Why do urinals smell?
Biofilm – the key problem is biofilm, a translucent film 0.1 mm thick derived from body fluids. It forms on the ceramic bowl and all pipe-work, but is particularly difficult to clean where it collects on the internal surface of the urinal waste outlet and trap above the water level. The biofilm takes several weeks to form – that s why water efficient urinals, or new urinals, often operate without odour problems for several months. The naturally occurring bacteria which thrive on this biofilm are what cause the smell. Even bleach is not successful at killing them. Reduction in water, for example using water misers, usually leads to an increase in build up. Leaking, staining and splashing – washers in urinal traps perish very quickly, causing leakage and staining outside of the trap – leading to bad smells. Odour also comes from urine that splashes on the walls and floor. When urine is left to dry it acts as a breeding ground for bad bacteria that cause unpleasant odours.
