I do believe that water in its drinkable form does have periods of scarcity. However, for the grand picture of this topic, I think not. Cheap 'anything' is at risk. More is always purchased at a lower price, and when it comes to life's essentials, this concept will be more factual than ever. The consumer is not at fault for indulging in a good deal. The supplier did not use a rational approach in distribution.
Farmer's should have priority on water because its consumption redistributes goods back into the economy. They are using that water to grow food, they should get it at a less expensive rate than everyone else.
General consumers should not be wasting water. Although we aren't running out of water per se, the resources used to handle and treat the water to make it available for public use may be scarce, or expensive.