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What is a Water Right?

Fish Hatchery Creek, Point Reyes National Seashore, California
Fish Hatchery Creek, Point Reyes National Seashore, California (NPS, 2007).

A water right is a legal authorization for a party to divert and use water from a water source, such as a stream, pond, lake, or aquifer. In the United States, there are two basic doctrines for establishing and administering water rights: the riparian doctrine and the prior appropriation doctrine. The riparian doctrine was derived from English common law and is predominately used in the eastern United States. The prior appropriation doctrine was developed in California and Colorado and is predominately used in the western States. Each state has its own variation of the two basic principles, and some states use elements from both doctrines. An important type of water right for national park units is called a "federal reserved right." In general, water rights are administered by state agencies, and conflicts over water rights are determined by state agency hearings or state court proceedings.

Riparian Water Rights

Under the riparian doctrine, all landowners whose property adjoins a water source have the right to make reasonable use of water from that source. Reasonable use means that each riparian owner can take, use, and discharge surface water so long as that use does not excessively diminish the quality or quantity of the water that available to other riparian owners. In theory, water surpluses and shortages on a source are to be shared equally among all riparian-right holders. Water generally must be used on the riparian parcel and cannot be transferred out of the watershed.

Prior-Appropriation Water Rights

In general, a prior-appropriation water right is established by obtaining a water-right permit from a state. The water right is perfected, licensed, or certificated by using the water according to permit. Under the prior appropriation doctrine, water rights are "first in time, first in right". When the quantity of water available is insufficient to meet the needs of all water-right holders, the senior water-right holders may divert water, and junior water right holders may not. The concept of "priority date" is important. It is generally associated with the date that water was first put to beneficial use, or the date that a successful application for a water right was submitted. It indicates the seniority among competing users. If a water right is not used for a certain length of time, it may be considered abandoned or forfeited. Prior-appropriation rights may be sold or mortgaged separately from the land and even transferred out of a watershed.

Beneficial Use

Beneficial uses include such uses as domestic use, irrigation, stock-watering, manufacturing, mining, hydropower, municipal use, aquaculture, recreation, fish and wildlife, instream flow, etc. The amount of a water right is the amount of water put to beneficial use.

Federal Reserved Water Rights

This type of water right is established when the federal government reserves land for a specific federal purpose. Courts have held that there is an implied water right to satisfy the primary purposes of the reservation, even though the proclamation or legislation establishing the reservation does not mention water. This type of right cannot be lost through non-use and can be claimed and quantified for purposes outside state law. (The existence and nature of such rights are generally determined through administrative or court proceedings.) Examples of federal reservations include Indian reservations, national parks, national wildlife refuges, national forests, military bases, etc.


Adjudications are state administrative and court proceedings to determine the existence, priority and other characteristics of water claims in a stream basin. A water right adjudication catalogs and confirms all water rights in a basin and which party owns the water rights, binding all parties to a court decree regarding water rights. Currently the NPS participates in nine adjudications in four states: Arizona, Colorado, Idaho, and Utah.

Last Updated: December 13, 2012