Where does Nevada's water come from?

John Cobourn

In early June 2015, Reno’s KNRV News Channel 4 aired a story which quoted me as saying that storing rain water from home downspouts in barrels for later use on the landscape is illegal in Nevada. This is true, though this is rarely enforced. In the next few days, over 60 people commented online about the ”ridiculous” nature of this story. The strong reaction made me realize that some Nevadans do not understand Nevada’s water supply nor the laws and regulations that govern it. In times of drought, this is an important topic to learn about.

Nevada’s water supply is the surface water available for use from streams, lakes and reservoirs plus 

Carson River floodplain from Kingsbury Grade

the groundwater from wells. It is replenished each year by variable amounts of precipitation, and it is depleted each year by evaporation, transpiration by plants, and consumptive (evaporative) uses by humans. In terms of climate, Nevada is the driest state in the nation.

In the current drought (see Livingwithdrought.com for more information, and the final report from the Nevada Drought Forum (available soon (December, 2015) at http://drought.nv.gov/), our surface water supplies are much lower than average due to decreased winter snowpack.  The groundwater in aquifers in many places is being used more rapidly than it is replenished by precipitation. In some agricultural regions, farmers are using more “supplemental water rights” from wells to grow thirsty crops like alfalfa—Nevada’s primary crop. In some valleys, the water tables are dropping.



The Carson River sustains agriculture, wildlife habitat and
rangeland along its course, from the Sierra Mountains
to the terminus in the Carson Sink. 

Water in Nevada is used as follows: About 80% of water is used for irrigated agriculture. Public supply for municipal and industrial use accounts for around 13% of water use and mining uses about 7%.

All surface and ground water in Nevada belong to the people of the State. Entities within the State can use that water if they own ”water rights” for use of a specific quantity of water in a particular place for a specific “beneficial use” such as irrigating a certain number of acres of alfalfa.

Residents cannot capture and store precipitation for later use unless they own a water right to put the water to beneficial use. Water law is based on the appropriation doctrine of “First in time—First in right.” In times of drought, senior rights owners can use all of their water before junior owners get to use any. Water law is described in Nevada Revised Statutes 533 and 534, and further defined by court cases and court decrees.

Water law and the water supply in Nevada are complicated. In future blogs, I will explain some of the facts in this article in more detail. It is a fascinating field of study that is part of Nevada’s rich frontier history.