To identify mold, visibly accessible wall and ceiling surfaces (rooms and closets), floors, window trims, mouldings, and built-in cabinetry should be visibly inspected for signs of discoloration, paint damage, or surface irregularity suggesting water damage or mold growth.



Special attention should be focused on surfaces that are more susceptible to water damage including perimeter (window) walls, kitchen and bathroom walls that contain plumbing pipes and fixtures (aka “wet” walls), pipe chases, the walls of closets and rooms that adjoin bathtub/shower enclosures, walls behind radiators, walls behind base mouldings, bathroom walls and ceilings, bathroom vanities, cabinets beneath kitchen sinks, and basement walls and ceilings.

Most frequently, the discoloration associated with mold growth is blackish, brownish, or greenish, and the spots of discoloration are somewhat circular and of various sizes which may coalesce into solid mats. Yellowish, goldish, or rust colored jagged-edged areas of discoloration are frequently only water stains, and may not be an indication of mold. The powdery whitish precipitate that often forms on and around cracked and blistered paint on painted plaster surfaces (sometimes called effervescence) is wrongly considered by many building superintendents to consist only of mineral deposits. To the contrary, these precipitates are very likely to contain high levels of fungal and/or bacterial growth.