Water pollution in the United States is a growing problem that became critical in the 19th century with the development of mechanized agriculture, mining, and industry, although laws and regulations introduced in the late 20th century have improved water quality in many water bodies. Extensive industrialization and rapid urban growth exacerbated water pollution as a lack of regulation allowed for discharges of sewage, toxic chemicals, nutrients and other pollutants into surface water.
In the early 20th century, communities began to install drinking water treatment systems, but control of the principal pollution sources—domestic sewage, industry, and agriculture—was not effectively addressed in the US until the later 20th century. These pollution sources can affect both groundwater and surface water. Multiple pollution incidents such as the Kingston Fossil Plant coal fly ash slurry spill (2008) and the Deepwater Horizon oil spill (2010) have left lasting impacts on water quality, ecosystems, and public health in the United States. The United States Geological Survey revealed that at least 45% of tap water in the United States contains what are commonly referred to as forever chemicals.
Many solutions to water pollution in the United States can be implemented to curtail water pollution. This includes municipal wastewater treatment, agricultural and industrial wastewater treatment, erosion and sediment control, and the control of urban runoff. The continued implementation of pollution prevention, control and treatment measures are used to pursue the goal of maintaining water quality within levels specified in federal and state regulations. However, many water bodies across the country continue to violate water quality standards in the 21st century.
Overview
Water pollution was identified as a growing problem in the US by scientists, government officials and the public in the 19th century. Many cities and towns piped their untreated domestic sewage into nearby waterways. Wastewater discharged by factories, mines and other businesses increased as the economy expanded. Large cities, and later smaller communities, began to install drinking water treatment systems in the early 20th century, but sewage treatment plants were limited at that time and not very effective. Effective control of sewage and industrial pollution was not comprehensively addressed until later in the century. Agricultural pollution emerged as a growing problem in the 20th century with the increased mechanization of agriculture and increasing use of chemicals.
Following the passage of the 1972 Clean Water Act (CWA), the levels of water pollution in US waterways generally have experienced a dramatic decrease with respect to sewage outflow and many types of industrial wastewater. The 1972 law did not address surface runoff from farms or urban runoff pollution. Municipal stormwater runoff became subject to regulation in 1987, although implementation of the requirements by cities and towns has been a slow and difficult process. About half of U.S. stream and river miles continue to violate federal water quality standards in the 21st century. Surveys of lakes, ponds and reservoirs indicated that about 70 percent were impaired (measured on a surface area basis), and a little more than 70 percent of the nation’s coastlines, and 90 percent of the surveyed ocean and near coastal areas were also impaired. A related 2017 report on the nation's water quality prepared by the U.S. Environmental Protection Agency (EPA) stated that 46% of river and stream miles, 21% of the nation’s lakes, 18% of coastal and Great Lakes waters, and 32% of the nation's wetland areas are in "poor biological condition." Agriculture, industry, urban runoff, and other sources continue to discharge waste into surface waters nationwide. This poses huge environmental and health risks given that these water sources are used as drinking water and for agricultural use.
While the CWA has made positive contributions to the state of surface water in the United States, the law does not fully address all aspects of pollution. Many think that Congress should revise or expand the law to address these problems and gaps in regulation. Although the CWA has been effective in controlling point source pollution (where the discharge is typically via a pipe or ditch and assigning responsibility for mitigation is straightforward), it has not been as effective with nonpoint sources (where discharges are diffuse, and treatment or prevention may be technically difficult or very expensive).
Despite the negative health and ecosystem impacts of water pollution, solutions exist that are able to treat and decrease pollution levels in water bodies.