Hydrant Flushing/Treatment Change

Each Spring the City of Manassas conducts its hydrant flushing program. We do this is to maintain the high quality of water in our distribution system. You will likely see City of Manassas personnel in your neighborhoods starting on April 1, 2024 and continuing through early May. You will be able to identify City of Manassas personnel in several ways:

  1.  City of Manassas vehicles displaying the City of Manassas Water & Sewer Logo.
  2. City of Manassas staff will be wearing uniforms with the Manassas logo.

You may experience temporary discoloration or sediment in your water and recommend delaying laundry washing until crews are clear of the area. These conditions are not harmful and should subside quickly. If they do not subside, you should run cold water in your house for 1-2 minutes to get rid of any discoloration. If this problem persists please call our office at 703-257-8380.

During this time, our treatment process along with surrounding jurisdictions switches from using combined chlorine to free chlorine to facilitate an effective flushing program.

1. What are chloramines?
Chloramines are compounds made by combining chlorine and ammonia. Chloramines are a disinfectant used in drinking water to remove bacteria and viruses.

2. What is free chlorine?
Free chlorine is a disinfectant used in drinking water to remove bacteria and viruses.

3. When will the chlorine conversion occur?
During the spring flushing period.

4. Why do you convert from chloramines to free chlorine each spring?
Chloramines are a better long-term choice because they produce lower levels of disinfectant by-products like trihalomethane and haloacetic acid, which are possible carcinogens formed when chlorine mixes with natural organic substances or matter in water. Chloramines are more stable than chlorine and remain in the distribution system for a longer period of time. Free chlorine is a more aggressive disinfectant, and this temporary change in the water treatment process prevents bacteria from developing resistances to the usual disinfection treatment process.

5. Is water disinfected with free chlorine or chloramines safe?
Providing safe drinking water for the citizen and visitors to Manassas is our number one priority. Both free chlorine and chloramines are safe and effective. The Virginia Department of Health publishes guidelines on minimum and maximum concentrations for disinfectants in drinking water. The City of Manassas maintains the water it distributes with those guidelines. The water provided by the city is safe for people and animals to drink, for cooking and bathing, for watering the garden, and for all other common uses. However, precautions must be taken to remove or neutralize chloramines and free chlorine during the kidney dialysis process, in the preparation of water for fish tanks and ponds, and for businesses requiring highly-processed water. Any procedure optimized for the removal of chloramines will equally remove free chlorine.

6. Why are free chlorine and chloramines harmful to dialysis patients? Both free chlorine and chloramines may harm kidney dialysis patients during the dialysis process. The VDH can inspect and certify that dialysis facilities are prepared prior to the conversion from chloramines to free chlorine.

7. Will my tap water taste different when free chlorine is used in the water treatment process? Some customers may notice a slight chemical smell similar to that of water in a swimming pool. Each individual has his or her own sensitivity level to the taste and/or odor of free chlorine. Many detect no difference.

10. Will pool owners need to treat water differently? Pool owners must maintain the same chlorine level in water treated with either free chlorine or chloramines to prevent algal and bacterial growth. Pool supply stores can provide more information.

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