Can One Roof Vent Serve a Water Heater? A roof replacement is a good time to rethink old plumbing and venting. One homeowner had a 13-year-old, 40-gallon gas water heater. The heater sat inside a small hallway closet. The closet measured about 27 inches by 23 inches. It also had a tight door with little… Continue reading Can One Roof Vent Serve a Water Heater?