The definition of a dip slide, as described in the HSE approved code of practice and guidance for the control of legionella bacteria in water systems, is a means of testing the microbial content of liquids. It consists of a plastic carrier bearing a sterile culture medium which can be dipped in the liquid to be sampled. It is then incubated to allow microbial growth. The resulting microbial colonies are estimated by reference to a chart.
Dipslides are the most common method of measuring and monitoring microbial activity within many systems and commonly cooling systems.