Abstract: A well-cleaning system (10) is provided with a control system (30) where waste liquid level sensors (35, 36) co-operate with timers (39, 40) to control the frequency and duration of the well-cleaning cycles. Chemicals can be injected into the water on demand from a well-conditioning sensor (38); and the well-cleaning system (10) can be operated when high H2S gas levels are detected in the well (20) by a H2S gas sensor (37).