Safe Drinking Water Act (SDWA)
The Safe Drinking Water Act (SDWA) is a pivotal U.S. federal law enacted on December 16, 1974, aimed at ensuring the safety of public drinking water supplies. It mandates the Environmental Protection Agency (EPA) to establish standards for acceptable levels of various contaminants in over 170,000 public water systems across the country. These standards include limits on microorganisms, disinfection by-products, inorganic and organic chemicals, and radioactive substances. Each state is responsible for enforcing these federal standards, and public water suppliers must regularly monitor and report water quality.
Initially, the EPA identified 25 contaminants, but this list has grown significantly over time. The act also includes provisions addressing municipal water system issues, such as local enforcement shortcomings and the potential health risks posed by contaminated water. Amendments to the SDWA in 1986 and subsequent years have aimed to strengthen protections, including the prohibition of lead in plumbing and oversight of underground injections that could threaten groundwater. However, certain amendments, like those in the Energy Policy Act of 2005, have sparked debate by exempting certain practices, such as hydraulic fracturing, from federal regulation under the SDWA. Overall, the SDWA represents a crucial framework for safeguarding public health through the regulation of drinking water quality in the United States.
Subject Terms
Safe Drinking Water Act (SDWA)
THE LAW: US federal law concerning standards for safe public drinking water
DATE: Enacted on December 16, 1974
The Safe Drinking Water Act was the first law passed in the United States to set standards regarding acceptable levels of certain pollutants in the more than 170,000 public drinking-water supplies across the nation.
Under the Safe Drinking Water Act of 1974, the US Environmental Protection Agency (EPA) is required to set standards regarding the maximum amounts of certain materials allowed in public drinking water; these include harmful inorganic and substances, radioactive substances, microorganisms, and suspended materials. The act requires the individual US states to enforce the EPA’s standards, and it requires each public drinking-water supplier to monitor the quality of its water sent to home users. Initially the EPA included twenty-five materials on its list of contaminants, but over time it has added many others.
Drinking-Water Contaminants
The EPA sets maximum levels of contaminants in public drinking water for microorganisms (such as viruses, colliform bacteria, Giardia, and Cryptosporidium), disinfection by-products (such as bromate and chlorite), disinfectants (such as chloramines and chlorine), inorganic chemicals (such as arsenic, asbestos, chromium, cyanide, fluoride, lead, mercury, and nitrate), organic chemicals (such as atrazine, benzene, dichlorobenzene, and dioxin), and radionuclides. In addition to setting the maximum allowable amount of each contaminant (the maximum contaminant level, or MCL) in drinking water (usually in milligrams of contaminant per liter of water), the EPA states the ideal goal level of the contaminant (usually also in milligrams per liter). The EPA also provides information on the typical sources of the contaminants listed and their possible harmful health effects on humans.
Nitrate, for example, is a common pollutant in natural waters that may come from sewage, animal waste, fertilizer runoff, or the erosion of natural deposits. Nitrate levels thus can become high in groundwater near feedlots for cattle or in areas where large amounts of fertilizers are used, such as agricultural areas. Nitrogen compounds formed from nitrate may bond with hemoglobin in the blood of humans so that less oxygen can be transported through the body by hemoglobin. Humans, especially babies, can become seriously ill from drinking nitrate-polluted waters. The EPA sets the MCL for nitrate (measured as nitrogen) in public drinking water at 10 milligrams per liter.
Harmful microorganisms in water often come from human and animal fecal material. They can produce diarrhea, vomiting, and cramps. Harmful organic materials found in water supplies often come from chemical plants, herbicides, sewage, or insecticides. These can have a variety of negative health impacts, including increased risk of cancer, liver and kidney damage, anemia, reproductive problems, and nervous system problems. Harmful radioactive materials, such as uranium or radium, may enter water supplies from natural materials or as the result of improper disposal of radioactive wastes. Humans and animals exposed to such materials may have increased risk of cancer.
Municipal Water System Problems
Individual US states have often failed in their enforcement of the EPA drinking-water standards. In 1985, for example, more than eighteen hundred cases were reported in which water in public supplies contained contaminants at levels higher than the maximum allowed. The most common problems involved levels of microorganisms, nitrate, and fluoride that exceeded EPA-required levels.
Because of such problems, amendments to the Safe Drinking Water Act were passed by Congress in 1986. This legislation gave the EPA deadlines by which it was to set and enforce reasonable standards for more than eighty potentially dangerous contaminants in public water systems. In setting the MCLs, the EPA was required to take into consideration not only the danger of the contaminants but also the costs of meeting these standards in public waters. Also included in this law was a ban on the use of lead solder and pipes in public water systems. In addition, the 1986 amendments required the EPA to monitor materials injected under the ground, such as oil field brines, to ensure that the injected materials do not contaminate groundwater supplies. The Energy Policy Act of 2005 contained a provision that amended the Safe Drinking Water Act by providing an exemption for "the underground injection of fluids or propping agents (other than diesel fuels) pursuant to hydraulic fracturing operations"; this alteration of the Safe Drinking Water Act has drawn significant criticism for exempting contaminants introduced by hydraulic fracturing ("fracking") operations from federal regulations under the Safe Drinking Water Act.
Bibliography
Cech, Thomas V. “Water Quality.” Principles of Water Resources: History, Development, Management, and Policy. 3rd ed. New York: Wiley, 2010.
Dorsheimer, Wesley T. “Removing Nitrate from Groundwater.” Water Engineering and Management 144.12 (1997): 20–24.
Gray, N. F. Drinking Water Quality: Problems and Solutions. 2nd ed. New York: Cambridge University Press, 2008.
Ketcham-Colwill, J. “Safe Drinking Water Law Toughened.” Environment 28.7 (1986): 42–43.
"Regulations." Center for Disease Control, 10 Aug. 2022, www.cdc.gov/healthywater/drinking/public/regulations.html. Accessed 23 July 2024.
Royte, Elizabeth. Bottlemania: Big Business, Local Springs, and the Battle over America’s Drinking Water. New York: Bloomsbury, 2009.
"Summary of the Safe Drinking Water Act." United States Environmental Protection Agency, 2024, www.epa.gov/laws-regulations/summary-safe-drinking-water-act. Accessed 23 July 2024.