Drinking Water From Private Wells and Risks to Children

Approximately 23 million households in the United States obtain their water from private wells.¹  Water systems with <15 service connections or serving <25 people, including private wells, are not subject to federal and state regulations under the Safe Drinking Water Act of 1974 (Pub L No. 93-523), nor are Native American reservations (each of which has its own Environmental Protection Agency [EPA] office). Households using private wells and small water systems that do not meet federal regulations for size are individually responsible for routine testing to ensure water is potable.

Groundwater is water that infiltrates into the ground and exists in the open space between soil particles and fractures in bedrock. As it infiltrates, some is held in the soil, some is taken up by plants, and the rest reaches the water table, in which all of the pore spaces and fractures are completely filled (saturated) with water. Below the water table, there may be several additional geologic units that are saturated; some are considered aquifers. An aquifer, which may or may not be the water table, is a geologic unit (either unconsolidated sand and gravel or bedrock) that can provide a usable quantity of water to a well. Aquifers receive recharge through infiltration from the surface or from the movement of water between geologic units, including other aquifers. As part of the hydrologic cycle, groundwater is continually moving both into (infiltrated) and out of (discharged to streams, pumping, springs) the ground and its volume can vary from season to season and year to year. An “artesian well” has a water level that is higher than the top of the artesian aquifer itself because of pressure in the aquifer.

There are 3 main types of water wells: large-diameter dug or bored wells, sand and gravel wells, and bedrock wells. Bedrock wells are typically drilled into bedrock, and the fractures in the rock act as a conduit to provide water to the well. Sand and gravel wells are generally either drilled or driven and completed in a geologic unit comprising sand and gravel. Sand and gravel wells typically have a screen at the lower 5 to 10 feet of the well, and water comes into the well through the screen. Driven sand and gravel wells (commonly referred to as sand points) are usually installed where sand is near the surface and the water level is shallow. Sand points do not protect from nearby surface contamination because of the high infiltration attributed to sandy surface soils, allowing surface contaminants to reach the well. Large-diameter dug or bored wells are generally installed when there is no aquifer available at the well location and, instead, are built to capture water from the shallow water table. Large-diameter wells are typically 3 or 4 feet in diameter to provide more volume in the well casing to store water that slowly infiltrates into the well from finer, less-permeable materials. Large-diameter dug and bored wells are typically shallow and, therefore, more susceptible to surface influences (eg, contamination, drought).

The natural chemical composition of well water varies with region, underlying geologic formation, and type of aquifer. In addition, anthropogenic contamination is dependent on nearby land uses, surface geology and soil type, industry practices, and the diligence of those storing, using, and disposing of potential contaminants. Some constituents of concern in groundwater can be harmful and have detrimental health effects. Others are merely undesirable because they can cause unwanted aesthetic effects (taste, odor, staining, etc). For example, iron is not a health risk and is necessary to our diet but, in water, it can cause staining of clothes and porcelain, making it undesirable in well water. Many other chemicals, some of them potentially toxic, can contaminate well water, with their presence or absence attributable to naturally occurring geologic factors or contamination from industry, farms, or business (Table 1). Pollutant chemicals in well water include nitrate and nitrite, heavy metals, organic chemicals, including pesticides, and radionuclides.

Calcium and magnesium carbonate determine water hardness. Hard water is not toxic, but it may require treatment to prevent precipitated minerals from clogging pipes and causing other problems, such as coating electric hot water heater elements and causing them to burn out. Hard water also affects the performance of soap and detergents. Manganese and iron can appear as rust-colored to black flecks and can stain clothing, plumbing, and fixtures; both are common in groundwater.

Microorganisms, including bacteria, viruses, fungi, and parasites, can contaminate the groundwater that supplies wells (Table 2). The major source of these organisms is fecal material from animals and humans. Analyzing well water at its point of use for “total coliforms” is the most common way of detecting fecal contamination of the water. When available, testing for fecal coliforms and/or Escherichia coli may be performed as a combined assay with total coliforms. Samples that contain any coliforms should be retested to determine if they are fecal coliforms; specimens that test positive should be examined for the presence of E. coli or other pathogens. More information is available at: https://www.health.state.mn.us/communities/environment/water/wells/waterquality/bacteria.html.

Other microorganisms can also pose a threat to a family’s health. So-called iron bacteria are a common cause of odor and taste issues with water. They can form visible black slimy colonies of microorganisms called biofilms, sometimes clogging pipes and faucets and harboring other harmful bacteria. More information is available at https://www.health.state.mn.us/communities/environment/water/wells//waterquality/ironbacteria.html.

Much of the information describing the pathogens that can be present in well water has been obtained from investigations of waterborne outbreaks, although waterborne illness is underrecognized and underreported. According to the Centers for Disease Control and Prevention (CDC), there were 42 waterborne disease outbreaks reported in the United States from 2013 to 2014, causing 1006 cases of illness, 124 hospitalizations, and 13 deaths.² Legionella species were associated with 24 (57%) outbreaks and all the deaths; 8 (19%) of the outbreaks were associated with Cryptosporidium species and Giardia duodenalis (also referred to as Giardia intestinalis or Giardia lamblia). Most outbreaks (83%) were associated with regulated, public water systems and 3 (7%) were associated with unregulated, individual systems. Of the 10 outbreaks found to be associated with wells, only 1, an outbreak of Campylobacter jejuni, was associated with a well at a private residence.²  Recent literature has documented the detection of antibiotic-resistant bacteria in contaminated water.³ 

Changes in the climate are a threat to the provision of safe drinking water to families who use private wells. These families depend on clean groundwater. Dynamic hydrological changes induced by changes in climate can impact adversely the aquifer and the quality of the water drawn from it, changing its salinity and/or mineral content and even introducing new chemical or microbial contaminants. The increasing frequency of extreme weather events, such as hurricanes and storm-related flooding, can contaminate groundwater with microorganisms and/or chemicals. Likewise, extreme weather conditions, such as prolonged lack of rainfall and, over time, the consequent occurrence of chronic drought conditions, can change the level of the water table and reduce the availability of groundwater for extraction by a private well. Such conditions can even lead to a dry, unusable well or changes in water quality because the introduction of air to previously saturated geologic materials can lead to the release of metals and other natural contaminants.

Wells can also be contaminated with chemicals and/or microorganisms as a result of flooding or extreme precipitation events or other natural disasters. For example, a review of 100 years of waterborne outbreaks related to extreme water-related weather events around the world revealed 83 published reports; contaminated drinking water was documented in 53.7% of cases.⁴  A study of surface water samples obtained after storm-related flooding of the Ohio River in Kentucky in the Spring of 2011 found elevated levels of both common pathogens such as E. coli, E. coli O157-H7, Salmonella species, Campylobacter species, and adenovirus, as well as contamination with metals (eg, arsenic, copper, iron, lead, and zinc) compared with water samples obtained 3 months later.⁵ 

Emergencies involving the release of radioactive substances can also impact sources of potable water. For example, the Fukushima earthquake and tsunami in Japan in 2011 triggered a nuclear plant blast as a result of a lack of power to properly cool the nuclear reactor components.⁶  The blast contaminated a wide swath of land with radioactive nuclear material. Levels of radioiodine and radioactive cesium were elevated in tap water sampled in Fukushima City a few days after the nuclear plant explosion, although they declined to nondetectable levels within 2 months. Chemical-biological terrorism and other manmade catastrophes can also affect drinking water. American Academy of Pediatrics (AAP) policies on chemical-biological warfare⁷  and radiation emergencies⁸  include relevant information on the contamination of drinking water by radioactive substances. The role of the pediatrician may include educating families about preparations in case of flooding and other disasters. Families should be urged to keep children out of flooded areas, and children should not be involved in clean-up efforts. Families should talk to their children about disaster preparedness using the AAP’s Family Readiness Kit and many pages with relevant information on the AAP website: www.healthychildren.org. Details about how pediatricians can help children and families respond in the aftermath of a disaster can be found on the AAP Health Initiatives website (https://www.aap.org/en-us/advocacy-and-policy/aap-health-initiatives/Children-and-Disasters/Pages/AAP-Policy-and-Publications.aspx). Specific guidance on what those who depend on private wells for drinking water can do in case of a flood or another type of disaster can be found on the CDC website (https://www.cdc.gov/healthywater/emergency/drinking/private-drinking-wells.html).

Hydraulic fracturing, otherwise known as “fracking,” is a technique used to extract oil or gas from underground rock formations. Hydraulic fracturing fluid is injected into oil or gas production wells under high pressure to fracture oil or gas-bearing rock. These fractures are propped open with various components of the hydraulic fracturing fluid known as proppants. Once pressure is removed, oil and gas are then free to move through the fractures and up the well to the surface for collection. Hydraulic fracturing fluids are typically made of water, proppants, and chemical additives, many of which are toxic to humans, including known carcinogens and endocrine disruptors. The EPA has previously concluded that fracking can impact groundwater resources under certain circumstances. Between 2000 and 2013, ∼3.6 million people obtained their drinking water from private wells in counties with at least 1 hydraulically fractured well.⁹  Approximately 17.6 million people in the United States live within 1 mile of an active oil or natural gas well.¹⁰  There is epidemiologic evidence of health effects associated with proximity to fracking operations and a serious concern for the potential for other health effects not yet characterized.

Every child deserves the provision of unlimited access to safe, clean drinking water. Yet there exist social and economic inequities in the location of housing of vulnerable families, for example, those living near toxic waste sites, industrial concerns, fracking operations, agricultural runoff, and other manmade threats to the purity of available groundwater. Families living in poverty are disproportionately impacted by the effects of climate change and natural disasters, such as hurricanes, tornados, floods, earthquakes, and wildfires, all of which can damage wells and disrupt the provision of safe drinking water. Such disparities impair the ability of vulnerable families to provide safe water to their children, making this an issue of environmental justice. The EPA has defined environmental justice as “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. This goal will be achieved when everyone enjoys the same degree of protection from environmental and health hazards, and equal access to the decision-making process to have a healthy environment in which to live, learn, and work.”¹¹ 

A properly constructed and sealed well should mitigate contamination from any surface source in most cases. Most near-surface contamination occurs because of poor well construction, improperly sealed wells, breached wells, or older wells that were not constructed to meet today’s code of standards. Chemical contaminants are approached by investigating the possibility that the contamination exists on the homeowner’s or on an adjacent homeowner’s property, such as from agricultural application of nitrogen-containing fertilizers, pesticide applications, or fuel tanks. If the water supply cannot be remediated further (ie, modify the well to prevent near-surface contamination or eliminate the source of contamination) and the well is still contaminated or the contaminants in question are naturally occurring, then it is possible to filter out or treat for virtually any chemical or biological contaminant. However, treatment can become complex and/or expensive and can require professional maintenance. Because there are no standards for private wells for many contaminants of concern, those seeking guidance to indicate potability have little choice but to apply the same standards that municipalities do under the Safe Drinking Water Act Amendments of 1996 (Pub L No. 104–182).¹²  For the current list of regulated drinking water contaminants, see https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations. Municipalities regard water that is persistently above these federal standards as not potable; noncompliant municipalities face fines and legal action from their state. Nonetheless, residential well owners are under no obligation to apply this same standard to their well water.

If test results confirm bacterial contamination, the water system must be treated. The first approach is to inspect the well to make sure that there are no structural defects that may have fostered the contamination. “Shock chlorination,” using concentrations of chlorine that are 100 to 400 times the amount found in municipal water supplies, should be performed initially. This procedure should be performed only in consultation with the health department or other experienced individuals. Most other treatment measures also require the services of a trained home water treatment professional. If bacterial contamination persists despite short-term remedies like shock chlorination, natural or structural factors may be present that may not be under the control of the well owner. This may require that a continuous disinfection treatment be added (eg, chlorination or UV light disinfection) or that the well be closed and a new well drilled. A certified well contractor should properly “abandon” the contaminated well if another well is drilled.

Details of contamination risks and the use of private wells for drinking water are provided in the technical report accompanying this policy statement.¹³  The reader is also referred to the AAP Handbook on Environmental Health, Fourth Edition, for further information on safe drinking water¹⁴  and the AAP Red Book: 2021 Report on the Committee on Infectious Diseases, 32nd Edition for further information on microorganism water contaminants.¹⁵ 

1. Pediatricians should familiarize themselves with issues, such as climate change, fracking, weather-related and other disasters, and other threats to clean groundwater and how such potential threats impact the provision of safe drinking water for children and their families who depend on private wells. Details of such issues can be found in the accompanying technical report.

2. Pediatricians should become familiar with well water considerations in their practice area and advocate at the community, state, and/or national levels for safe water practices that will protect the health of children. The 2 most common threats to the health of private well users are poor well construction and a lack of well owner knowledge. Pediatric care providers can be effective communicators when they partner with local and state public health authorities in counseling families and communities about routine and periodic well water testing. Resources listed in the technical report, including EPA and CDC websites, include helpful guidance and information about using a private well as a source of drinking water. The AAP website, HealthyChildren.org, contains guidance for parents on drinking water safety (see https://www.healthychildren.org/English/healthy-living/nutrition/Pages/Choose-Water-for-Healthy-Hydration.aspx).

3. Pediatricians are encouraged to ask whether a family drinks water from a private well at home, on vacation, when traveling, in childcare, or at other locations in which they might drink water. This is particularly important for families with an infant or a pregnant woman living in the home. Pediatricians should also clarify with families whether they just use the well water for cooking and bathing but use an alternative water source for drinking. If the well water is not safe for drinking, it should not be used for cooking either. Boiling the water only concentrates such contaminants as metals or nitrate. Families with a private well who have young children or those of high school age should follow the well water testing algorithm in Supplemental Figure 1. When local or state authorities provide further guidance with additional testing or an increased frequency of testing, such guidance should be followed.¹⁶  For a list of state private well drinking water programs, see https://www.epa.gov/privatewells/private-drinking-water-well-programs-your-state. Families are also advised to consult professionals with expertise in the construction, remediation, and maintenance of wells when the need for such services arises. A description of the tests and some rationale for their use are provided as follows.

4. Routine Testing

   • Purchase of a New Home with a Well

     The builder should provide the results of coliform, nitrate, inorganic (total dissolved solids, iron, manganese, magnesium, calcium, chloride), fluoride, radon, perfluoroalkyl and polyfluoroalkyl substances, arsenic, chlorinated hydrocarbons, and lead testing. If the home is near agricultural operations, then additional testing for pesticide residues is important. If the home site is near natural gas extraction (“fracking”) operations, then additional chemical tests of the well water, including testing for benzene, should be performed. If the well was shock-chlorinated after drilling, it should be retested for coliforms after some period of time as recommended by the local health department or agricultural extension agent. Have the builder or agent provide a site plan with the well, its water lines, and the septic tank and field.

   • Purchase/Rental/Lease of an Existing Home with a Well

     The well and septic field should be included in any general home inspection. If this cannot be performed, families should arrange for well inspection and testing as described in A above and have the septic tank located and inspected to determine if it needs to be pumped. If there are filters, softeners, or other devices in the water supply lines, determine from the seller or landlord what they are treating and the maintenance needs for the equipment.

   • Vacation Homes, Camps, etc

     A vacation home or camp with a well and no other water source should be tested each season. Every well should be tested, and there are procedures for properly shutting down and restarting a water system that is only in use for part of the year. For a short stay, if the quality of the well water cannot be ensured, it may be safer and more convenient to use commercially available bottled water for drinking and cooking for everyone.

   • Childcare and School

     Childcare in rural and suburban settings may use a private well for drinking water, and parents should inquire about the childcare center’s water source. If the water comes from a well, parents should ask whether the well has been regularly and recently tested for nitrate and coliforms and what the results were. If results are not available, infants should be given commercially available bottled water until the well water is shown to be safe. Today, many states require licensed childcare facilities to test their well water annually.

   • Scheduled Testing

     Every spring, the well should be examined to make sure that there are no mechanical problems. Well water should be tested annually for coliforms and nitrate. Testing more than once per year may be warranted in the following special situations: (1) someone in the household is pregnant or nursing, (2) there are unexplained illnesses in the household, (3) neighbors find a dangerous contaminant in their well water (in which case the homeowner’s well should be tested for that specific contaminant), (4) there is a change in the odor or taste of the well water, (5) there is a chemical spill in the proximity of the well, (6) there are new fracking operations, underground chemical storage tanks, or other commercial/industrial concerns in the vicinity that may pose a hazard of groundwater contamination, (7) there was a significant repair or replacement in the well, (8) there was a flooding event or another disaster resulting in possible well contamination.

   • Special Testing

     Routine testing for Giardia and Cryptosporidium organisms is not recommended because of the technical difficulty (filtering large volumes of water) and expense. To have these organisms in well water means there is a pathway into the well; usually annual testing for coliforms will reveal that possibility. It may be prudent to test for these parasites in the following situations: (1) if members of a family have developed gastrointestinal disease attributable to Giardia and/or Cryptosporidium species, (2) if the well is shallow or large diameter and the likely source of water is the water table itself, (3) if the well construction is inadequate and does not meet the current code, or (4) if an inspection reveals that the well is not properly sealed at the wellhead and is, therefore, not safe from surface sources and runoff. Wells that are in rural areas in which animals graze, including ranches and commercial concentrated animal feeding operations, can be especially vulnerable to such surface sources if they are not properly constructed and sealed. The risk factors for E. coli O157:H7 and other Shiga toxin-producing E. coli serotypes are similar to those for Giardia and Cryptosporidium species. When these situations exist, vigilance should be maintained for E. coli O157:H7 contamination and/or clinical symptoms. The time of annual testing for nitrate and coliforms is a reminder to check with the local health department about any water quality problems that have emerged.

5. Occasional Testing

   • New Pregnancy or New Infant

     A new infant or a child <1 year of age in the home or the presence of a pregnant woman should prompt testing if the yearly test has indicated any fluctuation in nitrate concentrations or has never been performed. Even a breastfed infant may need water at some time, and boiling does not remove and can concentrate nitrate or lead.

   • Damage or Disturbance to the Well

     If a new submersible pump is installed or the well integrity is compromised, such as by a falling tree, a vehicle collision, a flood, a fire, or a cut to the water line during landscaping, the well should be tested and, if necessary, shock chlorinated..

   • Sentinel Illnesses

     Not every episode of gastroenteritis requires an investigation of a private well or well testing as the cause of the illness. However, if multiple individuals become ill with gastroenteritis, if the gastroenteritis is recurrent, or if a pathogen causing the gastroenteritis is a bacteria or parasite that may have been present in the well water as a result of fecal contamination, then well testing for pathogens is indicated. Any occurrence of methemoglobinemia in an infant consuming well water requires testing the well water for nitrate.¹⁷  An elevated blood lead concentration in a child living in a home built after 1978, or a persistently elevated blood lead concentration, might prompt testing for lead in well water at the well spigot and a household faucet. At some point in the evaluation of unusual or cryptogenic illness, the possibility of contaminated well water should be considered.

6. Fluoride is an acceptedpreventive for dental caries, and if a child’s drinking water contains little or none, then supplements (available as drops or chewable tablets) are necessary. The AAP recommends no fluoride supplementation before 6 months of age; from 6 months to 3 years of age, children (including those who are breastfed) require fluoride supplementation if the water has a fluoride concentration of <0.3 ppm.^18,19  Supplementation from 3 to 16 years of age is recommended when drinking water fluoride concentrations are <0.6 ppm. The optimal fluoride level in drinking water is 0.7 ppm to avoid tooth decay.^18,19  In areas in which naturally occurring fluoride levels in drinking water exceed 2 ppm, people should consider an alternative water source or home water treatments to reduce the risk of dental fluorosis in children <8 years of age. Well water should be tested for the level of fluoride; this testing is most commonly performed through the health department.

7. Pediatric health care providers can also counsel families about other household practices to ensure safe drinking water, such as running the first morning draw of tap water for several minutes before use for cooking, drinking, and/or making baby formula to clear any lead that may have leached into it from older household plumbing overnight. Families can be advised about point-of-use, ANSI/NSF-certified filtration devices. These include attachments to faucets, water pitchers, or in-refrigerator water-dispensing features. Their purpose is to filter out any remaining impurities such as lead in tap water before consumer use for drinking or cooking.²⁰  Their effectiveness is variable depending on the contaminant of concern; regular maintenance and changing of filters are important for optimal filtration. Families can be referred to other sources of reliable information on home water filtration systems.²¹ 

8. The AAP has set forth principles in its Equity Agenda that include the statement: “child and adolescent health care professionals shall address the social, behavioral, and environmental factors that affect children’s health, development, and achievement.” Pediatricians are encouraged to advocate for those families in their community dependent on private wells who may be impacted by social or economic disparities in their ability to provide safe drinking water for their children.

1. Local governments are encouraged to provide access to information about local groundwater conditions. Recommendations for testing can be easily made available with a telephone call or a website visit. If water contamination becomes a public health issue, then multiple means of alerting and informing the public can be pursued.

2. Local, state, and federal governments and health policymakers should recognize and address the potential effects of climate change on the availability of potable water from private wells. Climate change planning should include strategies to safeguard groundwater from increasing natural contaminants, changes in salinity, reductions in the water table, and other long-term effects of dynamic changes in climate.

3. In areas in which agricultural land is being developed, fracking operations are planned, or land is put to any other new use, local governments are encouraged to notify homeowners with permitted wells regarding their policies and recommendations concerning well testing and the possibility of their well water being affected by the new use. State governments should require that the chemical content of hydraulic fracturing fluids be on file with the government so that when health or water supply issues arise, appropriate water testing can occur.

4. In agricultural areas in which livestock, pesticide, and fertilizer nitrate contamination of groundwater is a possibility, local or state governments are encouraged to notify homeowners with permitted wells regarding their policies and recommendations concerning the frequency and details of well testing. Such agricultural activity includes concentrated animal feeding operations.

5. Tests determined to be necessary for the safety and health of a family’s drinking well water should be convenient and, if possible, free or inexpensive. Some states provide support for private well testing; such programs are encouraged.

6. For housing that has drinking water supplied by a private well, states are encouraged to require testing for coliforms, nitrate, fluoride, perfluoroalkyl and polyfluoroalkyl substances, and any contaminant of local concern when a dwelling is sold, and the results ought to be made available to the buyer before closing. Private wells should be tested annually for the presence of coliform bacteria and nitrate. Wells should also be tested every 3 to 5 years for hardness, pH, turbidity, chloride, and the presence of metals and, if indicated, chemicals. State and local health department officials can offer advice about the advisability of testing for other contaminants, such as perfluoroalkyl and polyfluoroalkyl substances, pesticides, or fracking chemicals.

Alan D. Woolf, MD, MPH, FAAP Bryan D. Stierman, MD, FAAP Elizabeth D. Barnett, MD, FAAP Lori G. Byron, MD, FAAP

Aparna Bole, MD, FAAP, Chairperson Sophie J. Balk, MD, FAAP Lori G. Byron, MD, FAAP Gredia Maria Huerta-Montañez MD, FAAP Philip J. Landrigan, MD, FAAP Steven M. Marcus, MD, FAAP Abby L. Nerlinger, MD, FAAP Lisa H. Patel, MD, FAAP Rebecca Philipsborn, MD, FAAP Alan D. Woolf, MD, MPH, FAAP Lauren Zajac, MD, MHP, FAAP

Kimberly A. Gray PhD – National Institute of Environmental Health Sciences Jeanne Briskin – US Environmental Protection Agency Nathaniel G. DeNicola, MD, MSc – American College of Obstetricians and Gynecologists CDR Matt Karwowski, MD, MPH, FAAP – Centers for Disease Control and Prevention National Center for Environmental Health and Agency for Toxic Substances and Disease Registry Aaron Briggs, MD – Section on Pediatric Trainees Mary H. Ward, PhD – National Cancer Institute

Paul Spire

Yvonne A. Maldonado, MD, FAAP, Chairperson Sean T. O’Leary, MD, MPH, FAAP, Vice Chairperson Monica I. Ardura, DO, MSCS, FAAP Ritu Banerjee, MD, PhD, FAAP Kristina A Bryant, MD, FAAP James D. Campbell, MD, MS, FAAP Mary T. Caserta, MD, FAAP Chandy C. John, MD, MS, FAAP Jeffrey S. Gerber, MD, PhD, FAAP Athena P. Kourtis, MD, PhD, MPH, FAAP Adam J. Ratner, MD, MPH, FAAP José R. Romero, MD, FAAP Samir S. Shah, MD, MSCE, FAAP Kenneth M. Zangwill, MD, FAAP

David W. Kimberlin, MD, FAAP – Red Book Editor Elizabeth D. Barnett MD, FAAP – Red Book Associate Editor Ruth Lynfield, MD, FAAP – Red Book Associate Editor Mark H. Sawyer, MD, FAAP – Red Book Associate Editor Henry H. Bernstein, DO, MHCM, FAAP – Red Book Online Associate Editor

Karen M. Farizo, MD, US Food and Drug Administration Lisa M. Kafer, MD, FAAP, Committee on Practice Ambulatory Medicine David Kim, MD, HHS Office of Infectious Disease and HIV/AIDS Policy Eduardo López Medina, MD, MSc, Sociedad Latinoamericana de Infectologia Pediatrica Denee Moore, MD, FAAFP, American Academy of Family Physicians Lakshmi Panagiotakopoulos, MD, MPH, FAAP, Centers for Disease Control and Prevention Laura Sauvé, MD, MPH, FRCPS, Canadian Pediatric Society Neil S. Silverman, MD, American College of Obstetricians and Gynecologists Jeffrey R. Starke, MD, FAAP, American Thoracic Society Kay M. Tomashek, MD, MPH, DTM, National Institutes of Health Melinda Wharton, MD, MPH, Centers for Disease Control and Prevention

Jennifer M. Frantz, MPH

The authors would like to acknowledge with gratitude the contributions of Mr Steven Wilson, a groundwater hydrologist, who reviewed the manuscript, offered advice on needed revisions, and provided invaluable insights.

AAP

American Academy of Pediatrics

CDC

Centers for Disease Control and Prevention

EPA

Environmental Protection Agency