Vents installed into the chimney can pose a deadly scenario if they are not properly installed. Our inspector found deadly gases leaking back into the house during the inspection of the water heater vent. This is the number one reason people die each year from carbon monoxide poisonings. The vent should be installed into the chimney and ran to the top of the chimney flue and sealed with the proper size vent cap. Another option, and a safer one would be to install a power vent on top of the water heater and vent the gases out the side of the foundation wall.