Annual Water Treatment Process Change

The City of Sanford typically uses chloramine (a combination of ammonia and chlorine) to disinfect its drinking water. However, the N.C. Division of Water Resources requires all water treatment facilities to stop using ammonia for 30 days once per year to help maintain the highest quality of water.

Why the Change?

Without being bound to ammonia, chlorine will burn itself up before it can travel through the entire distribution system. Chloramine lasts longer because chlorine becomes less reactive when it is bound to ammonia.

Therefore, we use chloramine for 11 months of the year because it lasts longer in the system (doesn’t burn itself up) and is very efficient at eliminating organisms. Because it is so reactive, chlorine is used for 1 month to provide the strongest level of disinfectant and clean out any buildup in the lines, but only for a limited period of time.

This process of maintaining and cleaning the water lines is something water filtration facilities do annually to care for the lines and ensure that they can continue providing high quality water.

Date of Change

Each year, the City stops adding ammonia to the municipal water supply on March 1 and resumes adding ammonia to the disinfection process on April 1. Additionally, we will flush the water mains throughout our system during this time to remove sediment in the water lines and refresh the entire distribution system.

What to Expect

During the changes in our disinfection process and flushing of the system, you may notice a chlorine odor and/or discoloration to your water. Your water, however, will still be safe for drinking, bathing, and other daily uses.

While there are no associated health risks with the odor or discoloration, you may want to limit certain activities (such as washing clothes) during this time.

If you notice discoloration at the tap, allowing the water to run for 5 to 10 minutes should clear up the problem. Also, if you have aquatic pets, you may want to consult your local pet store to ask how this may affect your pet’s habitat.

Why flush the water lines during the process change?

Flushing the mains involves opening water hydrants and letting them flush into ditches. By flushing the mains, we are able to quickly reduce the amount of chloraminated water in the system to make room for water with free chlorine.


Contact the Water Filtration Facility at 919-777-1803. The facility is staffed around the clock.