Jeff, where is that heater located? It looks like it is not in the house and may not be required to have a pan. If there is no requirement for a pan, then the drain requirement would be superfluous.
P2801.5 Required pan.
Where water heaters or hot water storage tanks are installed in locations where leakage of the tanks or connections will cause damage, the tank or water heater shall be installed in a galvanized steel pan having a minimum thickness of 24 gage (0.016 inch) (0.4 mm) or other pans for such use. Listed pans shall comply with CSA LC3.
Now, I always call out a w/h in a garage for upgrade with a pan and drain (especially if the stand is attached to the house wall), but I don't think the AHJ could require it. Nice thing about not being tied to the limits of the code, we can recommend based on common sense. Since most people store at least some items likely to be damaged by water in their garage, it just makes sense to have a drain pan and proper drain, even if the code does not require it.
Jim