Generally speaking, cannabis plant material is sold by weight. A measure of the plant materials quality can be determined in many different ways, one of which is by the amount of moisture it contains. The amount of moisture in a cannabis sample refers to the percentage of the sample's total weight that is made up of water.

Moisture content is crucial as an indicator of the potential activity of microbiological contaminants such as bacteria and fungi. If moisture content of a sample is above 15%, it could indicate a high risk for such contamination.