You will only be able to "slam" the capacity of your stomach. But the good news is that Water really flows through your stomach very quickly.
For example, right now I am 10 weeks post op & have a stomach capacity of about 4-5oz. Therefore I can quickly drink 4 oz of water, wait a few seconds and do another 4oz. & repeat.
I can drink a .5L(16.9oz) bottle of water in under a minute, not that I make a habit of this.
At 1year post-op my stomach capacity will be 10oz which will allow me to drink 1/2 of the same bottle, breath for a couple seconds then finish it.