Half-margarita, half-tom collins, the ranch water is an eminently refreshing drink said to have originated in marfa, texas. The most important ingredient is the sparkling water. In marfa, youll find it made only with topo chico, an exceptionally effervescent mineral water made in mexico. You can use any good sparkling water you like, or even a flavored sparkling water (lime lacroix is a favorite of ours). The precise amount of syrup to use is a matter of personal preference. Some folks prefer theirs bone-dry, but we typically add a scant barspoon to ours.