The smoke will not enter a home if the plumbing is in good condition and if drain traps contain some water. Outside, it is normal for smoke to be seen coming from roof vents, building foundations, manhole covers and yard cleanouts. Smoke coming from the vents on the roofs of homes indicates to the work crew that smoke has filled all sewers. Smoke will enter your home if the vents connected to your buildings’ sewer pipe are inadequate, defective or improperly installed, if the traps under sinks, tubs, basins, showers and other drains are dry, defective, improperly installed or missing, or if the pipes, connections and seals of the wastewater drain system in and under your building are damaged, defective, has plugs missing, or are improperly installed.