Emergency Dispatch: (703) 335-7990

Customer Service: (703) 335-7950


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Water Distribution System Annual Flushing Program FAQ

Click on a topic below to view the answers.

What are chloramines?

Chloramines are a disinfectant used in drinking water to remove bacteria and viruses.

What is free chlorine?

Free chlorine is a slightly stronger disinfectant than chloramines, which may be used to remove slightly more resistant bacteria and viruses that may be found in the water distribution system.

Why do you convert from chloramine to free chlorine each spring?

The water that the Service Authority purchases from Fairfax Water and City of Manassas is disinfected with chloramines for most of the year. Using chloramines is a better long-term option because they produce lower levels of disinfection by-products, which are possible carcinogens that can form 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. However, free chlorine is a more aggressive disinfectant, and this temporary change in the water treatment process denies bacteria the ability to form resistances to the usual disinfection treatment process.

How long will free chlorine be used in the water system this year?

About three months (March 25, 2019-June 24, 2019).

Will my water taste different during the temporary conversion to free chlorine?

The use of free chlorine may result in a bit of a chemical odor in your water or smell slightly like water in a swimming pool. Each individual customer has his or her own sensitivity level to the taste and/or odor of free chlorine, though many detect no change at all.

Is free chlorine and chloraminated water safe?

Yes. Applied appropriately, both free chlorine and chloramines are safe and effective disinfectants. We are in regular communication with the Virginia Department of Health and strictly follow their guidelines on minimum and maximum chlorine levels.
Both forms of chlorinated water are safe for people and animals to drink, for cooking and bathing, 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. A de-chlorination procedure optimized for the removal of chloramines will equally remove free chlorine.

Why are free chlorine and chloramines harmful for dialysis patients?

Both free chlorine and chloramines may harm kidney dialysis patients during the dialysis process if it is not removed from water before passing into the bloodstream. The Virginia Department of Health can inspect and certify that dialysis facilities in the service area are prepared prior to the conversion to free chlorine and back to chloramines.
Like everyone else, dialysis patients may drink water treated with either free chlorine or chloramines because the digestive process neutralizes these chemicals before they can enter the bloodstream.

Will chloramines affect household plumbing, pipes and/or water heaters?

Some older household plumbing and water heaters may incorporate rubber materials and parts, which can degrade over time. Ask for chloramines-resistant parts, which are readily available at hardware supply stores or from your plumber, when replacing rubber plumbing materials. Chloramines-resistant parts will be effective regardless of the type of chlorine used.

How can I remove the chlorine taste from my water?

The taste of chlorine can be removed by boiling water, adding a bit of lemon juice, or filling a container with water and leaving it open to vent.

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 algae and bacterial growth. Pool supply stores can provide pool owners with more information.

What does “hydrant flushing” mean?

The Service Authority will forcefully draw the chlorinated water through fire hydrants for several weeks. The flushing also allows sediments/minerals that have collected in the water mains to be washed out. Additionally, the flushing process is part of the Service Authority’s hydrant preventive maintenance program.

Will I see a drop in water pressure due to the flushing?

Most customers will not see a drop in water pressure. If a change in pressure does occur, it usually lasts for only 30 minutes or less.

Will hydrant flushing in my area cause cloudiness or sediment in my water?

The flushing process can stir up sediments and minerals in water mains, occasionally resulting in some short-term cloudy water conditions. If you encounter such conditions, please flush the water from tap until the cloudiness dissipates.

If you experience this condition for an extended period of time, please contact the Service Authority’s Customer Service Department at (703) 335-7950 or by email at customerservice@pwcsa.org.

Where can I get more information?

For more information, please contact Regulatory Affairs Officer John DeRosa at (703) 335-7976 or email water_quality@pwcsa.org.