safe drinking water act safe drinking water act the safe drinking water act (sdwa) is the principal federal law in the united states intended to ensure safe drinking water for the public. pursuant to the act, the environmental protection agency (epa) is required to set standards for drinking water quality and oversee all states, localities, and water suppliers that implement the standards. safe drinking water actlong titlean act to amend the public health service act to assure that the public is provided with safe drinking water, and for other purposesnicknamessdwaenacted bythe 93rd united states congresseffectivedecember 16, 1974citationspublic lawpub. l. 93-523statutes at large88 stat. 1660 (1974)codificationtitles amended42u.s.c. sections created42 u.s.c. § 300flegislative historyintroduced in the senate as s. 433 by warren magnuson (d–wa) on january 18, 1973committee consideration by senate commerce, house commercepassed the senate on june 22, 1973 passed the house on november 19, 1974 (296-84 as h.r. 13002) with amendmentsenate agreed to house amendment on november 26, 1974 () with further amendmenthouse agreed to senate amendment on december 3, 1974 ()signed into law by president gerald ford on december 16, 1974major amendmentssafe drinking water act amendments of 1986, safe drinking water act amendments of 1996 america's water infrastructure act of 2018 the sdwa applies to every public water system (pws) in the united states. there are currently over 148,000 public water systems providing water to almost all americans at some time in their lives. the act does not cover private wells (in 2020, 13% of us households were served by private wells). the sdwa does not apply to bottled water. bottled water is regulated by the food and drug administration (fda), under the federal food, drug, and cosmetic act. national primary drinking water regulations chart of regulatory analysis processes under the sdwa the sdwa requires epa to establish national primary drinking water regulations (npdwrs) for contaminants that may cause adverse public health effects. the regulations include both mandatory requirements (maximum contaminant levels, or mcls; and treatment techniques) and nonenforceable health goals (maximum contaminant level goals, or mclgs) for each included contaminant. as of 2019 epa has issued 88 standards for microorganisms, chemicals and radionuclides. mcls have additional significance because they can be used under the superfund law as "applicable or relevant and appropriate requirements" in cleanups of contaminated sites on the national priorities list. for some contaminants, epa establishes a treatment technique (tt) instead of an mcl. tts are enforceable procedures that drinking water systems must follow in treating their water for a contaminant. federal drinking water standards are organized into six groups: microorganisms disinfectants disinfection byproducts inorganic chemicals organic chemicals radionuclides. microorganisms epa has issued standards for cryptosporidium, giardia lamblia, legionella, coliform bacteria and enteric viruses. epa also requires two microorganism-related tests to indicate water quality: plate count and turbidity. the agency issued its initial surface water treatment rule in 1989, to address contamination from viruses, bacteria and giardia lamblia. the most recent amendment is the long term 2 enhanced surface water treatment rule, promulgated in 2006, requiring public water systems to employ a treatment technique to control cryptosporidium and other pathogens. disinfectants epa has issued standards for chlorine, monochloramine and chlorine dioxide. disinfection by-products epa has issued standards for bromate, chlorite, haloacetic acids and trihalomethanes. inorganic chemicals epa has issued standards for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, copper, cyanide, fluoride, lead, mercury, nitrate, nitrite, selenium and thallium. "lead free" plumbing requirements epa illustration of lead sources in residential buildings the 1986 amendments require epa to set standards limiting the concentration of lead in public water systems, and defines "lead free" pipes as: (1) solders and flux containing not more than 0.2 percent lead; (2) pipes and pipe fittings containing not more than 8.0 percent lead; and (3) plumbing fittings and fixtures as defined in industry-developed voluntary standards (issued no later than august 6, 1997), or standards developed by epa in lieu of voluntary standards. epa issued an initial lead and copper regulation in 1991. the regulation specifies a treatment technique rather than an mcl. congress tightened the definition of "lead free" plumbing in a 2011 amendment to the act. epa published a final rule implementing the amendment on september 1, 2020. in response to the flint, michigan water crisis, epa published revisions to the lead and copper rule on january 15, 2021 addressing testing, pipe replacement and related issues. the rule mandates additional requirements for sampling tap water, corrosion control, public outreach and testing water in schools. the rule continues the requirement for replacement of lead service lines when the "action level" for lead is exceeded, but requires that a utility replace at least 3 percent of its lines annually, compared to 7 percent under the prior regulation. several citizen and environmental groups immediately filed lawsuits challenging the rule. on march 12, 2021 epa delayed the effective date of the rule to june 17, 2021. organic chemicals epa has issued standards for 53 organic compounds, including benzene, dioxin (2,3,7,8-tcdd), pcbs, styrene, toluene, vinyl chloride and several pesticides. radionuclides epa has issued standards for alpha particles, beta particles and photon emitters, radium and uranium. epa proposed regulations for radon in 1991 and 1999. secondary standards secondary drinking water standards are non-regulatory guidelines for aesthetic characteristics, including taste, color, and odor. health advisories epa issues "health advisories" for some contaminants; some of which have not been regulated with mcls. health advisories provide technical information to public health officials about health effects, methods for chemical analysis, and treatment methods. the advisories are not enforceable. epa was given explicit authority to issue advisories in the 1996 sdwa amendments. as of 2022, health advisories have been issued for the following contaminants. epa drinking water health advisories chemical contaminants microbial contaminants boron cyanotoxins dacthal (dcpa) and dacthal degradates cryptosporidium 2,4- and 2,6- dinitrotoluene (dnt) legionella fluoride giardia genx mycobacteria manganese methyl tert-butyl ether (mtbe) oxamyl perchlorate perfluorooctanoic acid (pfoa) and perfluorooctane sulfonate (pfos) perfluorobutanesulfonic acid (pfbs) sodium sulfate 1,1,2,2-tetrachloroethane state standards the sdwa allows states to set standards which are more stringent than the federal standards, and to issue standards for contaminants that epa has not regulated. several states have issued their own standards for a few contaminants, including fluoride, perchlorate and perfluorinated alkylated substances (pfas). future standards unregulated contaminants the sdwa requires epa to identify and list unregulated contaminants which may require regulation. the agency must publish this list, called the contaminant candidate list (ccl) every five years. epa is required to decide whether to regulate at least five or more listed contaminants. epa uses this list to prioritize research and data collection efforts, which support the regulatory determination process. as of 2022, epa has developed five ccls: ccl1: 50 chemical and 10 microbiological contaminants/contaminant groups were listed in 1998. in 2003 epa made a determination that no regulatory action was needed on nine of these contaminants. ccl2: epa carried forward the remaining 51 contaminants from ccl1 for consideration in 2005. in 2008 epa determined that no regulatory action was needed on 11 of these contaminants. ccl3: epa revised its listing process, based on recommendations from the national research council and the national drinking water advisory council (a federal advisory committee). it expanded its initial review to 7,500 potential chemical and microbial contaminants, and subsequently narrowed this universe to a list of 600 for further evaluation. 104 chemicals or chemical groups and 12 microbiological contaminants were listed in 2009. in 2011 epa announced it would develop regulations for perchlorate, which had been listed beginning with ccl1. in 2016 epa determined that no regulatory action was needed on four other listed contaminants, and delayed determination on a fifth contaminant, in order to review additional data. ccl4: epa carried forward the ccl3 contaminants for which determinations had not been made, and requested public comment on additional contaminants. 97 chemicals or chemical groups and 12 microbial contaminants were listed in 2016. in march 2021 epa announced that it would develop regulations for two of the ccl4 contaminants: pfoa and pfos. in november 2022 epa published ccl5. the list includes 66 chemicals, three chemical groups (including pfas) and 12 microbes. on december 27, 2021 epa published a regulation requiring drinking water utilities to conduct monitoring for 29 pfas compounds and lithium. the data are to be collected during 2023 to 2025. epa will pay for the monitoring costs for small drinking water systems (those serving a population of 10,000 or fewer). the agency may use the monitoring data to develop additional regulations. perchlorate the natural resources defense council (nrdc) filed a lawsuit in 2016 to accelerate epa's regulatory process on perchlorate. following a consent decree issued by a federal district court in new york, epa published a proposed rule on june 26, 2019, with a proposed mcl of 0.056 mg/l. on june 18, 2020 epa announced that it was withdrawing its 2019 proposal and its 2011 regulatory determination, stating that it had taken "proactive steps" with state and local governments to address perchlorate contamination. in september 2020 nrdc filed suit against epa for its failure to regulate perchlorate, and stated that 26 million people may be affected by perchlorate in their drinking water. perfluorinated alkylated substances in march 2020 epa announced its proposed regulatory determinations for two pfas in drinking water. in a federal register notice published as a follow-up to ccl4, the agency requested public comment on regulating perfluorooctanoic acid (pfoa) and perfluorooctanesulfonic acid (pfos). in march 2021 epa announced that it would develop regulations for pfoa and pfos. non-community water systems future npdwr standards will apply to non-transient non-community water systems (for example, some schools, factories, office buildings, and hospitals that operate their own water systems) because of concern for the long-term exposure of a stable population. it is important to note that epa's decision to apply future npdwrs to non-transient non-community water systems may have a significant impact on department of energy facilities that operate their own drinking water systems. monitoring, compliance and enforcement epa graphic explaining consumer confidence reports public water systems are required to regularly monitor their water for contaminants. water samples must be analyzed using epa-approved testing methods, by laboratories that are certified by epa or a state agency. a pws must notify its customers when it violates drinking water regulations or is providing drinking water that may pose a health risk. such notifications are provided either immediately, as soon as possible (but within 30 days of the violation) or annually, depending on the health risk associated with the violation. community water systems—those systems that serve the same people throughout the year—must provide an annual "consumer confidence report" to customers. the report identifies contaminants, if any, in the drinking water and explains the potential health impacts. the public water system supervision program comprises "primacy" agencies, which are either state government agencies, indian tribes, or epa regional offices. all state and territories, except wyoming and the district of columbia, have received primacy approval from epa, to supervise the pws in their respective jurisdictions. a pws is required to submit periodic monitoring reports to its primacy agency. violations of sdwa requirements are enforced initially through a primacy agency's notification to the pws, and if necessary following up with formal orders and fines. protection of underground sources of drinking water an underground source of drinking water (usdw) means an aquifer with sufficient quality and quantity of ground water to supply a public water system now or in the future. underground injection control (uic) program the sdwa prohibits any underground injection which endangers drinking water sources. the ninth circuit united states court of appeals while enforcing this prohibition of "harmful injections into drinking water aquifers" explains that underground injection of even clean water can result in the illegal movement of a fluid containing a contaminant into an usdw: the sdwa and its implementing regulations are not concerned with whether an injected fluid is itself contaminated. rather, they are concerned with the result of "injection activity." a permit applicant must show that the proposed activity will not allow "the movement of fluid containing contaminant." id. injections of clean water into the ground can cause the movement of contaminants into an aquifer. for example, contaminants may dissolve into clean water as the injected water passes through the soil on its way to an aquifer.: 1077 underground fluid injection can have disastrous consequences