The photovoltaic water pumping systems (PV-WPS) is considered as one of the most promising areas in photovoltaic applications. The aim of this work is to determine the effect of pumping head on PV-WPS using the optimum PV-array configuration, adequate to supply a DC Helical pump with an optimum energy amount, under the outdoor conditions of Madinah site. Four different pumping head have been tested (50 m, 60 m, 70 m and 80 m). The tests have been carried for a different heads, under sunny day- light hours, in a real well at a farm in Madinah site. The best system efficiency has been obtained for the head of 80 m which is recommended for SQF submersible pump for a deep head. Also, the flow rate Q depends basically on two factors: the pumping head H and the global solar irradiation Hg. The model developed should be able to predict the flow rate Q for any head chosen with a best accuracy.