About 100,000 Prince George’s County residents were advised Tuesday night to boil water before using it, after a break was found in a water main in the Bladensburg and Hyattsville area.

In what it called a “precautionary” measure, the Washington Suburban Sanitary Commission told those in areas around the break to bring water to a rolling boil for one minute and then to cool it before consuming it. This includes washing dishes by hand and brushing teeth, as well as making ice and preparing food. Also covered: water for pets.

The advisory was intended for areas including Hyattsville, Bladensburg, Mount Rainier, Cheverly, Chillum, Edmonston, Landover Hills, Glen Arden, Fairmount Heights, Seat Pleasant and Brentwood.

The area is bounded roughly by the East-West Highway on the north, Eastern Avenue on the west and the Capital Beltway on the east. The southern boundary includes parts of Central Avenue and Sheriff Road.

Crews were working Tuesday night to isolate the broken section of the 59-year-old main, which is two feet in diameter. The break occurred near Tanglewood Drive and Alternate Route 1.

Loss of pressure in a main increases the risk that contaminants may enter.

As of Tuesday night, no evidence of contamination had been found, WSSC said. To ensure safety, however, water testing is required after a main has broken.

WSSC said the advisory would remain in effect for about 48 hours.