Bryan's water services crew started smoke testing of the city's sewer lines Thursday morning.
They pumped smoke into the lines in search of breaks and defects.
City officials say smoke exits vent pipes on roofs, out of manholes and from the ground if there are breaks, but that the smoke is non-toxic and doesn't leave a residue.
Citizens do not need to be home during the test.
Intermittent testing could be done into October.
The following are the target areas for the city:
1600 through 2600 Block of North Texas Avenue
600 through 1700 Block of San Jacinto Lane
600 through 700 Block of Dean Street, Jones Street
West Pruitt Street, 1200 through 1400 Block of West Martin Luther King Street
1100 through 1800 Block of West 18th Street
900 through 1700 Block of West 17th Street
600 through 1000 Block of West 16th Street
1100 through 1200 Block of Hall Street
500 through 600 Block of West 15th Street
500 Block of West 14th Street
1300 through 1600 Block of North Sims Avenue
Live Oak Street
White Oak Street
Red Oak Street
Water Oak Street
Pin Oak Street