Is ok for a gas water air vent to terminate in the attic.
Thanks
No … No
Looks to me like WH is vented via the B-Vent going through the roof (which has its own issues), and the rectangular duct is admitting in combustion air from the attic via the grills at the top and bottom of the wall behind the WH.
Joe, I believe the question was “can the combustion make up air source come from the attic?” and the question is yes. However the exhaust flue does have to discharge to the exterior.
Are those broken decking boards in the second pic?
Also, make sure those joints have screws in them to secure them…not just tape.
Modern B-vents are self-locking and should not have any screws. . .
that bottom connection in the second pic looked a little suspect. Just threw it out there just in case.
Only place you should have screws is at the draft hood to flue pipe connection. There should be 3 screws installed at this connection.
How do you guys feel about combustion air being drawn from attic with water heater located in closet and ceiling covering (sheetrock ceiling) above missing. Just hole in the ceiling above the water heater. I know the ceiling should be fireblocked, but I see this set up often in older construction.
Didnt mean to 
change the subject.
Duct Tape or Duck Tape, is not designed to be used on Ductwork. It is general use tap. In the 2nd photo the lower section looks like General Purpose Duct Tape… The upper connection looks like the proper type of foil tape. 
Off subject, what does everyone think about the use of the flex-lines used on the Hot & Cold water lines? I personally have not ever used them. I always add a 6" to 8" nipple to the top of the WH with a Di-elect union to CU. That way I have the available height for different size replacement WH. I also like to install valves on both hot & cold sides, that way I don’t have to deal with waiting for the pipes to drain.
My family has owned a lot of rental homes, I worked on the construction of 90% of them.
Standard operating proceedure in CA. . .
Jeff, I had a feeling someone from CA would be the first to reply. Standard due to Earth Quakes???
Would it be normal (or a good idea) to replace them each time the WH is replaced? (Flexable things tend to crack or break without notice). I know that they are made more durable but, would you replace them when replacing a WH?
Is that a dryer vent being used as a flue?
tom
Looks like flexible B vent to me.
Single wall and double wall, 1" clearance.
Copper flex, I would change out. Newer installations are typically steel-braided (as my own currently is). These last much longer. . .