The use of rainwater is done in the simplest way with a self-priming rainwater pump that is installed indoors. Rainwater pumps suck rainwater from the rain citern and pump it to the desired drain points. The GEP inner pumps are available in different capacities. The self-priming rainwater pumps must always be used in combination with a non-return valve in the suction line, preferably with a floating suction type of GEP.