A tank fill assist for filling a tank or other equivalent volume from a remote source of liquid, for example filling a consumer product from a sink or bathroom faucet with fresh water. The fill assist is normally stowed within the interior of the tank. It is withdrawn for connection to a faucet for tank filling, and is then returned to stowed position after tank filling. The fill assist comprises standard flexible conduit with unique inlet and outlet fittings at opposite ends. The outlet fitting is disposed within the interior of the tank and is constructed and arranged to prevent accidental separation of the fill assist from the tank when the conduit is withdrawn from the tank yet to allow passage through the fill opening when it is intended to either join or separate the fill assist to or from the tank. The inlet fitting is of thermoplastic rubber and can be fitted over the outlets of typical sink and bathroom faucets. A retainer is disposed around the flexible conduit and is axially captured on the conduit between the inlet and outlet fittings. The retainer forms a recepticle within which the inlet fittings nest when the fill assist is stowed. The retainer in turn nests within the fill opening. The retainer comprises apertures in its sidewall which provide an alternate fill patch into the tank which is independent of the fill path through the conduit. The retainer seats on partial internal screw threads formed on the inner wall of the fill opening so that the usual closure cap which has locking tabs which engage the partial screw threads can be screwed onto and off the fill opening in the usual manner without interference from the stowed fill assist.