One on the ceiling above the water heater.
Water heater vent pipe through roof.
Direct vent water heaters.
Hello jody if it is a natural vent type water heater you can not vent it through the side wall it has to vent above the roof.
Exhaust gases are vented outdoors through a separate vent duct or through a separate chamber of the same pipe this requires a double wall vent duct.
As when the gas water heater vent pipe installation is going on gas water heater venting options is good and safe.
And for better results one can install a water heater roof vent.
A water heater vent pipe can be used for this venting with a hot water heater vent cap for safety reasons.
With a direct vent system air for combustion is drawn from a vent pipe that runs through an exterior wall or the roof.
In order to do this two critical measurements must be taken.
Other issue is the bathroom installation which isn t permitted as well unless the water heater closet is sealed from the bathroom area air tight doors and it has a separate fresh air supply from exterior or other areas of the house that can be used for this purpose.
Illustrations of proper gas fired water heater venting using type b double wall vent pipe through a roof above or through a chimney below include details for the flue vent connector such as the requirement of a minimum vent connector upwards slope of 1 4 per foot of horizontal run.