Indeed. The first thing that would happen if water were a lot more scarce is that lots of things would become more expensive, since water is an input to just about everything. Presumably people would change their behaviour in lots of ways short of just up and killing each other. "OMG expensive meat!" is a lot more likely than "OMG war!"

Maybe a biased source, but http://www.ecotechwater.com/Company/watertrivia.html:

How much water does it take to produce one ton of steel? 62,600 gallons

How much water must a dairy cow drink to produce one gallon of milk? 4 gallons

How much water is used during the growing/production of a chicken? 400 gallons

How much water is used during the growing/production of almonds? 12 gallons

How much water is used during the growing/production of french fries? 6 gallons

How much water is used during the growing/production of a single orange? 13.8 gallons

How much water is used during the growing/production of a watermelon? 100 gallons

How much water is used during the growing/production of a loaf of bread? 150 gallons

How much water is used during the growing/production of a tomato? 3 gallons

How much water is used during the growing/production of rice? 35 gallons

How much water us used during the production of an egg? 120 gallons

How much water does it take to process a quarter pound of hamburger? Approximately one gallon.

How much water does it take to make four new tires? 2,072 gallons.