[7] The larva is semiaquatic and lives in the gelatinous ooze associated with leaks of sewage effluent,[5] drains, and in trickling filter systems.

The wing muscles are relatively weak and the insects mostly run or hop, occasionally making short flights.

Both larvae and pupae are usually to be found in the top 2.5 cm (1 in) of the substrate, sometimes deeper than this when the material is fairly dry.

[6][7] A trickling filter system is a form of biological treatment widely used to process sewage.

In the medium live over 200 species of bacteria, algae, worms, protozoa, and insects including larvae of the drain fly; together these organisms form a biofilm which processes the fluid passing through the filter system and removes pollutants.