I did an inspection today and hope someone can help me out on this. It is a condo and has the water heater in a utility closet next to the Heating and Air conditioning unit. The heat is a hot water systme supplied by the water heater. Here is the problem. The closet door has both the upper and lower vents of more than likely the right size for a unit built in 1987 and the return air is directly below these vents. Here is the picture I hope.
It’s okay if the water heater is electric 
Forgot to mention, the water heater is a natural gas water heater.
Cannot, for some reason get a picture to post. My apologies.
Joseph you may have to resize the picture smaller for it to upload
Whatever your pictures shows, the return air intake must be 10 feet away from an open gas burner.