Emergency Dispatch: (703) 335-7990

Customer Service: (703) 335-7950


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Water Distribution System Flushing Program FAQ

Click on a topic below to view the answers.

What does the term "system flushing" mean?

The Service Authority flushes water from fire hydrants connected to its distribution system each spring in order to forcefully draw water through its network of pipes. This process dislodges sediments and minerals that may have collected in water mains since the prior year’s system flush.

What are chloramines?

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

What is free chlorine?

Free chlorine is also used to disinfect drinking water, but it is a stronger disinfectant than chloramines.

Why is the water that the Service Authority distributes to customers disinfected with free chlorine instead of chloramines each spring?

Each spring, the Service Authority’s drinking water providers—Fairfax Water and the City of Manassas—temporarily change the primary disinfectant in their water treatment process from chloramines to free chlorine. Our water providers indicate that this temporary change facilitates an effective flushing program for the distribution system and is a drinking water industry best practice.

When will the system flushing program begin and end this year?

The Service Authority will flush the distribution system from approximately late March-May 2024.

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

The use of free chlorine may result in a slight chlorine odor in your tap water. 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.

What can I do to remove a chlorine smell from my tap water?

Fill a pitcher with water and leave it uncovered on your counter, which will allow the odor to dissipate within a couple of hours.

Can system 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 cloudiness. If you encounter this condition, please run cold water from your tap until the cloudiness dissipates. If your water looks cloudy for an extended period of time, please contact the Service Authority’s Customer Service Department at (703) 335-7950 or email customerservice@pwcsa.org.

Could I see a drop in water pressure due to hydrant flushing in my area?

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 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.

Could water disinfected with either free chlorine or chloramines be harmful to dialysis patients if it is used in the dialysis process?

Both free chlorine and chloramines may harm kidney dialysis patients during the dialysis process if they are not removed from water before it passes into the bloodstream. Because dialysis centers use special water treatment processes to prevent adverse impacts to patients during dialysis therapy, the Service Authority notifies all centers in its service area about the conversion to free chlorine each year prior to the change of disinfectant. Like everyone else, dialysis patients may drink water treated with either free chlorine or chloramines because the digestive process neutralizes these chemicals before they enter the bloodstream.

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.

Is water disinfected with either free chlorine or chloramines safe for my pet fish?

No. Precautions must be taken to remove or neutralize chloramines and free chlorine during the preparation of water for fish tanks and ponds.

How can I get more information about Service Authority water quality?

For more information, please contact the Service Authority’s Regulatory Affairs Office at (703) 331-4162 or email water_quality@pwcsa.org.