Water-Rate Structure refers to the way that water is sold.  For single-family residences there is a tiered-structure that increases in blocks as more water is used. This usually means that the last increment of water used is more expensive than the average cost, giving an added incentive (commonly called the “conservation signal”) to reduce usage.

For commercial, industrial and use by NAU there are currently “flat rate” structures with different prices for each user category. The flat rate structure means that the cost is the same for all usage, from the first gallon and the last. It does not give an enhanced conservation signal like the tiered-structure does.