I follow a diet which is salt-free, and very low in sodium, so I don't get as thirsty as those who eat a higher sodium diet. Also, I eat tons of fruits and vegetables, so my food has a high water content. As a result, the only time I feel the need to drink any water at all is when I'm getting some vigorous exercise, and working up a sweat.
The only time my mouth ever gets dry is if I let someone talk me into eating out at a restaurant against my better judgement. Restaurant food always seems to have way too much sodium in it. Then my mouth gets dry, and I want to drink lots of water. Otherwise, as long as I'm eating the amount of sodium that is naturally found in whole foods that contain no added salt, I do not get thirsty.