A pumping device for liquids is described which comprises a tank for liquids, from which a feeding pipe of a pump with a solar panel draws. The tank consists of a supporting frame with tubular uprights and upper and lower horizontal connection lengths, which supports and surrounds a flexible bag for containing liquids and has an upper connection crossbar of the upper horizontal lengths of the supporting frame, on which the pump with solar panel is mounted. The bag has a lower filling hole or mouth, in which the feeding pipe can be inserted and an overflow hole made in the upper of part of its side wall in position lower than said mouth.