Water Quality

Elizabeth Moreau andGretchen L. Lescord

Lakes are diverse and come in all shapes and sizes. The Trophic State Classification System allows people to group waterbodies into one of four categories, called “trophic states,” based on their level of biological productivity. Knowing what these terms mean can help you understand how your waterbody compares to others, and what changes in its water quality over time could mean. This publication explains how water chemistry is used to determine a waterbody’s trophic state; what criteria are used to define the four trophic states; which trophic state category your waterbody fits into; and how the Trophic State Classification System can be useful.

Heather Donnelly, Ashley Smyth, Shirley Baker, Laura K. Reynolds, andAngela B. Collins

Nitrogen is natural and necessary, yet nitrogen levels above natural levels can cause algal blooms and eutrophication of coastal systems. The purpose of this document is to describe how oysters and oyster reefs remove nitrogen. This new 7-page publication of the UF/IFAS Department of Soil, Water, and Ecosystem Sciences is intended for policymakers, environmental organizations, and coastal residents who want to know about oysters' role in improving water quality through nitrogen removal. Written by Heather Donnelly, Ashley Smyth, Shirley Baker, Laura Reynolds, and Angela Collins.

Jay Capasso, Lisa Krimsky, andJehangir H. Bhadha

A UF/IFAS numbered peer reviewed Fact Sheet. in support of UF/IFAS Extension program: ==Water==

Gabriela Sullivan and Martha Monroe

Residents, farmers, and businesses in southwestern Georgia and northern and central Florida depend on the groundwater from the Floridan Aquifer. The availability of this clean water is important for natural ecosystems, agriculture, the economy, tourists, and the people who call Florida and Georgia home. This fact sheet will provide an overview of the Floridan Aquifer and how water from the Floridan Aquifer cycles through natural and human systems.

Kimberly Moore, Mica McMillan, and Lorna Bravo

Rain barrels are a great way to conserve water, save money, and contribute to a sustainable landscape. However, adoption of rain barrels is low with homeowners concerned about water quality especially from different roof types. Our analysis of nutrients showed that there was no difference in nutrient levels based on roof type. All water samples had low levels of nutrients and no detectable pathogens. Based on our analysis, the water collected from these rain barrels would be safe to use for non-potable uses in the landscape and garden.

Anthony Halcyon, Mary G. Lusk, and Ann C. Wilkie

This publication explains what happens when stormwater runoff enters constructed environments, its impacts on water bodies, and how individuals can take steps to lower their own stormwater runoff footprint. This guide can increase awareness of ways to reduce each person's role in water quality impairment by stormwater pollution. This publication is intended primarily for urban residential readers and does not focus on agricultural runoff. 

Alexander J. Reisinger, Michael D. Dukes, Basil V. Iannone III, J. Bryan Unruh, and Samuel J. Smidt

Originating from environmental or humans sources, too much nitrogen (N) and/or phosphorus (P) in water bodies can degrade water quality. In an attempt to reduce the contribution of human sources of N and P to local waters, urban fertilizer ordinances have been adopted in at least 35 counties in Florida and 97 additional Florida municipalities. Despite this work, the efficacy of fertilizer ordinances are debated by end users. The purpose of this publication is to summarize a peer-reviewed, scientific article that investigated impacts of fertilizer on long-term water quality trends in Florida lakes (Smidt et al. 2022) and is intended to be used by UF/IFAS Extension faculty and/or regulatory officials considering adopting or modifying an urban fertilizer ordinance. We encourage green industry professionals and concerned community members to share the effectiveness of fertilizer ordinances.

Mary G. Lusk andTanya Charan

The Up in the Air, Down in the Water program is a combined research and education effort of the Urban Water Cycle Lab at the UF/IFAS Gulf Coast Research and Education Center in Hillsborough County, Florida. The purpose of this fact sheet is to explain where the nitrogen (N) in atmospheric deposition comes from, how it moves to Earth’s surface, how it can affect water quality, and how we can better manage atmospherically derived N in our watersheds. Written by Mary G. Lusk and Tanya Charan, and published by the UF/IFAS Department of Soil, Water, and Ecosystem Sciences, October 2025.

Alexander J. Reisinger, Andrea Albertin, Eban Bean, Ashley Smyth, andP. Christopher Wilson

Water quality is a broad term used to describe a range of physical, chemical, and/or biological characteristics of water. Many different factors contribute to water quality. The decision of whether the quality of a given water body is good or bad, whether it is acceptable or unacceptable, varies from place to place and depends on the intended use of that water body. In Florida, water quality criteria have been established for six different types of water bodies, and these criteria vary by the use of each water body type. This publication defines general terminology and approaches used to describe water quality. It is targeted towards individuals who have an interest in water quality issues but may not have training in the specific details of these issues. Ultimately, this publication will allow the reader to have a deeper understanding of specific water quality issues and regulations.

Natalia A. Cooper andMartha C. Monroe

We rely on clean water to sustain human life, ecosystems, and food supply. In Florida and southwest Georgia, the Floridan Aquifer supplies much of the water we use. As populations grow and regional economies expand, the impacts of human activity on water pollution become more widespread. We must take preventative actions to minimize water pollution to maintain the quality of our water sources, and thus, our quality of life.