for drinking water and, in turn, for human health. injected fluid is hard to trace once it enters the ground, and polluted aquifers are hard to remediate. congress' cautious "preventive" approach requires permit applicants to show that their injections will not harm underground sources of drinking water. it presumes, until an applicant shows otherwise, that injections will contaminate an usdw. although this approach may result in forbidding some injections that would not contaminate an usdw, it is a valid exercise of congress' authority.: 1080 epa poster illustrating uic well classes the 1974 sdwa authorized epa to regulate injection wells in order to protect underground sources of drinking water. the uic permit system is organized into six classes of wells. class i. industrial waste (hazardous and non-hazardous) and municipal wastewater disposal wells class ii. oil and gas related injection wells (except wells solely used for production; see hydraulic fracturing exemption) class iii. solution mining wells class iv. shallow hazardous and radioactive waste injection wells (no longer permitted) class v. wells that inject non-hazardous fluids into or above underground sources of drinking water class vi. geologic sequestration wells for carbon dioxide. epa has granted uic primacy enforcement authority to 34 states for class i, ii, iii, iv and v wells. seven additional states and two tribes have been granted primacy authority for class ii wells only. epa manages enforcement of class vi wells directly. if a state does not take appropriate enforcement action then epa must issue an order requiring a violator to comply with the requirements, or the agency will initiate a civil enforcement action. the sdwa directly provides for citizen civil actions. hydraulic fracturing exemption congress amended the sdwa in 2005 to exclude hydraulic fracturing, an industrial process for recovering oil and natural gas, from coverage under the uic program, except where diesel fuels are used. this exclusion has been called the "halliburton loophole". halliburton is the world's largest provider of hydraulic fracturing services. the measure was a response to a recommendation from the energy task force, chaired by vice president dick cheney in 2001. (cheney had been chairman and ceo of halliburton from 1995 to 2000.) wellhead protection areas the act requires states to establish wellhead protection programs to protect underground sources of drinking water. wellhead protection programs must specify the duties of agencies, determine the wellhead protection areas, identify sources of contaminants, implement control measures to protect the wellhead protection areas, and a contingency plan for alternative drinking water supplies in the event of contamination. federal agencies having jurisdiction over potential sources of contaminants must comply with all requirements of the state wellhead protection program. emergency power the "updated guidance on invoking emergency authority under section 1431 of the safe drinking water act" shows that 42 u.s.c. § 300i gives the epa administrator broad power to protect public water systems and underground sources of drinking water (usdws).: 3 this guidance encourages more widespread use of the epa's emergency powers.: 3 this emergency power is granted when the administrator receives "information that a contaminant which is present in or likely to enter a public water system or an underground source of drinking water ... which may present an imminent and substantial endangerment to the health of persons" and that appropriate agencies have not acted.: 6–7 since this emergency power protection applies to all usdws it includes potential future supplies of public water and even private wells.: 7–8 the imminent endangerment includes contaminants that lead to chronic health effects that may not be realized for years such as lead and carcinogens.: 9–10 to prevent harm from occurring the epa administrator may issue administrative orders or commence civil actions even without absolute proof.: 11 judicial review and civil actions whenever epa finds a violation of the uic program and the state does not or cannot act, the agency must issue an administrative order or to file a civil action to require compliance. a citizen can file a petition for judicial review of epa final actions. a citizen may also file against any violator of the sdwa or against epa for failure to take action under the sdwa which is not discretionary. epa emergency administrative orders are also final actions subject to judicial review. related programs airline water supplies in 2004, epa tested drinking water quality on commercial aircraft and found that 15 percent of tested aircraft water systems tested positive for total coliform bacteria. epa published a final regulation for aircraft public water systems in 2009. the regulation requires air carriers operating in the u.s. to conduct coliform sampling, management practices, corrective action, public notification, operator training, and reporting and recordkeeping. an airline with a non-complying aircraft must restrict public access to the on-board water system for a specified period. source water assessment the sdwa requires each state to delineate the boundaries of areas that public water systems use for their sources of drinking water—both surface and underground sources. within each source area the origins of regulated contaminants are identified in order to determine the susceptibility of the public water systems. this information can help communities understand the risks to their sources of drinking water. whistleblower protection the sdwa includes a whistleblower protection provision. employees in the us who believe they were fired or suffered another adverse action related to enforcement of this law have 30 days to file a written complaint with the occupational safety and health administration. history prelude prior to the sdwa there were few national enforceable requirements for drinking water. in 1914 the u.s. public health service (phs) published a set of drinking water standards, pursuant to existing federal authority to regulate interstate commerce, and in response to the 1893 interstate quarantine act. as such the standards were directly applicable only to interstate common carriers such as railroads. for local drinking water utilities, these standards were basically recommendations and not enforceable requirements. however, many municipal utlities began to voluntarily adopt the standards. improvements in chemical testing methods in the 1970s, particularly for synthetic organic chemicals, allowed for the detection of smaller concentrations of contaminants. here is a picture of mary workman she is holding a jar of undrinkable water that comes from her well, and has filed a damage suit against the hanna coal company, steubenville (jefferson county, ohio), 1973. under state programs, some water works managers mistakenly believed that the major, real threats were behind them and their primary focus was on providing consistent and effective service through aging infrastructure, with major efforts at maintaining the bacteriological quality of drinking water. 1974 act the safe drinking water act was one of several pieces of environmental legislation in the 1970s. discovery of contamination from organic chemicals in public water systems and the lack of enforceable, national standards persuaded congress to take action. the 1974 law very clearly defined roles and responsibilities, giving epa the job of generating scientifically based standards that would be applicable to all water supplies that served 25 or more customers and creating a process for setting new standards. epa was mandated to contract with the national academy of sciences (nas) for a major study of contaminants in drinking water that might have health significance and to issue revised regulations once the nas report was completed. 1986 amendments the 1986 sdwa amendments required epa to apply future npdwrs to both community and non-transient non-community water systems when it evaluated and revised current regulations. the first case in which this was applied was the "phase i" final rule, published on july 8, 1987. at that time npdwrs were promulgated for certain synthetic volatile organic compounds and applied to non-transient non-community water systems as well as community water systems. this rulemaking also clarified that non-transient non-community water systems were not subject to mcls that were promulgated before july 8, 1987. the 1986 amendments were signed into law by president ronald reagan on june 19, 1986. in addition to requiring more contaminants to be regulated, the 1986 amendments included: wellhead protection new monitoring for certain substances filtration for certain surface water systems disinfection for certain groundwater systems restriction on lead in solder and plumbing more enforcement powers. 1996 sdwa amendments president bill clinton signs the safe drinking water amendments act of 1996 in the east room in 1996, congress amended the safe drinking water act to emphasize sound science and risk-based standard setting, small water supply system flexibility and technical assistance, community-empowered source water assessment and protection, public right-to-know, and water system infrastructure assistance through a multibillion-dollar state revolving loan fund. the amendments were signed into law by president bill clinton on august 6, 1996. main points of the 1996 amendments consumer confidence reports. all community water systems must prepare and distribute annual reports about the water they provide, including information on detected contaminants, possible health effects, and the water source(s) for the system. cost-benefit analysis. epa must conduct a thorough cost-benefit analysis for every new standard to determine whether the benefits of a drinking water standard justify the costs. drinking water state revolving fund. states can use this fund to help water systems make infrastructure or management improvements or to help systems assess and protect their source water. microbial contaminants and disinfection byproducts. epa is required to strengthen protection for microbial contaminants, including cryptosporidium, while strengthening control over the byproducts of chemical disinfection. epa promulgated the stage 1 disinfectants and disinfection byproducts rule and the interim enhanced surface water treatment rule to address these risks. operator certification. water system operators must be certified to ensure that systems are operated safely. epa issued guidelines in 1999 specifying minimum standards for the certification and recertification of the operators of community and non-transient, noncommunity water systems. these guidelines apply to state operator certification programs. all states are currently implementing epa-approved operator certification programs. public information and consultation. the sdwa emphasizes that consumers have a right to know what is in their drinking water, where it comes from, how it is treated, and how to help protect it. epa distributes public information materials on its website and holds public meetings, working with states, tribes, local water systems, and environmental and civic groups, to encourage public involvement. small water systems. small water systems are given special consideration and resources under sdwa, to make sure they have the managerial, financial, and technical ability to comply with drinking water standards. 2005 amendment through the energy policy act of 2005, the safe drinking water act was amended to exclude the underground injection of any fluids or propping agents other than diesel fuels used in hydraulic fracturing operations from being considered as "underground injections" for the purposes of the law. 2011 amendment congress passed the reduction of lead in drinking water act in 2011. this amendment, effective in 2014, tightened the definition of "lead-free" plumbing fixtures and fittings. 2015 amendments the drinking water protection act was enacted on august 7, 2015. it required epa to submit to congress a strategic plan for assessing and managing risks associated with algal toxins in drinking water provided by public water systems. epa submitted the plan to congress in november 2015. the grassroots rural and small community water systems assistance act was signed by president barack obama on december 11, 2015. the amendment provides technical assistance to small public water systems, to help them comply with national primary drinking water regulations. 2016 amendments the water infrastructure improvements for the nation act added several provisions to the sdwa, along with providing financial assistance to the city of flint, michigan in responding to its lead contamination crisis, as well as assistance for other communities. the provisions include: expanding the water infrastructure public-private partnership loan program requiring public notification when household drinking water contains lead levels above the epa action level (currently 0.015 mg/l) establishing a voluntary program for testing for lead in drinking water at schools and childcare centers creating a public information clearinghouse on alternative drinking water delivery systems. 2018 amendments america's water infrastructure act of 2018 environmental justice an above ground water tank on the white mountain apache tribe in arizona, the epa worked collaboratively with the goal of improving access to safe drinking water on tribal lands. the sdwa can promote environmental justice by increasing the safety of drinking water in the communities most adversely impacted by water contamination. communities of color and low-income communities are