Drinking Water and Public Health in the United States

  • Date: Nov 05 2019
  • Policy Number: 20195

Key Words: Water, Environmental Health

Abstract

The purpose of this policy statement is to guide further debate and decision making by APHA regarding a public policy on safe drinking water. This statement provides the scientific basis and justification for the importance of improving our nation’s drinking water supplies. It also emphasizes the vital role that public health practitioners and policymakers can play in this important public health issue. In addition, it will enable APHA to become a policy leader with respect to safe drinking water. The objectives of this policy statement are to position APHA to: (1) provide expert guidance to the Environmental Protection Agency and relevant agencies on decision making regarding drinking water standards and regulations; (2) improve public health education about drinking water risks, specifically education for public health and health care professionals; and (3) promote sufficient funding for federal and state drinking water programs.

Relationship to Existing APHA Policy Statements

The following APHA policy statements identify contaminants that pollute or otherwise impact drinking water sources in the United States: 20182 (The Environmental and Occupational Health Impacts of Unconventional Oil and Gas Industry), 20037 (Precautionary Moratorium on New Concentrated Animal Feed Operations), 20104 (A Precautionary Approach to Reducing American Exposure to Endocrine Disrupting Chemicals), and 20126 (Anticipating and Addressing Sources of Pollution to Preserve Coastal Watersheds, Coastal Waters, and Human Health). The policy proposed here summarizes these various sources in addition to the information provided in Policy Statement 200015 (Drinking Water Quality and Public Health) and makes specific recommendations to address public health concerns and policies as a means of ensuring safe drinking water for the U.S. population.

Problem Statement

Safe drinking water is essential to ensure public health and is a human right. In the United States, the quality and safety of our drinking water continues to be an important public health issue. From 2003 to 2009, the Centers for Disease Control and Prevention (CDC) estimated that up to 477,000 people fell ill and approximately 6,900 died from 13 of the most common waterborne infectious diseases in the United States.[1] The U.S. Environmental Protection Agency (EPA) estimates that public drinking water systems are the source of drinking water for 94% of U.S. residents. In 2017, almost 22 million of these individuals drank water from systems that were in violation of public health standards.[2] The CDC reports that, since 2009, the top causes of disease outbreaks related to public water systems have been associated with Campylobacter, Legionella, 4-methylcyclohexanemethanol, Cryptosporidium, Norovirus, cyanotoxins, Escherichia coli, and Giardia.[3] Legionella, which has been on the rise in the United States as an emerging contaminant, was associated with 57% of the 42 drinking water–associated outbreaks and all 13 deaths reported in 2013–2014.[4] More than 13 million households in the United States depend on private well water, which is not monitored under the Safe Drinking Water Act.[2] Drinking water use is shaped by social and cultural beliefs that are further influenced by the diversity of the United States.[5]

Clearly, officially recorded cases of waterborne disease represent only the tip of the iceberg. Most drinking water in the United States is obtained from surface water or groundwater sources, each of which can be contaminated.[6] The surface waters of rivers, streams, lakes, and ponds are under threat from environmental contamination. Water source contamination in the United States most commonly originates from industrial and agricultural sources, human and animal waste, inadequate or damaged treatment and distribution systems, and natural sources such as geological formations, and further effects are attributable to an aging water infrastructure system.[6] Because of this potential level of contamination, surface water usually requires aggressive and sophisticated treatment prior to consumption. Groundwater may be contaminated from a number of natural sources, including arsenic, uranium, and radon resulting from local hydrogeology.[7] In addition, severe contamination of the soil, such as from hazardous waste dumps and leaking underground storage tanks, recent increases in unconventional oil and gas drilling, and extreme flooding events that overwhelm aging sewer systems, agricultural fields, and livestock farms, can lead to locally severe groundwater contamination.[8–10]

Upgrades to water infrastructure systems to meet current needs related to delivering safe drinking water and future needs under changed climate conditions will require major investments.[11] The EPA estimates that $472.6 billion is needed over the next 20 years to maintain and improve the nation’s drinking water infrastructure.[11] Of that investment, $312.6 billion (or 66% of the total) will be required to replace and refurbish aging or deteriorating pipelines alone, $83 billion to improve treatment infrastructure, $47.6 billion for storage infrastructure, and $21.8 billion for source intake structures.[11] In addition, $271 billion will be needed to repair or upgrade publicly owned wastewater conveyance and treatment facilities, combined sewer overflows, and stormwater management systems to protect water quality and public health.[11] These costs are expected to rise due to climate change impacts including lengthening of rainy seasons and extreme precipitation overwhelming reservoirs and sewer systems, particularly in urban areas; shortening and reduction of snow melts that provide source water; and droughts, which reduce water availability and diminish the structural integrity of concrete structures and dams.[12]

Individuals, particularly those living in low-income communities and those in rural, tribal, and immigrant or refugee communities near polluted source waters, fracking sites, and areas with an aging infrastructure that diminishes the capacity to deliver safe drinking water, may face increased exposure to unsafe drinking water. Tap water may be contaminated by chemical and biological hazards that cause acute and chronic diseases. In tribal communities, 1.9% of people lack access to a safe water supply and/or waste disposal facilities, nearly twice the percentage found in the general U.S. population. In addition, 17% of individuals lack general sanitation facilities, which could result in local pollution in communities with low access to health care. The investment to build sanitation facilities in American Indian and Alaska Native homes and communities would result in at least a 20-fold return in health benefits.[13]

The costs described here may create an undue economic burden for low-income and rural populations. In 2016, an estimated 15 million people in the United States experienced a water shutoff due to nonpayment. In addition, privately owned water systems are on average 59% more expensive than public water systems. In places where private systems are the only option, this may place a significant financial burden on low-income populations.[14] In American Indian and Alaska Native populations, existing infrastructure needs would cost an estimated $3.2 billion; an additional $2.4 billion would be needed over the next 20 years to repair or maintain tribal drinking water infrastructure.[15]

Many public water treatment systems and most private well systems are not equipped to treat or remove chemical contaminants such as perfluorinated chemicals, which have become nearly ubiquitous in U.S. water systems.[16] Properly treated water may become contaminated again after it leaves the treatment plant and enters the distribution system if the system is damaged. Outbreaks have been associated with contamination of water within distribution systems when sewage from wastewater pipes has entered drinking water pipes through leaks or improper connections.[2]

Specific contaminants of concern: Waterborne disease outbreaks can occur when water treatment and/or infrastructure systems fail or when untreated water is consumed. Data reported to the CDC from 2008 to 2014 show that bacterial etiological agents are far more prevalent than protozoa or viruses with respect to numbers of outbreaks as well as numbers of cases.[17] The highest numbers of cases reported for bacterial, protozoan, and viral agents involve Salmonella, Cryptosporidium, and norovirus, respectively.

In terms of outbreaks, Legionella, Giardia, and norovirus have the highest prevalence.[17] Groundwaters have been the source of the majority of outbreaks due to bacterial contamination. Most waterborne pathogens cause acute gastrointestinal illness, but some may function differently; for example, Legionella spp. can cause acute respiratory illness. The elderly and children are the most susceptible populations.[18] Infrastructure issues magnify the problem of microbiological contamination of our water supplies, as biofilms growing in distribution networks support the growth of opportunistic pathogens such as Legionella, Pseudomonas, and Mycobacterium.[19,20] Corrosion in older infrastructure contributes significantly to surfaces that can support biofilm growth.[20]

Due to the widespread use of chlorine in drinking water treatment, it is the most common point of exposure to chlorinated disinfection byproducts (DBPs), which are formed by reactions between chlorine and organic molecules.[21] Organics are typically naturally occurring (e.g., tannins come from the decay of natural organic matter such as leaves) and are therefore most likely to be found in surface waters. While a meta-study focusing on trihalomethanes and bladder cancer did not reveal any convincing connection, other DBPs such as haloacetic acids are still suspect in both cancer and noncancer health effects.[22] In addition, some studies have suggested an increased risk of adverse reproductive outcomes, including spontaneous abortions and neural tube defects.[23] In 2006, the EPA set health protective standards when it finalized rules requiring public water systems to comply with established maximum contaminant levels for DBPs and maximum residual disinfectant levels.[24]

Since the removal of lead from gasoline, drinking water has become a more important route of lead exposure for the general population. Lead generally enters drinking water by leaching from lead pipes, lead solder joints, older brass fixtures, and some pumps used for wells. Studies of fountains and other fixtures in offices and schools have shown a potential for high exposures to lead in first-draw samples of water.[25] There may be high amounts of lead in drinking water in older housing, particularly housing with lead distribution pipes. A continued failure to invest in infrastructure, particularly in communities where racial minorities and individuals with lower incomes predominate, has led to public health crises and widening health disparities across race and class, as demonstrated in Washington, D.C., and Flint, Michigan, among other areas.[26,27] Prenatal lead exposures and exposures among youths are known to affect brain development, resulting in lower cognitive function, lower IQ, and increased behavioral problems. Prolonged exposures can also result in hearing loss, tooth decay, spontaneous abortions, renal disease, and cardiovascular disease in adults.[28]

A variety of other metals, including arsenic, cadmium, mercury, and strontium, may be found locally in drinking water supplies. Arsenic in particular has been found in high levels in community and private water supplies, usually as the result of high concentrations in regional geological formations. Arsenic has been associated with bladder, skin, and lung cancers.[29] In 2001, the EPA set the arsenic standard for drinking water at 10 parts per billion.[30]

Nitrates and nitrites contaminate water supplies owing to ground applications of fertilizers and seepage from septic tanks. As a result, concentrations tend to be highest in rural, agricultural areas and may vary widely depending on the season. The number of people served by systems in violation of nitrate and nitrite standards fell from 1.5 million in 1997 to 200,000 in 2014; however, the EPA estimates that the percentage of systems in violation rose from 0.28% to 0.32% between 1994 and 2016.[31] Acute and long-term threats to public health include blue baby syndrome among exposed pregnant women and infants and increased risks for certain cancers and birth defects, respectively.[31]

Radon in water constitutes a threat to health from direct ingestion as well as inhalation from leaks and after water is heated and/or agitated, such as during showering. Alpha particles emitted from radon can cause cancer of the gastrointestinal tract or lung, depending on the route of exposure. Levels of radon vary regionally. Water from New England, the Southeast, and mountain areas may have more radon than water from other regions.[32] The EPA regulates radon in drinking water as an alpha emitter with a limit of 15 pCi/L. Some states have set a lower threshold, including Massachusetts at 10 pCi/L.[33]

Thousands of chemicals that pose potential risks to human health have been found in drinking water sources. A variety of pesticides are routinely found in drinking water at very low concentrations. Tetrachloroethylene, also known as perchloroethylene or “perc,” has been found in high levels in water supplies as a result of leaching from installed polyvinyl chloride water mains. Studies of populations exposed through this route have associated perc exposure with lung cancer and possibly colorectal cancer.[34] Migration of fuel-associated chemicals such as benzene and methyl-ter-butyl ether (MTBE) from underground gasoline storage tanks has also been reported.[35] Unconventional (“frac”) gas and oil exploration and extraction pose threats of contamination to both groundwater and surface drinking water sources. Such processes have been implicated in degradation of water quantity and quality. More than 1,000 chemicals are used in unconventional gas and oil exploration, with many lacking basic toxicity data. However, a number of known or suspected carcinogens, endocrine disruptors, and toxins have been found in drilling fluids and wastewater.[36,37]

An emerging threat to drinking water safety is from per- and polyfluoroalkyl substances (PFASs). With more than 6,000 individual chemicals, PFASs are used in a variety of products from firefighting foam to nonstick cookware and stain-resistant fabrics.[38] Animal studies have revealed that PFASs are potentially toxic to humans at extremely low doses, and epidemiological evidence shows an increased risk of cancer and effects on neurological development, immune function, and metabolic outcomes. Widespread groundwater contamination has been found near PFAS manufacturing sites in Michigan and elsewhere in the United States.[39]

Endocrine-disrupting chemicals (EDCs) found in pharmaceuticals and other products can enter drinking water sources from agricultural sources (e.g., atrazine) and human sources (e.g., personal care products) after upstream wastewater has been released and reenters the drinking water system through downstream intake. Thousands of EDCs enter product markets each year with little or no toxicological testing and have been found to be ubiquitous in humans and ecosystems.[40] Although the effects of long-term exposure from drinking water are unknown, EDCs can affect immune and reproductive development and systems (e.g., early puberty and infertility), cause neurobehavioral and neurodevelopmental changes, and affect human metabolism; they have also been linked to obesity in animal studies and cancers.[40] The most frequently detected compounds include atenolol, atrazine, carbamazepine, estrone, gemfibrozil, meprobamate, naproxen, phenytoin, sulfamethoxazole, tris(2-chloroethyl) phosphate, and trimethoprim.[41] Conventional treatments for wastewater have been found to be largely ineffective in removing EDCs, although partially activated charcoal and ozonation systems have been more successful. However, different compounds require different removal systems. For example, compounds such as DEET (N,N-Diethyl-meta-toluamide), ibuprofen, and gemfibrozil require ozonation to be removed during water treatment, while other compounds, such as atrazine, cannot be removed through current treatment technologies.[42]

Antibiotics have been instrumental in saving millions of lives, but today we are faced with the challenge of antibiotic resistance in our drinking water systems. Antibiotic-resistant bacteria originating from wastewater treatment, health care, agricultural, and industrial facilities often end up in our drinking water supplies. This issue is a global concern, and the World Health Organization has declared antibiotic-resistant bacteria an emerging pollutant and health threat in drinking water.[43]

Susceptible populations: When assessing drinking water quality, it is vital to consider populations that are more susceptible to exposures, including infants and children, immunosuppressed individuals, pregnant women, and the elderly. Neonates, for example, are especially at risk for enteroviruses, lead, mercury, nitrites, and nitrates.[44] Schools, day-care centers, and camps for children can be prone to outbreaks from waterborne Escherichia coli, Shigella, and viral contaminants.[45–49] The immune-suppressed population includes not only people living with AIDS but also transplant patients, people undergoing chemotherapy or taking other immune-suppressing drugs, and those suffering from less common congenital or acquired immune system dysfunction. Cryptosporidiosis is deadly for immune-compromised individuals. Transplant patients are especially susceptible to developing disseminated adenovirus infections.[50] The elderly are at increased risk of infection and disease from microbial contamination as a result of many factors, including reduced immunity, high incidence of frailty from malnutrition or existing chronic illness, and institutional exposure (e.g., exposures at hospitals and nursing homes). They are also at increased risk of dying from waterborne infections. The case fatality rates in nursing homes for certain waterborne pathogens, such as rotavirus and E. coli 0157:H7, can be two orders of magnitude greater than those in the general population. Outbreaks of Norwalk virus and other caliciviruses have been frequently reported in nursing homes.[51]

Evidence-Based Strategies to Address the Problem

It is timely for APHA to be actively engaged in policy activities related to safe drinking water. There are weaknesses in federal statutes and regulations governing the safety of drinking water, and a number of EPA standards are currently being reviewed and revised. There continues to be a significant gap in developing health-protective standards for chemical contaminants, and a lack of investment in water infrastructure combined with the increasing risk to drinking water sources and systems from climate-related damages raises the urgency of action needed to protect the public. Climate change is expected to exacerbate drought conditions in the U.S. West and increase extreme rain events in the eastern part of the country. Such changes not only threaten water availability but, if not managed, increase the risk of pollution of surface water and groundwater sources and damage to critical water treatment and delivery systems.[52] Significant costs are expected to prevent microbial and chemical contamination of source waters, provide continued maintenance of infrastructure required for safe delivery and successful treatment, and maintain protective infrastructure to adapt or mitigate climate impacts.[7]

Current EPA standards for chemical contaminants may not reflect the latest science and therefore may not sufficiently protect public health. For example, lead is known to bioaccumulate and have a number of health impacts, including reduced intelligence scoring in children and impaired reproductive function in adults.[53] The U.S. Primary Drinking Water Regulations standard sets a goal of 0 mg/L for lead but allows up to 0.015 mg/L before action must be taken.[54,55] This is in spite of ample evidence showing that no amount of lead in the blood can be described as safe and centralized water treatment can reliably manage lead to 0.010 mg/L.[55–57] In another example where U.S. water standards are inadequately protective of a vulnerable population, manganese has been shown to have neurological effects in the very young. As a secondary contaminant, manganese has only a nonenforceable guideline value of 0.30 mg/L for aesthetics.[58] Health Canada believes that manganese is much more serious and, in 2019, established a health-based value of 0.12 mg/L.[59] Moreover, although EPA standards aim to protect health, the decision to do so (and to what level) includes consideration of economic factors such as treatment costs.[60] A state can take action on its own to regulate contaminants if the EPA has not acted or has set a level higher than the state considers appropriate.[61] For example, the EPA regulates arsenic at 0.010 mg/L, while New Jersey has set the maximum level at 0.005 mg/L.[62]

Centralized treatment and distribution make it easier to monitor and control most contaminants in finished drinking water. Unfortunately, this is not always an option. Private homeowners, rural communities, and very low-income communities, for example, may simply not have the financial, staffing, or geographic resources to make central treatment/distribution possible. Public water systems are increasingly strained by treatment mandates and may lack the capacity to meet emerging threats. Furthermore, contaminants such as lead do not occur at the source but instead are derived from water’s contact within the distribution system and premise plumbing.[63,64] Applying a final barrier where the water is used is a critical alternative available to end users, regardless of whether they are on a community or private supply.[65,66] Laboratories accredited by the American National Standards Institute test, certify, and list devices that treat specific water contaminants at a dedicated faucet (point of use) or for an entire building (point of entry). Viable technologies include reverse osmosis (e.g., for metals, nitrates/nitrites), carbon in tanks or cartridges (e.g., for organic compounds), aeration (for radon), ultraviolet and hollow fiber membranes (for microbes), and specialized sorbents (for arsenic, perchlorate, MTBE, PFASs). Although it may be cost prohibitive for low-income populations, individuals are thus empowered to take protective action themselves, and some communities are using these options for regulatory compliance while retaining centralized control.[67]

One of the important public health provisions in federal legislation is ensuring people’s right to know what is in their drinking water. Under the Safe Drinking Water Act Amendments of 1996, water utilities are required to issue consumer confidence reports (CCRs) or right-to-know reports that disclose monitoring results for regulated contaminants. CCRs are good informational tools, but they do not give consumers the full picture on drinking water quality and have been shown to have important limitations. Local, state, and community public health experts and advocates can play a significant role in providing valuable research and engaging the public in educational efforts. For example, CCRs provide information only to people drinking from community water supplies; however, it is estimated that 15% of people in the United States (about 45 million residents) get their drinking water from private wells or other individual systems.[68] Only levels for regulated contaminants in public water supplies are reported, and some important contaminants are not regulated. Testing and reporting standards for privately owned water sources, not currently regulated by the EPA, should be required, and public health officials can help bridge the knowledge gap. Such efforts should be supported through government or foundation funding for local health departments or in partnership with institutes of higher education.

The EPA and state regulatory agencies need guidance from public health experts on the setting and implementation of drinking water standards. For example, public health expertise is greatly needed on setting appropriate standards for chemical and microbial contaminants, ensuring the protection of vulnerable populations, protecting drinking water sources, evaluating risk trade-offs between contaminants and between controlling contaminants and controlling costs, and participating in the broader public disclosure about drinking water quality.

Opposing Arguments/Evidence

It is difficult to imagine that anyone would oppose addressing drinking water contaminants; however, there is evidence that such opposition does exist. One of the primary health concerns regarding drinking water is exposure to chemical contaminants. There is increasing evidence of chemical contaminants in drinking water that threaten health and that current public water treatment systems are inadequate to remove. Responsible industries have for decades lobbied against more stringent drinking water quality standards. Recently, oil and gas interests have lobbied against addressing chemical contaminants related to unconventional oil and gas operations.[69] In addition, the Department of Defense has lobbied against appropriately low thresholds for per- and polyfluorinated chemicals.[70,71]. In 2019, the EPA determined that the cost of compliance for a perchlorate limit would not be justifiable, even though Massachusetts already successfully limits exposure to 2 ug/L.[72] In each instance, the argument has been that there is no evidence of health impacts from the chemicals, that measures taken by the industry are protective of human health and adequate to prevent health harmful exposures, or that a limit is too costly to implement. However, evidence of health impacts from exposure to chemicals of concern, for example PFAS chemicals, continues to mount. Proposed federal legislation in 2018 that might have expanded the EPA’s authority to protect water sources was heavily lobbied against by the electric utility, mining, and agricultural industries. Electric utilities spent $121.8 million, mining interests $23 million, and agriculture $126.4 million in 2018 alone.[73] Other industries that spent heavily on lobbying and showed an interest in the legislation included the oil and gas industry ($141.2 million) and the chemical industry ($64.9 million). The pharmaceutical industry has lobbied against local drug take-back laws that would prevent unused pharmaceuticals from being disposed of in trash or waterways.[74]

Meanwhile, these powerful lobbies have largely left the treatment of public water systems to drinking water providers. Community water providers argue that they do not have the funding to upgrade their systems or would unjustly raise costs for low-income consumers. Ultimately, households, local governments that own and manage public water systems, and businesses will be responsible for the additional costs.[75] For example, water mitigation systems range in cost from $500 for charcoal scrubbers that remove 75% of radon from water to $5,000 for aeration systems that remove 95% to 99% of radon.[76] In instances in which the occupants are tenants and not the primary owner, they must rely on property owners to pay for mitigation efforts. This could result in raised rents and an increase in housing expenses, which could in turn serve as a barrier to remediation if landlords are uncooperative.

Action Steps

The American Public Health Association seeks to promote the basic right of all people and all communities to safe and affordable drinking water. APHA urges:

The EPA, the CDC, and state and local environmental protection and health departments to:

  • Foster greater involvement of public health professionals as advisors, educators, and advocates on issues related to drinking water and health.
  • Promote understanding in public health practice and policy-making of the potential public health impact of drinking water contamination.
  • Ensure broader public access to information on drinking water quality, including improvements in consumer right-to-know provisions that will inform people of the quality of their drinking water.
  • Support community-based interventions that promote awareness of safe drinking water and initiate collaborative approaches to sustaining safe drinking water.
  • Set health-based standards or regulatory rules for contaminants such as lead and copper.
  • Prepare response plans for drinking water contamination.
  • Strengthen standards to protect water systems from contaminants from source waters to delivery systems, such as plumbing standards that result in zero lead exposure and removal of materials that threaten health from the marketplace.
  • Ensure that they are authorized to enter schools and child-care centers without prior notice to assess drinking water quality and access to safe and healthy drinking water sources.

Local, state, and federal governments to:

  • Increase funding for research on links between drinking water contamination and disease as a foundation for informed standard setting.
  • Increase funding for public health departments and other interested nongovernmental entities to educate the public about drinking water quality and to be prepared for public health emergencies related to drinking water.
  • Increase investments in infrastructure improvement, funded through increased taxation of polluting industries or holding those industries responsible for damages and pollution, including specific attention to affected rural and socioeconomically disadvantaged areas.
  • Increase funding to support collaborative work among government agencies that are integral to protecting public health across drinking water systems, such as the EPA, the Department of Housing and Urban Development, the Department of Agriculture, and the Department of Health and Human Services. Special attention and priority should be given to agencies serving vulnerable and economically disadvantaged populations, such as the Indian Health Service.
  • Ensure greater accountability of the EPA and state regulatory agencies in the prevention of waterborne diseases, especially among vulnerable populations such as children, the elderly, immune-compromised individuals, low-income communities, and communities of color, and increase authority and funding for investigative and regulatory action.

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