Abstract: An emergency potable water supply system including a generally cylindrical water tank seated on a base member, with the tank having opposite dome-shaped portions. An inlet and discharge fitting is received in an opening in the uppermost part of the upper dome shaped portion, and a drain fitting is received in the lowermost part of the inverted dome-shaped bottom portion. All external connection fittings are conventional garden hose fittings, with the inlet fitting adapted for coupling, via a hose, to a standard exterior residential faucet. A check valve is provided at the inlet fitting, to serve as an anti-siphon valve in the event of a pressure drop at the inlet, and to serve as a vacuum release for discharge of the contents of the tank when needed. A garden hose is coupled to the outlet fitting for continual replenishment of the supply of water during use of the garden hose for normal tasks such as watering plants and shrubs.