how long does it take to lose water weight?

I've been craving salt pretty badly for a couple of months now, but within the last week or so my weight just skyrocketed and I'm pretty sure it's because I've been eating a lot of salt with water (as in I'll sit down with air popped popcorn and just dump salt all over it and eat it with 1-2L or water). I wasn't really concerned with water weight before but now I'm thinking it's making me really bloated, how long can water weight take to lose? Bonus points if you can tell me what my kidneys are waiting for in terms of flushing out the water!