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Evolution of Water Quality Regulations in the United States and Florida1

Kati W. Migliaccio, Yuncong Li, and Thomas A. Obreza 2


Figure 2. 
Figure 2. 
Credit: ShaneGross/iStock/Thinkstock, © ShaneGross



Water is essential to sustain life. However, not only do we all need a certain quantity of water each day, but the quality of the available water is also critical. Water quality protection in the United States evolved during the 20th century, from initially ensuring navigability of waterways to the present emphasis on protecting our natural ecosystems.

The intent of this document is to summarize US water quality legislative history, Florida water quality legislation (particularly regarding Total Maximum Daily Loads), and water quality criteria. This document provides a background for understanding water quality and how it is evaluated and regulated in the US with particular focus on the state of Florida.

US Water Quality Legislative History

Interest in protecting US waters through legislation started at the beginning of the 20th century with the Rivers and Harbors Act (RHA) of 1899. The RHA included a provision (known as the Refuse Act) that addressed the dumping of refuse into waterways (Downing et al. 2003). Although the RHA with the Refuse Act included many environmental policies, few were actively enforced.

The next significant water-related legislation was the 1948 Federal Water Pollution Control Act. This act placed responsibility for controlling water pollution on the states and primarily focused on the treatment of sewage wastes (Deason et al. 2001). Thus, early water protection efforts focused on "point sources" of pollution. (Point source pollution refers to pollution from a stationary location or fixed facility, such as a pipe, ditch, ship, or factory smokestack.)

Water quality began to receive more attention in the late 1960s due to the 1969 Cuyahoga River fire in Cleveland, Ohio, and growing public awareness of water quality decline due, in part, to Rachel Carson's book—Silent Spring (Carson 1962). Thus, it is not surprising that amendments to the Federal Water Pollution Control Act were passed in the 1970s to improve the protection of US water resources. These amendments are commonly referred to as the 1972 Clean Water Act (CWA). The CWA identified the goal of restoring waters considering their chemical, physical, and biological integrity. The CWA also set federal requirements for identifying polluted or impaired water bodies and for developing estimated loads of a particular pollutant that could be received by each water body and still meet water quality standards. This concept is often referred to as the Total Maximum Daily Load (TMDL). Additionally, the CWA gave authority to the US Environmental Protection Agency (EPA) to issue permits to major pollutant dischargers and to establish national discharge limitations.

Although the CWA included many water quality measures, few were actively enforced. This lack of action led to an era of lawsuits during the 1990s when more than 35 states and environmental groups sued the EPA, alleging that it failed to fully implement requirements set forth by the CWA, such as the TMDL (Copeland 2005). Hence, additional legislation and clarification of the TMDL requirements in the CWA were developed.

Currently, the TMDL program is administered considering the 1992 TMDL regulations. Specifically (per EPA website information), states, territories, and authorized tribes must:

  • submit a list of waters that are impaired and/or threatened by pollutants (often referred to as the 303(d) list);

  • establish priority ranking of the listed water bodies, taking into account the severity of pollution and the designated uses of the water;

  • identify waters targeted for TMDL development; and

  • develop and implement TMDLs.

The EPA defines a TMDL as "the sum of allocated loads of pollutants set at a level necessary to implement the applicable water quality standards, including: waste load allocations from point sources and load allocations from nonpoint sources and natural background conditions. (Nonpoint sources are sources that are diffuse, or without a single point of origin, such as agriculture, urban, and construction sources.) A TMDL must contain a margin of safety and a consideration of seasonal variations" (US EPA 2007a). The TMDL is sometimes expressed as an equation:


where WLA is the waste load allocation from point sources, LA is the load allocation from nonpoint sources and natural background concentrations, and MOS is the margin of safety. MOS is used to account for uncertainties and variability in estimating WLA and LA. Often, MOS is considered to be a percentage (10 to 15%) of the WLA and LA. Others have considered conservative estimations of WLA and LA and thus described the estimated MOS as implicit due to these conservative assumptions.

The determination of appropriate WLA and LA for a TMDL requires that the allowable load for the particular constituent be known or attainable. Thus, there must be a designated concentration or load that should not be exceeded that ensures that designated uses are being met for constituents.

The states, territories, and authorized tribes were charged with the mission to identify impaired or threatened waters and develop TMDLs as needed.

Florida Water Quality Legislation

Legislation was passed in Florida to address the TMDL mandate that was issued by the EPA, namely the 1999 Florida Watershed Restoration Act (FWRA) (s.403.067 F.S.). More detailed information on the FWRA can be found in Olexa et al. (2005). The FWRA identified methods that the Florida Department of Environmental Protection (FDEP) would use to develop and implement TMDLs.

In accordance with the FWRA, the FDEP designed a TMDL plan that divided the state into five basin groups (Figure 1). For each basin group, five development phases were identified. The five-phase cycle consists of the following: Phase 1—initial basin assessment, Phase 2—coordinated monitoring, Phase 3—data analysis and TMDL development, Phase 4—basin management plan development, and Phase 5—begin implementation of basin management plan. The five-phase cycle rotates through each basin group every 5 years (FDEP 2007).


Figure 1. Five basin groups as identified by Florida Department of Environmental Protection.
Figure 1.  Five basin groups as identified by Florida Department of Environmental Protection.
Credit: Kati Migliaccio, UF/IFAS


FDEP is in the process of rotating among the basin groups and phases. The most current reports for this program can be obtained from the FDEP website:

Water Quality Criteria

US water quality history and regulations have evolved due to new knowledge, public support, and growing water demands. Although these regulations are in place, their appropriate implementation depends on the ability to determine the concentration or load at which a constituent (or measured parameter) becomes a water quality pollutant.

FDEP has been involved in the process of developing water quality nutrient criteria for many years. Florida waters are designated with either numeric or narrative nutrient criteria. Numeric nutrient standards are provided in Florida Administrative Code (FAC) and are available on the FDEP website (; Table 1). Chapter 62-302 F.A.C. is Surface Water Quality Standards and Chapter 62-303, F.A.C. is Identification of Impaired Surface Waters.

Future Direction of Water Quality

As more information is known and public awareness of water quality issues increases, better government programs are being developed and enforced to preserve water resources. Protecting and conserving water supplies is likely to be a dominant issue in the future due to competing water uses (e.g., growing population, energy production, agriculture, etc.) and limited water supplies. Hence, continued research and development of better water conservation practices and policies are critical to sustaining our water quantity and quality to ensure water resources' designated uses.


Carson, R. 1962. Silent Spring. Houghton Mifflin: Boston, MA.

Copeland, C. 2005. Clean Water Act and Total Maximum Daily Loads (TMDLs) of pollutants. CRS Report for Congress. Order Code 97–831 ENR

Deason, J. P., T. M. Schad, and G. W. Sherk. 2001. "Water policy in the United States: a perspective." Water Policy 3:175–192.

Downing, D. M., C. Winer, and L. D. Wood. 2003. "Navigating through clean water act jurisdiction: a legal review." Wetlands 23(3):475–493.

FDEP. 2007. TMDL development cycle.

FDEP. 2013. Implementation of Florida's Numeric Nutrient Standards.

Migliaccio, K. W. and Y. C. Li. 2007. Evolution of Water Quality Regulations in the United States and Florida. ABE 381. Gainesville: University of Florida Institute of Food and Agricultural Sciences.

Olexa, M. T., L. D'Isernia, L. Minton, D. Miller, and S. Corbett. 2005. Handbook of Florida Water Regulations: Florida Watershed Restoration Act. FE608. Gainesville: University of Florida Institute of Food and Agricultural Sciences.

US EPA. 2000a. Ambient water quality criteria recommendations, rivers and streams in nutrient ecoregion IX. Office of Water. EPA 822-B-00-019.

US EPA. 2000b. Ambient water quality criteria recommendations, rivers and streams in nutrient ecoregion XII. Office of Water. EPA 822-B-00-021.

US EPA. 2001. Fact sheet: ecoregional nutrient criteria. Office of Water. EPA-822-F-01-010.

US EPA. 2006. National recommended water quality criteria. Office of Water, Office of Science and Technology 4304T.

US EPA. 2007a. Overview of current Total Maximum Daily Load – TMDL – program and regulations.

US EPA. 2007b. Terms of Environment: Glossary, Abbreviations and Acronyms.


Table 1. 

Numeric nutrient standards in Florida administrative code from the surface water quality standards chapter.


Publication #ABE 381

Date: 10/11/2020


    Fact Sheet

    About this Publication

    This document is ABE 381, one of a series of the Department of Agricultural and Biological Engineering, UF/IFAS Extension. Original publication date December 2007. Revised January 2011, February 2014, and April 2017. Reviewed May 2020. Visit the EDIS website at

    About the Authors

    Kati W. Migliaccio, associate professor, Department of Agricultural and Biological Engineering, UF/IFAS Tropical Research and Education Center; Yuncong Li, professor, Department of Soil and Water Sciences, UF/IFAS Tropical Research and Education Center; and Thomas A. Obreza, senior associate dean for Extension and professor, Department of Soil and Water Sciences; UF/IFAS Extension, Gainesville, FL 32611.


    • Kati Migliaccio