Blue Water Audit

Project Area

The Blue Water Audit project area includes 56 counties. These counties were identified by the United States Geological Survey (USGS) as counties that make withdrawals from the Floridan Aquifer. The project area spans over 25 million acres. 


Data from the following agencies are used in the Blue Water Audit:

  • Florida Department of Environmental Protection
  • Florida Department of Health
  • Florida Department of Revenue
  • Florida Department of Agriculture and Consumer Services
  • Northwest Florida Water Management District 
  • Suwannee River Water Management District 
  •  St. Johns River Water Management District 
  • Southwest Florida Water Management District 
  • South Florida Water Management District 
  • U.S. Geological Survey
  • U.S. Census
  • National Atmospheric Deposition Program

The Blue Water Audit Interactive Map is now online!

Coming Soon!

Over the coming months, we'll be adding more

Aquifer Footprint Calculator

An Aquifer Footprint Calculator will be added that will allow you to estimate your own personalized Aquifer Footprints.

Footprint Information

Now that the Blue Water Audit Interactive Map has been added to the website, keep your eye out for additional information about our methodology and the different Aquifer Footprint levels and their impact on the aquifer and springs.

More Content

More information will be added about the Floridan Aquifer and springs. Tips and links will be added that can help you get involved and learn to decrease your own Aquifer Footprint.

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