A jockey pump is normally a smaller pump that fits into a lift station to handle nuisance flow or, possibly, small constant flows. Lift stations are designed to meet the peak flow that the system could see, but this can lead to a system that is way over-designed for the flow seen 99% of the time. For example, a lift station could be designed to handle all the stormwater from a housing development during a huge winter rainstorm, but for 10 months of the year the lift station only deals with runoff from sprinklers. It would be a waste to have a large pump constantly turning on and off to deal with a minimal amount of runoff, so the jockey pump takes care of these situations. This setup saves money through energy savings and maintenance costs.