The D.C. Water and Sewer Authority (WASA) is conducting its annual program to flush water mains throughout the city, a procedure designed to remove sediments and improve drinking water quality.

From 10 p.m. to 6:30 a.m. Sunday through Thursday, WASA crews are opening fire hydrants in designated neighborhoods and flushing water.

The water supply to customers is not shut off during the flushing.

Customers might notice some water discoloration early in the morning. If that happens, WASA recommends that residents open the cold water tap and allow the water to flow slowly until it is clear.

Customers should not run hot water or do laundry during the flushing. If the hot water becomes discolored, WASA recommends flushing the hot water tank by opening the valve at the bottom of the tank.

The flushing program will continue through November.

These neighborhoods, with boundary streets, are scheduled for flushing the week beginning Aug. 8:

* ANC 6A (work area bounded by East Capitol Street, 19th Street SE, E Street SE and 17th Street SE).

* ANC 4C (work area in Northwest, bounded by Longfellow Street, New Hampshire Avenue, Farragut Street and Fifth Street).

* ANC 2B (in Northwest, bounded by Florida Avenue, 19th Street, P Street and 23rd Street).

* ANC 5B (in Northwest, bounded by Sheridan Street, Georgia Avenue, Missouri Avenue and 16th Street).

For information, call the WASA Water Quality Office, 202-612-3440, 8 a.m.- 4 p.m. In an emergency, call WASA's 24-hour hotline, 202-612-3400.