The Waterra Pump system produces excellent well development, surging and clean out results because of the combination of simultaneous pumping and gentle well surging. Fines drawn into the well or “stirred up” will be pumped out. A Surge Block which is a plastic ring or doughnut that fits over certain Waterra Foot Valves, increases its diameter. This greatly reduces the annular gap between the well screen and the Foot Valve – Surge Block combo thereby enhancing the surging effect.