If you live where the aquifer is vulnerable to contamination due to a lack of impervious soils, and you apply fertilizer to your lawn, garden or pasture, you have an elevated nitrogen aquifer footprint. If your home’s wastewater is disposed of in a septic system and your lot is less than five acres, you have an elevated nitrogen footprint. If you water your yard and landscaping plants with groundwater or consume unusually large volumes of water in your house, you also have an elevated water use footprint.

The Howard T. Odum Florida Springs Institute has completed the first phase of the “Blue Water Audit,” an assessment of the aquifer footprint of the 4.2 million Floridians living in the springs region of North and Central Florida. Geographic information system databases were analyzed by overlaying information on land use, aquifer vulnerability, property ownership, method of wastewater disposal, human population and other factors to estimate the effects of humans and their domesticated animals on the quantity and quality of the water in the underlying aquifer.

If you live within an urban boundary, your estimated impact on the aquifer is reported as an average with all your urban neighbors. If you own property covering five or more acres outside of an urban boundary, your aquifer footprint is reported individually for your property. The audit provides the first comprehensive estimate of individual human impacts to the aquifer and the springs and other surface water bodies it supports.

The audit estimates that about 22,000 tons of nitrate-nitrogen reach the aquifer each year in Florida’s 15 million-acre springs region. An estimated 1 billion gallons per day of groundwater is pumped cumulatively by residents, municipalities, farmers and industries in north-central Florida. The average per capita nitrogen load and groundwater use in this springs region is 10.6 pounds per year and 230 gallons per day, respectively.

For Alachua County residents, the per-capita averages are 9.5 pounds per year of nitrogen loading and 142 gallons per day of groundwater use. By contrast, the aquifer footprint for an individual living in Suwannee County (i.e., highly vulnerable aquifer, intensive agriculture and low human population compared to livestock population) is 84.5 pounds per year of nitrogen loading and 1,455 gallons of groundwater per day.

A few counties have lower estimated footprints. For example, Leon County has a per capita nitrogen footprint of 5.1 pounds per year and a groundwater use footprint of 75.8 gallons per day per person. These lower numbers reflect a large urban population within a region of low agricultural productivity.

The aquifer footprint of a farmer irrigating and fertilizing 200 acres of vegetables or a dairyman keeping 2,000 milk cows is more than 100 times more impactful to the aquifer than a person living in an apartment or retirement village. A lush golf course may have an aquifer footprint equivalent to thousands of individuals.

It is imperative for environmentally damaging businesses and local governments to reduce their aquifer footprints. In pursuit of improved human health and environmental protection, the public interest should take precedence over personal gain or extravagant lifestyles.

The net result of the choices we are making in Florida’s springs region is an average groundwater nitrate-nitrogen concentration 2,900 percent higher than natural background concentrations and an overall decline in average spring flows of about 32 percent. One goal of the audit is to continue making these estimates to determine how much the state’s roughly $100 million annual springs protection expenditures are, or are not, improving conditions in the aquifer and springs.

Despite record funding, our springs and drinking water supply are becoming more depleted and polluted every year. Reducing your personal aquifer footprint is essential. But without government action, the springs and aquifer cannot be saved. Keep that in mind when you vote this year.

Robert Knight is director of the Springs Institute.