A submersible water pump and a dewatering system comprising the submersible pump. The submersible water pump includes a housing and an outer tube. The housing includes a housing dividing wall and a cylinder head having a bore therethrough through which the outer tube fits. The housing is in slidable engagement with the outer tube and the housing dividing wall. The dewatering system with the submersible pump is used to pump water from vertical coal bed methane wells.