short of combustion air?

This mid E and gas water heater are in the same room, about 8x10. Has a door which can be closed. Granted the room is not sealed air tight with poly or the like. In your opinion(s) could this setup be lacking for combustion air? I had an instructor who said he always recommends a combustion air intake from the outside for fuel burning appliances. even if you don’t agree with ‘always’ would there be a lack in this room?
your input rocks!
mike in MN

“Utility room may not have enough combustion air for both the furnace and water heater. Recommend a qualified technician evaluate the room and repair if necessary.”

That’s what I’ve done in the past.

The pic just looks like a big closet and yes I would recommend combustion air be added. I don’t recommend anyone evaluate anything unless its foundation problems. If it needs combustion air just say so don’t beat around the bush it either does or it don’t.

In okla the attics are considered as outside air mayhap not in your area you would need to know the requirement for your state