A water saving device for us in a hot water system to recover an initial volume of cold water when a hot water tap is turned on. The device has an inlet for receiving water piped from a water heater, a primary outlet for delivering hot water to a tap, and a by-pass outlet through which any cooled water is diverted by a thermally actuated shuttle valve. The device also includes a secondary valve for closing off the by-pass outlet when the water pressure downstream of the primary outlet is high (such as when the down stream hot water delivery tap is closed and opening the by pass outlet when the water pressure downstream of the primary outlet is low, such as when the downstream hot water delivery tap is opened.