21 within the membrane vessel 20 at any time that the storage container 12 is full although it is critical to the present invention to orient the membrane vessel as shown in the figures in the container subspace 41 in order to produce sufficient back pressure across the r o membrane 21 for cleaning excessive head pressure must be avoided to this end the implementing engineer is cautioned to maintain the back pressure at or below 5 psi in order to prevent delaminating of the r o membrane 21 as previously mentioned a four way union 45 is provided in the fluid connection between the r o filter assembly 19 and the combination filtered water inlet and clean water outlet 13 interfacing with the storage container 12 in this manner the single opening to the storage container 12 may be utilized for filling of the storage container 12 as well as dispensing of the clean water therefrom to this end one connection from the four way union 45 is placed in fluid communication with an inlet 49 of a transfer pump 48 the outlet 50 from the transfer pump 48 is then connected to a pump clean water outlet 46 in the preferred embodiment of the present invention the transfer pump 48 comprises a pressure switch operated intermittent duty cycle self priming positive displacement pump such a pump is commercially available from the shurflo pump mfg co of santa anna calif under their model number 402.