Drinking water violations across Connecticut

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The number of violations related to water quality in public drinking water systems has decreased since 2005 in Connecticut.

Trend CT previously looked at where elevated levels of lead have been detected, but those cases represent only 0.2 percent of all water-quality violations in the state.

Nearly 55,000 water quality violations have been tracked by the U.S. Environmental Protection Agency in Connecticut since 2000.

A violation by a drinking-water system means it was out of compliance with an environmental requirement from the Clean Air Act, Clean Water Act or Safe Drinking Water Act. Violations include the presence of excessive pollutants, improper hazardous waste handling, or a failure to submit a required report.

Depending on the statute, violations are either self-reported or found through state inspections.

The agency sets the legal limits on more than 90 contaminants in drinking water. Some contaminants are not regulated by the Safe Drinking Water Act, but the agency still collects data for future review.

The most-cited contaminants are listed as “not regulated” – chemicals that are present in drinking water but do not fall under a specific rule or health-based standards set under the Safe Drinking Water Act. Those contaminants include chemicals like organic solvents bromobenzene and naphthalene.

Other oft-cited rules limit the presence of coliform bacteria or volatile organic chemicals.

The term “total coliform” refers to a group of closely related bacteria that are generally harmless. They are natural and common inhabitants of the soil and ambient waters (such as lakes and rivers). But their presence is a warning sign that water may be vulnerable to fecal contamination and pathogens could be present.

Visit the EPA’s website for descriptions of the other drinking water requirements and contaminants.

There are nearly 2,500 public drinking water systems in Connecticut. The state’s Department of Health reports violations to the EPA. Water regulations establish maximum contaminant levels, treatment techniques, and monitoring and reporting requirements to ensure that water systems provide safe water to their customers.

A public water system is defined as a system that provides water for human consumption and has at least 15 service connections or regularly serves at least 25 individuals at least 60 days out of the year. The EPA does not have the authority to regulate private drinking water wells that do not serve the public.

Violation information for each water system includes whether it has followed established monitoring and reporting schedules, complied with mandated treatment techniques, violated any Maximum Contaminant Levels (MCLs), or communicated vital information to their customers.

Enforcement information includes the actions primary enforcement agencies, like Connecticut’s Department of Health, have taken to ensure that drinking water systems return to compliance if they are in violation of a drinking water regulation.

There are several types of possible violations
  • Health-Based
    • Exceeding the maximum contaminant levels (MCLs) which specify the highest allowable contaminant concentrations in drinking water.
    • Exceeding the maximum residual disinfectant levels (MRDLs), which specify the highest concentrations of disinfectants allowed in drinking water.
    • Failing to follow treatment technique requirements, which specify certain processes intended to reduce the level of a contaminant.
  • Monitoring and Reporting – Failing to regularly monitor drinking water quality, or to submit monitoring results in a timely fashion to the state primary enforcement agency or EPA, as required by the Safe Drinking Water Act.
  • Public Notice – Failing to follow public notification requirements, which require systems to alert consumers if there is a serious problem with their drinking water or other violations of system requirements.
  • Other – Violating other legal requirements, such as failing to issue annual consumer confidence reports.


If a drinking water system does not resolve a violation after it has been identified, the Department of Health must initiate enforcement.

Some enforcement actions include reminder letters, warning letters, notices of violation, field visits, and phone calls.

In 2009, primacy agencies initiated 169,015 informal actions across the country.

If the violation continues, a schedule will be set to resolve it, which can be enforced by citations, administrative orders, penalties, or criminal charges.

If the risk to public health is great, the EPA and Department of Health can issue emergency orders that require a public water system to take immediate action to protect public health and return the system to compliance.

Three types of public water systems
  • Community – A water system that serves the same population throughout the year.
  • Non-Transient/Non-Community – A public water system that regularly supplies water to at least 25 of the same people at least six months per year. These can include facilities like schools, factories, office buildings, and hospitals which have their own water systems.
  • Transient/Non-Community – A public water system that provides water in a place such as a gas station or campground where people do not remain for a long time.

Check our work: The GitHub repository containing our work is available here. We encourage you to look over our calculations and expand upon our analysis.

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