Thank u cvg. You are right it is potable water, but what i want to know is where to place my level guage, I'm not sure but I think it is better to locate it at the outlet connected by tee, the one that say 'vent pipe with cowl' might not be for air vent as there indicated 'DN 150 uPVC' for air vent on the reservoir, hooper might be for lifting chlorine bags as the dis-infection building is above the reservoir; I agree with the bell mouth but it is mentioned in the agreement