Basic Concepts in Water Rights

Revised: February 11, 2010

Water Right Priority
"First in time, first in right"

The fundamental principal of Utah water law is priority between appropriators. Priority is established based on the date an appropriator placed the water to beneficial use if the right is claimed based on use that pre-exists the statutory process or the date application for appropriation was filed with the state engineer under the current statutory process. Priority distribution requires that a senior appropriator receive his full supply before a subsequent appropriator receives any water (Utah Code 73-3-21). Appropriators with the same priority share proportionately in the supply based on the definition of their individual rights.

An appropriator is considered to be receiving their full supply when they are either receiving all water entitled under the definition of the right or they make no additional call for diversion. In other words if an appropriator chooses not to divert their water right is considered to be satisfied. An appropriator is not authorized by law to dictate the next right in priority. A water right extends only to controlling one's own diversion and use of water. If a senior right is satisfied, the opportunity falls to the next water right in priority.

A junior appropriator is not required to reduce their diversion if the result would not increase the diversion of a prior appropriator who is not receiving their full supply. In other words a call to reduce junior priority diversions which will not result in an increase of the diversion of the senior appropriator is a futile call and not required. This is the rule under which non-consumptive uses may divert water out of priority. If curtailing the diversion does not result in the increase in diversion of a senior appropriator it does not accomplish the purposes of the prior appropriation doctrine and is not required. The determination that a futile call situation exists is made by the State Engineer.

Utah does not recognize de minimis use. In other words a junior appropriator may not use the argument that their diversion has a minimal or negligible effect on a senior appropriator to avoid curtailment if the senior right is not satisfied. No matter how small the effect if there is a cause and effect relationship the junior right must yield to the senior appropriator.