Water Boil Advisories

The United States May 2024 - May 2025: Causes, Geographic Distribution, and Frequency

A comprehensive overview of water boil advisories (BWAs) issued across the United States during the period of May 2024 to May 2025. It highlights the dynamic and often localized nature of these public health directives, emphasizing the primary drivers that necessitate their issuance. While the query sought a detailed summary of all advisories, a single, comprehensive national database for every BWA issued within this specific 12-month timeframe is not readily available in public sources. Data is fragmented across federal agencies, state environmental protection departments, and local water utilities, making a complete, real-time national aggregation challenging. Consequently, this report synthesizes available federal and state-level information, along with illustrative examples, to present a representative picture of the landscape of drinking water advisories.

The analysis reveals that water systems in the U.S. face a dual challenge: persistent, chronic issues such as aging infrastructure and physical disruptions, alongside a significant and escalating emerging threat from cybersecurity incidents. These factors contribute to a complex array of vulnerabilities that can compromise water quality and necessitate advisories. The report also addresses the inherent challenges in data transparency and accessibility, which can impede a holistic understanding of water safety incidents nationwide. Key observations underscore the critical need for enhanced water system resilience, including robust infrastructure investment and advanced cybersecurity measures, coupled with improved data sharing mechanisms to safeguard one of the nation's most vital resources.

The Critical Role of Drinking Water Safety

Access to safe and reliable drinking water is a fundamental pillar of public health and economic stability in any developed nation. Contaminated drinking water poses significant health risks, with the Centers for Disease Control and Prevention (CDC) estimating that at least 1.1 million people in the United States fall ill each year from germs present in drinking water. This persistent risk underscores the critical importance of robust water safety protocols and the timely issuance of public health advisories.

Drinking water advisories serve as essential public health tools, informing consumers about potential or confirmed contamination in their tap water and providing specific guidance to prevent illness. These directives are issued by governmental or health authorities when a community's drinking water is, or could be, compromised. It is crucial to understand the distinct types of drinking water advisories, as each addresses a different type of threat and requires a specific consumer response:

Boil Water Advisories (BWAs): These directives instruct consumers to boil tap water before consumption. They are issued when the water is or could be contaminated by pathogens such as bacteria, viruses, or parasites. Boiling effectively kills these disease-causing microorganisms.
Do Not Drink Advisories: These advisories are issued when tap water is, or could be, contaminated with harmful chemicals or toxins. In such cases, boiling the water is ineffective at removing the contaminants and can sometimes concentrate them, potentially exacerbating health risks. Commercially bottled water is typically recommended for drinking and cooking.
Do Not Use Advisories: Representing the most severe category, these advisories are issued when any contact with tap water—including swallowing, touching, or inhaling—could be dangerous due to severe contamination. Commercially bottled water is advised for all purposes.

The distinction between these advisory types is paramount for public understanding and appropriate action. For instance, misinterpreting a "Do Not Drink" advisory as a "Boil Water" advisory when chemical contamination is present could lead to continued exposure to harmful substances. This highlights the necessity for clear, unambiguous public communication and education campaigns regarding water safety.

Furthermore, it is important to recognize that drinking water advisories are primarily reactive measures. Their issuance signifies a detected risk or a failure within the water system, prompting immediate action to prevent illness. While essential for public safety, the need for such advisories points to underlying vulnerabilities in water infrastructure and operations. The overarching objective of water management is to prevent these incidents from occurring in the first place, thereby reducing the reliance on reactive public health warnings. This report will synthesize available information on U.S. water boil advisories from May 2024 to May 2025, offering insights into their causes, geographic distribution, and frequency, while acknowledging the inherent data aggregation challenges.

Understanding Boil Water Advisories: Public Health Directives

A Boil Water Advisory (BWA) is a specific public health directive advising consumers to boil tap water before consuming it. This advisory is typically issued when an event has occurred that creates the potential for biological contamination of the water supply, such as from pathogens or other microbiological indicators of sewage contamination. It is crucial to note that an advisory does not always mean the water is confirmed to be contaminated, but rather that it may be contaminated, necessitating precautionary measures.5 This reflects a precautionary public health approach, prioritizing safety in situations where the integrity of the water system has been compromised, even if direct pathogenic presence has not yet been confirmed.

The fundamental purpose of a BWA is to eliminate disease-causing organisms. Boiling water to a full rolling boil for 1 minute is the surest way to kill viruses, bacteria, and parasites. For communities at elevations above 6,500 feet, the lower boiling point of water necessitates a longer boiling time of 3 minutes to achieve the same disinfection effect. After boiling, the water should be allowed to cool before use to prevent burns.

During a BWA, consumers are advised to use commercially bottled water or boiled tap water for all ingestible purposes. This includes drinking, preparing and cooking food, making ice, and brushing teeth. For infants, ready-to-use formula is preferred, or formula prepared with boiled water. Handwashing can often be done with tap water and soap, but local official guidance should be followed. When bathing or showering, care must be taken not to swallow any water, and sponge baths are recommended for babies and young children to minimize ingestion risk. Dishwashers with a sanitizing cycle or a final rinse temperature of at least 150°F (66°C) are generally safe. For handwashing dishes, a bleach rinse (1 teaspoon of unscented household liquid bleach per gallon of warm water, soaked for at least one minute) is recommended after normal washing and rinsing. Laundry is typically safe to wash as usual.

A critical distinction to emphasize is that boiling water does not remove chemical contaminants or toxins. If the water supply is compromised by chemicals, such as per- and polyfluoroalkyl substances (PFAS) which affect millions of Americans, a "Do Not Drink" or "Do Not Use" advisory will be issued. Boiling water in such scenarios is not only ineffective but could potentially concentrate the harmful chemicals, increasing health risks. For example, the nationwide drinking water warning issued by the Environmental Protection Agency (EPA) in May 2024, stemming from cyberattacks, highlighted the alarming potential for hackers to alter chemical levels in water systems, which would necessitate a "Do Not Drink" advisory rather than a BWA.

Boil Water Advisories are typically lifted once the water system has returned to normal operating pressure and adequate disinfection has been restored. Following this, water samples are collected from the affected area and analyzed for coliform bacteria. Regulatory requirements mandate a minimum of 18 hours for coliform testing before results are released. The advisory can only be lifted if all water samples test negative for total coliform and the disinfectant residual (e.g., chlorine) is adequate. This mandatory testing period means that even for seemingly minor or quickly resolved incidents, affected populations must adhere to boiling instructions for at least 18 hours, imposing a significant burden on daily routines and potentially increasing reliance on bottled water.

Frequency and Scope of Advisories (May 2024 - May 2025)

Compiling a precise, comprehensive national summary of all water boil advisories issued across the United States within the past 12 months (May 2024 - May 2025) presents significant challenges due to the decentralized nature of water quality data reporting. There is no single, readily accessible public database that aggregates every BWA issued by thousands of individual water systems across the nation.

The EPA maintains the Safe Drinking Water Information System (SDWIS) Federal Reporting Services, which allows users to query data on public water systems, including compliance and violations. While this system contains extensive information, the available documentation does not explicitly mention aggregated reports or data summaries specifically detailing drinking water advisories or the incidents that trigger them for the 2024-2025 period. This lack of easily accessible, aggregated national BWA data, despite the EPA's own "Report to Congress: National Occurrence and Causes of Boil Water Advisories in the United States" published in May 2024, indicates a significant data transparency and accessibility gap. This makes it difficult for external analysts and the public to gain a holistic understanding of water safety incidents, potentially hindering data-driven policy decisions and resource allocation.

State primacy agencies, responsible for enforcing federal drinking water regulations, often maintain more detailed and up-to-date databases than the EPA's federal system. For instance, Louisiana's Safe Drinking Water Program tracks BWAs within its Drinking Water Watch database, listing them under the "Violations" section, even though BWAs themselves are not regulatory violations but rather precautionary measures. This state-by-state approach necessitates extensive individual compilation to build a national picture.

Despite the absence of a comprehensive national tally for the specific 12-month period, illustrative state-level data provides a sense of the high frequency of these advisories. In Texas, for example, there were at least 2,457 boil-water notices issued in 2022, averaging seven per day. This figure, while from a prior year, underscores the routine nature of such advisories in certain regions, particularly impacting rural areas. The Texas example also highlights a potential for underreporting at the state or national level; one utility's internal data indicated approximately six boil-water notices per month, while the state environmental agency had only tracked 50 of those notices for the same period. If such discrepancies are common across the country, the true frequency of BWAs nationwide could be considerably higher than what is captured in official aggregated statistics. This suggests that the scale of water safety challenges may be underestimated, impacting the perception of risk and the urgency for investment in water infrastructure.

Regarding the duration of advisories, BWAs typically last between 24 to 48 hours, though they can sometimes extend longer. The mandatory minimum 18-hour period for coliform testing before an advisory can be lifted contributes to this duration, even if the underlying issue is resolved quickly.5

A significant national event within the past 12 months was the nationwide drinking water warning issued by the EPA in May 2024, primarily in response to a series of cyberattacks targeting water and wastewater systems across the country. While this was a broad warning rather than a specific boil advisory, it signaled a pervasive national threat that could lead to widespread disruptions and the issuance of various types of water advisories, including BWAs, if treatment processes or distribution integrity were compromised.

Primary Causes of Boil Water Advisories

Boil water advisories in the United States are triggered by a range of factors, often reflecting both chronic infrastructure deficiencies and emerging threats. These causes frequently interact, creating complex scenarios that compromise water safety.

Infrastructure Failures

Aging infrastructure remains a pervasive and significant contributor to water quality issues, leading to a high frequency of advisories. Water main breaks are a common cause of BWAs, often resulting from the deterioration of pipes or damage during utility construction projects. For instance, in May 2025, parts of Wayne County, Indiana, were placed under a boil advisory following a water main break. Similarly, a faulty water valve along Northside Parkway in Atlanta, Georgia, caused an outage and subsequent boil water advisory in May 2025.

A critical trigger for BWAs is the loss of system pressure. When water pressure in the distribution system drops below 20 pounds per square inch (140 kPa), it creates a vacuum that can allow pathogens or other contaminants to enter the piped water system. This was a stated cause for a boil water advisory in Asheville, North Carolina, in October 2024, following Hurricane Helene. Another example occurred in Southwest Iowa in May 2025, where depressurization in the Regional Water system's towers led to a BWA, partly due to drought-impacted wells struggling to meet water demands. The analysis of boil-water notices in Texas in 2022 revealed that aging infrastructure, coupled with rising costs, left the state's water systems increasingly brittle, contributing to thousands of notices.This highlights a systemic vulnerability where the physical degradation of water systems directly leads to conditions necessitating public health warnings.

Microbiological Contamination

Direct detection of microbiological indicators, such as E. coli, or confirmed pathogens in the water supply, directly triggers boil water advisories. The CDC's National Outbreak Reporting System (NORS) tracks waterborne disease outbreaks across the U.S. While the most detailed outbreak data provided is for 2021, it indicates that drinking water was implicated in nearly one-third (15 out of 52) of reported outbreaks, accounting for 42% of associated cases and 54% of hospitalizations.

The most common cause of illness outbreaks linked to drinking water, particularly public water systems, is Legionella, which is also a leading cause of hospitalization and death from drinking water-associated diseases. Other common pathogens identified in drinking water outbreaks include Campylobacter, Giardia, Norovirus, Pseudomonas, and E. coli. These pathogens underscore the ongoing biological threats that water treatment and distribution systems must continuously manage.

Cybersecurity Incidents

An increasingly prominent and concerning cause of water system disruptions is cybersecurity incidents. In May 2024, the EPA issued a nationwide drinking water warning for the entire United States due to a series of cyberattacks targeting water and wastewater systems. These attacks, some attributed to state-sponsored groups, exposed critical vulnerabilities in the nation's water infrastructure. Alarming statistics reveal that 70% of U.S. water systems do not fully comply with the cybersecurity requirements outlined in the Safe Drinking Water Act.

The potential consequences of these cyberattacks are severe, ranging from the disruption of water treatment processes and damage to pumps and valves to the alteration of chemical levels to hazardous amounts. Such disruptions could lead to widespread water contamination and pose significant health risks. Specific incidents reported include a week-long outage of American Water's billing and customer account systems in October 2024 due to a cyberattack. In September 2024, a cybersecurity incident at the water treatment facility in Arkansas City, Kansas, necessitated a temporary switch to manual operations. Furthermore, multiple water and wastewater plants in Texas were affected by cyberattacks in early 2024, with hackers reportedly interacting remotely with supervisory control and data acquisition (SCADA) systems and arbitrarily adjusting settings. This elevates cybersecurity from a mere IT concern to a critical public health and infrastructure risk. The widespread non-compliance with cybersecurity requirements suggests a systemic vulnerability that could trigger advisories on an unprecedented scale, potentially even "Do Not Drink" advisories if contaminants are introduced or treatment is severely compromised. This makes cybersecurity a significant risk multiplier, capable of affecting any water system regardless of its physical condition.

Natural Disasters and Extreme Weather Events

Natural disasters and extreme weather events frequently disrupt water systems, leading to advisories. Drought conditions, for instance, can impact water supply and pressure, as seen with the May 2025 BWA in Southwest Iowa, where drought-impacted wells struggled to meet water demands, causing system depressurization. Hurricanes and other severe storms can cause widespread power outages, flooding, or direct damage to infrastructure, all of which can compromise water quality and pressure, necessitating BWAs. The Asheville, North Carolina, boil water advisory in October 2024 was a direct result of Hurricane Helene, which caused both loss of pressure in distribution pipes and increased particle levels in the water.

Other Contaminants (Leading to "Do Not Drink" Advisories)

While not typically triggering boil advisories, chemical contaminants represent another significant threat to drinking water quality, leading to "Do Not Drink" advisories. Per- and polyfluoroalkyl substances (PFAS), often referred to as "forever chemicals," are a widespread concern, with over 105 million people across the country potentially having drinking water contaminated at levels exceeding the EPA's 2024 standards. These chemicals are linked to serious health harms, including kidney and testicular cancer, endocrine disruption, and immune system suppression. Despite the EPA finalizing landmark regulations for six PFAS in 2024, there has been a proposed plan to eliminate or substantially delay these urgently needed protections. In New York, for example, over 1.3 million people could lose protection from PFAS contamination if federal limits are removed. It is crucial to reiterate that boiling water does not remove PFAS or other chemical contaminants; such situations require "Do Not Drink" advisories.

The various causes of water advisories are often interconnected, revealing a complex web of vulnerabilities within the nation's water infrastructure. For example, aging infrastructure, a chronic issue, makes systems more susceptible to pressure loss during extreme weather events or more vulnerable to physical disruptions that could be initiated by cyberattacks. This interconnectedness suggests that addressing one vulnerability, such as through comprehensive infrastructure upgrades, can have positive ripple effects on the system's resilience against multiple threats. This highlights a systemic risk within the water sector, necessitating holistic, rather than isolated, risk management strategies to build truly robust and safe water supplies.

Conclusions

The analysis of water boil advisories in the United States from May 2024 to May 2025 reveals a complex and dynamic landscape of water safety challenges. While a precise, aggregated national count of all advisories remains elusive due to decentralized reporting, the available data and illustrative examples underscore the persistent and multifaceted nature of threats to drinking water quality.

The primary drivers of boil water advisories are multifaceted, encompassing:

Aging Infrastructure: Water main breaks and loss of system pressure, frequently caused by deteriorating pipes and distribution networks, remain a dominant factor. The sheer volume of advisories in states like Texas highlights the widespread impact of underinvestment in infrastructure maintenance and upgrades.
Microbiological Contamination: The presence or suspected presence of pathogens such as Legionella, Campylobacter, and E. coli continues to necessitate precautionary boiling measures. The CDC's tracking of waterborne disease outbreaks underscores the ongoing biological risks that water treatment systems must mitigate.
Cybersecurity Incidents: An emerging and rapidly escalating threat, cyberattacks have prompted nationwide warnings from the EPA. The vulnerability of a significant portion of U.S. water systems to these attacks represents a critical systemic risk, capable of causing widespread disruptions and potentially leading to more severe "Do Not Drink" advisories if chemical levels are compromised.
Natural Disasters and Extreme Weather: Events like droughts and hurricanes can severely strain water systems, leading to pressure loss, infrastructure damage, and subsequent advisories.

A significant observation is the inherent data transparency gap. Despite the existence of federal reporting systems and reports, obtaining comprehensive, aggregated national data on boil water advisories for specific periods is challenging. This fragmentation hinders a complete understanding of the scope and frequency of these incidents, potentially impeding effective national policy responses and resource allocation. Furthermore, discrepancies between utility-level and state-level reporting suggest that the true frequency of advisories may be higher than officially captured statistics.

The interconnectedness of these causal factors is a crucial aspect of water system vulnerability. Aging infrastructure can exacerbate the impact of extreme weather events or make systems more susceptible to physical disruptions initiated by cyberattacks. This highlights that water safety is not merely a sum of isolated incidents but a systemic challenge requiring integrated solutions.

In conclusion, ensuring safe and reliable drinking water across the United States demands a concerted and multi-pronged approach. This includes sustained investment in upgrading and modernizing aging water infrastructure, bolstering cybersecurity defenses to protect critical operational technologies, and enhancing resilience against the increasing frequency and intensity of natural disasters. Concurrently, improving data collection, aggregation, and transparency at all levels of government is essential to provide a clearer, real-time picture of water quality challenges, enabling more informed decision-making and proactive measures to safeguard public health.