Annual Water Disinfecting Change

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Annually in the month of March and in accordance with state and federal recommendations, the Cary/Apex Water Treatment Facility temporarily stops adding ammonia to its water treatment disinfection process. The Town uses chlorine as a disinfectant in its water treatment process but began adding ammonia to the process in 1993 to help reduce the amount of trihalomethanes, a byproduct formed when water is disinfected with chlorine. The State of North Carolina encourages all water systems that add ammonia to cleanse their system annually by switching to chlorine only and flushing the system. Town crews flush the entire water distribution system as part of this process.

The Town conducts this annual process in conjunction with other communities in the area. The water plant resumes adding ammonia to the water treatment process on April 1. Customers who use water for kidney dialysis machines, fish aquariums or other chlorine sensitive uses should be aware that water may contain chlorine, ammonia, or a mixture of the two at the beginning and end of March.

Some may notice a chlorine odor during this time; however, the water remains safe throughout this process. Customers are encouraged to check their water before washing white clothes and if the water appears discolored, all household faucets should run for a few minutes. Customers who have questions or who have water that fails to clear should call the Town of Cary at (919) 469-4090.

The Cary/Apex Water Treatment Facility provides treated water to Cary, Apex, Morrisville, the Raleigh-Durham International Airport and the Wake County portion of Research Triangle Park.


Town of Cary
(919) 469-4090