A covering system that covers an end pipe of a chimney system. A portion of the end pipe protrudes from the roof of a house or building where the chimney system is located. The system comprises of at least two base supports that sit on the roof. A channel spanning around the end pipe of the chimney system that protrudes from the roof. The base supports are attached at the base of the channel. The base has a protruding section whose dimensions are larger than the channel. A collar covering having a first and a second opening. The collar covers the protruding section of the base by its first opening and receives the channel at its second opening. A crown top base that slides inside of the channel from the top.

A water heater heats water with a combustion gas. An exhaust tube includes one end portion and the other end portion, is connected to the water heater at one end portion, and inside thereof is defined as an emission path for the combustion gas. An exhaust pipe is greater in outer diameter than the exhaust tube, and a part of the exhaust tube on a side of the other end portion is introduced in the inside thereof. An exhaust terminal is attached to an end portion of the exhaust pipe and has an exhaust port for exhausting the combustion gas to the outside. An exhaust straightening member is attached to the other end portion of the exhaust tube and has an opening portion for allowing the combustion gas to flow out toward the exhaust port.