Mould is the result of a moisture problem that has gone undetected. Eliminating the source of the moisture is the first step in the correction process. Proper removal (remediating), of the mould is imperative to ensure against cross-contamination and the spread of mould to other parts of your property. How can you tell if it is mould? Discoloration Discoloration is a sign of mould. However, all discoloration is not due to mould. Carpeting near baseboards, for example, can be stained by outdoor pollution entering the home. Stains or soot may also be caused by the smoke from burning candles or cigarettes. Mould may be any colour: black, white, red, orange, yellow, blue or violet. Dab a drop of household bleach onto a suspected spot. If the stain loses its colour or disappears, it may be mould. If there is no change, it probably isn't mould. Smell/Odour Sometimes moulds are hidden and cannot be seen. A musty or earthy smell often indicates the presence of moulds. But a smell may not be present for all moulds. Even when you don't notice a smell, wet spots, dampness or evidence of a water leak are indications of moisture problems and mould may follow.