Abstract: A process and device for collecting and maintaining fresh amounts of rainwater. The device is comprised of a storage vessel having an inlet passage terminating near the bottom of the vessel, which is further provided with an overflow and a drain. The device possesses a through-pipe which becomes positioned in line with sections of a downspout between which the device can be installed. Water is introduced into the vessel via an upper downspout section and a branch pipe and excess water above the vessel's capacity is discharged via an overflow passage directly into the through-pipe and a lower downspout section. The vessel and its parts are preferably made in one piece by blow-molding a plastic material. The device is substantially intended for collecting small amounts of water.