silly question...
You'll probably only be able to sip some warm water or tea for the first couple of days anyways. As for the soup, I would make a small batch per the packet directions, and then just see how many ozs you can get in by sipping it.
I did have some warm tea the day after my surgery, but it was on my surgeon's list for clear liquids - along with coffee. You should ask your surgeon if you can have coffee and tea afterwards and see what he/she says. It could just be an oversight that it wasn't on your list, or they could have a good reason to omit it.
The hospital that I had my surgery at gave me these little 2oz medicine cups. They worked like a charm. I would fill one and toss it when I emptied it. If you are only using it for water you can reuse them, but it helped to keep track of what I was taking it. You should be able to pick them up at any medical supply place.
-Nikki-