Emerging Contaminants

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Regulatory Standards for Water Quality

Partnership for Safe Water LogoCary's drinking water is safe. The Town of Cary maintains full compliance with all established drinking water regulatory standards and has an exceptional record of compliance since the Cary/Apex Water Treatment Facility began operating in 1993. 

The Safe Drinking Water Act (SDWA) is a federal law that protects public drinking water supplies throughout the nation. Under the SDWA, the Environmental Protection Agency sets standards for drinking water quality and provides the regulatory framework to ensure that our drinking water is safe. State agencies such as the North Carolina Department of Environmental Quality - Public Water Supply work in partnership with the EPA and municipal water providers to enforce the regulations and ensure the compliance of water systems throughout the state.

The Town routinely works to provide enhancements and improvements to our operating programs. One example of this dedicated approach is our ongoing work to support the Partnership for Safe Water. The Cary/Apex Water Treatment Facility (CAWTF) was named a Director’s Award facility by the Partnership for Safe Water for the 14th consecutive year. The Partnership for Safe Water is a national volunteer initiative developed by the EPA and national drinking water organizations to improve the quality of water delivered to customers by optimizing water system operations. More than 250 water utilities throughout the country are members; the CAWTF is a charter member. 

Emerging Contaminants

Unregulated synthetic or naturally-occurring chemicals that are not commonly monitored by water utilities are termed "contaminants of emerging concern" (CECs). More than 85,000 chemicals are registered in the United States and new chemicals and microorganisms continue to be identified. Some of these contaminants can be detected at extremely low levels in the environment by continuously improving laboratory and analytical methods. The health significance of these trace contaminants is often under review and the subject of further study and research.  

An example category of a contaminant of emerging concern is perfluorinated chemicals (PFCs). While two of these chemicals, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), have been detected in Cary's water, the amounts are below the health advisory levels that have been established by the EPA.

The fact that a substance is detectable doesn’t immediately mean that a substance is harmful to humans. For CECs of immediate concern, the EPA will issue a health advisory, which is based on the best available peer-reviewed studies about the health effects of the unregulated chemical. Health advisories provide information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. The EPA's health advisories are non-enforceable and non-regulatory and provide technical information to states agencies and other public health officials on health effects, analytical methodologies, and treatment technologies associated with drinking water.

The Town of Cary is working to stay ahead of the science as these substances continue to be measured at ever smaller concentrations. With modern laboratory methods, these substances can now be measured down to parts per trillion concentrations. For comparison, one part per trillion is approximately the equivalent of one drop of water in ten million gallons. The Town reports the formal results of regulatory testing and unregulated contaminant monitoring in its annual Consumer Confidence Report, which provides an annual summary of water system operations and water quality management throughout the water system.  

Lab Reports

Archived CEC Lab Reports can be found here



Call  311 or (919) 469-4000 outside Cary limits.

For questions about EPA health advisories, call the EPA’s Safe Drinking Water Hotline toll free at 1-800-426-4791 to speak with an information specialist during normal hours of operation. Bilingual service, including recorded messages, is available 24 hours per day, seven days per week, in English and Spanish.