Abstract: A water purification device has first and second like hollow elongated members adapted for detachable engagement with each other, and when engaged defining an elongated housing having a cylindrically shaped central section and opposite ends with small openings. A cylindrically shaped filter is disposed removably in said central section. The filter ends are disposed transversely to an axial bore in the filter. A first mechanism detachably securable to a water faucet pivotably secures one housing end to the faucet and conducts water from the port into the housing. A thin flat annularly shaped disposable fiber prefilter removably overlies the end of the filter adjacent said one housing end. A second mechanism connected between said first mechanism and the bore has a first position at which the conducted water flows through the device unfiltered and has a second position at which the water is filtered.