The City of Longueuil is warning some of its residents not to drink tap water for the time being without boiling it for one minute first.

The boil-water advisory went into effect Tuesday evening in Vieux-Longueuil between Lalande, Kirouac, Jean-Paul Vincent, Claude, Lafrance (Hwy 20 service road) and Marie-Victorin (Route 132) Sts.

The precaution is required as a result of laboratory test results that show the presence of E. coli in the water system.