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Understanding Public Water Systems

Notifications from Public Water Systems Help Ensure Timely Alerts of Public Drinking Water Problems

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Updated:

July 15, 2024

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Most Americans use public water systems regularly, serving over 286 million Americans with tap water daily. Over 170,000 public water systems exist in the United States, including municipal water authorities, mobile home parks, campgrounds, and hospitals. These systems gather water from either surface sources such as lakes, rivers, and reservoirs, or groundwater aquifers. The public water providers must monitor and treat the water to ensure it is safe for all users and notify customers of any contaminants they discover during required water quality monitoring.

According to the EPA, a public water system includes any water supply source with 15 or more service connections or serves at least 25 people daily for at least 60 days of the year. Each type of water system can have different drinking water standards depending on the type and size of the system, but all require regular monitoring to ensure the water they provide is safe to drink.

Safe Drinking Water Act

The National Safe Drinking Water Act (SDWA) was initially passed in 1974 to help protect public drinking water in the United States from source to tap. It allows the EPA to set and regulate standards for currently over 90 contaminants that are known to be found in drinking water. These contaminants come from various sources, including chemicals, animal waste, pesticides, and naturally occurring substances. The SDWA protects drinking water by establishing limits called maximum contaminant levels or MCLs, the specific contaminant it regulates to keep drinking water at safe levels. The SDWA requires Public Water Systems to monitor and test to ensure their drinking water does not exceed these limits.

The Safe Drinking Water Act requires public water systems to send notifications for specific situations if a violation occurs. The notification system’s primary purpose is to alert the public about various violations or conditions that could potentially affect public health and safety. The EPA classifies these violations/situations into three categories based on the degree of risk they pose:

Tier 3 poses no direct risk to public health.
Tier 2 poses the potential to cause chronic human health conditions if exposed long-term.
Tier 1 poses adverse health side effects with immediate exposure.

Types of Violations

Tier 1 violations are the ones that require immediate action and, therefore, require water authorities to report these issues to the public within 24 hours. Announcements usually go out via phone, email, or a news release. The following are examples of Tier 1 violations:

Violation of the E. coli MCL (maximum contaminant limit)
Violation of the nitrate/nitrite MCL
Violations for chlorine dioxide exceed the MRDL (maximum residual disinfectant level) for two consecutive days
Violations of the turbidity MCL for two straight days
Violation of a treatment technique requirement for pathogenic bacteria, viruses, and protozoan cysts
Violation of a treatment technique requirement for Cryptosporidium
Detection of E. coli in source water samples
A breakdown in treatment for groundwater sources.
Occurrence of a waterborne disease outbreak that affects water quality and poses an immediate threat to human health
Other violations or situations that may pose a severe and immediate threat to human health

Tier 2 violations are less severe than tier 1 ones but still threaten human health if not dealt with quickly. Water authorities are required to notify the public within 30 days of a tier 2 violation or situation. The following are examples of tier 2 violations.

All violations of the primary MCL, MRDL, treatment technique requirements, and failure to take corrective action, except where a tier 1 violation notice is required
Violations relating to monitoring requirements, lead and copper, and additional requirements for groundwater sources where potential health impacts are possible
Failure to comply with the terms and conditions of any variance or exemption in place
Any other violation that poses a potential chronic health risk

Tier 3 violations are the least serious and pose no threat to public health. As a result, the EPA only requires water authorities to alert the public within a year of any of these violations or situations. Examples of tier 3 violations/situations are:

Monitoring violations not serious enough for tier 1 or 2
Reporting and recording maintenance violations for systems recycling their waste streams
Operation under a variance or exemption granted
Availability of unregulated contaminant monitoring results
Failure to report an E. coli MCL violation of an E. coli-positive sample
Failure to submit a completed assessment form

Common Public Notifications

Boil Water Advisory: A public notification that advises the customer to boil all tap water before drinking or cooking. This advisory is generally due to bacteria, virus, or parasite contamination. Boiling the water will help kill off any living organisms in the water and ensure it is safe to drink. Ensure that the water has reached a rolling boil for at least one minute to kill off all organisms, and then let the water cool before using if needed. This water can now be a safe drinking water alternative to tap water until the advisory concludes. Once the water is safe to use again, the water system will notify each affected customer and let them know if flushing of pipes is required.

High Contaminant Levels: A public notification that alerts customers of a high reading for a specific contaminant. If a public water system finds a contaminant above an MCL, it must alert its customers of the findings. The notification usually includes information about the harmful effects of the contaminant and action steps to take. Unlike boil water advisories, it is generally not recommended to boil water during this time as it may concentrate the contaminant. Instead, water users should refrain from using this water until the problem is solved. Some public water systems will also include where to find alternate water sources for affected customers until the contaminant is back to safe levels.

Water Main Breaks: This public notification is an urgent alert notifying affected customers that they may experience low pressure or no water because of the break. The alert will often come with a warning about related water quality issues as well as an approximate time of completion for the repairs. These repairs can frequently be extensive and may take several hours to days or longer to fix the problem.

Fire Hydrant Flushing: A non-urgent public notification alerting customers that a nearby fire hydrant will be getting flushed out. Flushing is a process that typically occurs once a year, which cleans out any mineral deposits and sediment and ensures that the hydrants are functioning properly. The alert also usually mentions that customers may notice a drop in pressure during the flushing period and that water may become cloudy temporarily from stirring up sediment. Customers are encouraged to run their water for a few minutes to let the water clear.

Consumer Confidence Reports

In addition to these required public notifications, water systems send out an annual statement to all customers within their service area called a consumer confidence report (CCR). The EPA mandates that every community water supplier send their customers these drinking water quality reports by mail or online. Renters should consult their landlord or leasing agency to receive copies of these reports.

CCRs can vary depending on the type of geology or natural contaminants in your area. In addition, not all contaminants pose problems to human or environmental health. Most public water systems will report on chlorine and chloramine since these are very common chemicals used to protect against harmful bacteria. However, they are considered “contaminants” as they do not naturally exist in the water and can pose health risks at high levels.

The CCR will list the violations, how they affect health, and how the water system plans to fix the issue(s). When referencing a CCR, it is essential to consider which contaminants are marked as "violated" and which are harmful to the environment or health. Any contaminants listed as "violated" have exceeded the level considered safe by the EPA, and action is required to lower them.

CCRs typically have four main components/sections. The first section provides an introduction and information about the source(s) of water gathered for treatment and covers precautions customers may need to take. The second section focuses on the water assessment results conducted throughout the year, including any contaminations found. If any violations occurred, this is the section where you can find additional information about them and the threats they might pose. The next component of the report is reserved for information about lead, nitrate, and arsenic levels. The EPA requires a statement on lead for all reports, but a statement on nitrate and arsenic is only needed if the contaminants exceed the limit. This section also includes the water quality data table that contains detailed data about each contaminant, including the amount detected. The last component of a CCR provides information on action levels, violations, and exceedances. All violations must be explained by including the length of time of the violation, any potential health effects, and the water system plans to fix the problem.