The first rules of water usage in Colorado came with the 1859 gold rush. Any miner who was the first to divert water for use had the right to continue to use that water over any miner who arrived later. The next miner had the right to divert water for use over anyone arriving later, but had to defer to anyone who had been there first. This system of water use eventually became the Doctrine of Prior Appropriation, or the first-in-time, first-in-right doctrine, and was written into the Colorado Constitution. Its main points are:

  • To obtain a water right, the water must be put to beneficial use
  • The preference of water uses in order order: domestic, agricultural, and industrial
  • Water rights may be bought, sold, inherited, moved from one place to another, or changed from one type of use to another, as long as the change does not interfere with other water rights

The water rights laws in Colorado were written using four basic principles:

  1. All surface and ground water in Colorado is a public resource for the beneficial use by public agencies and private persons;
  2. All water right is a right to use a portion of the public’s water resources;
  3. Water rights owners may build facilities on the lands of others to divert, extract, or move water from a stream or aquifer to its place of use; and
  4. Water rights owners may use streams and aquifers to transport and store water.

Under these principles, water is distinguished between natural stream water, which includes surface water and tributary ground water, and deep ground water, which includes designated ground water, non tributary ground water, and Denver Basin ground water.

Colorado’s prior appropriation system, a legal procedure that enables water users to obtain a court decree for their water rights, is mandated by Colorado’s Constitution. It is the “priority doctrine” which regulates the use of surface and tributary ground water and determines which water users have priority (as in the example with the miners).  Under this system, those with senior water rights, meaning those who have had official rights the longest, are the last to be cut off from their water supply during water shortages, even when the water held by someone with junior, or more recently obtained water rights may have a more beneficial use for the water. Colorado water laws do not distinguish between beneficial uses except for general categories, such as agricultural and domestic uses, which goes back to first-in-time, first-in-right.

To secure a water right, you must first appropriate the water. Appropriation occurs when a public agency, private person, or business puts unappropriated (basically, unclaimed) water to beneficial use. Only previously unappropriated surface or tributary ground water can be appropriated.  In addition, the appropriator must not only put the water to beneficial use, but must also have feasible plan to diver the water so it is under their control and able to be applied to the proposed beneficial use. Under the priority doctrine, a person can obtain direct flow rights to take water directly from a stream to its place of use or for storage in a reservoir for later use.

Finally, the appropriator must also demonstrate that the water right being applied for will not cause injury to existing water rights holders. The process of court approval for appropriation is called adjudication. It sets the priority date of the water right, its source of supply, amount, point of diversion, and type and place of use. This information helps to provide an orderly system for state officials to distribute water according to decreed water right priority dates.


One of the most important developments in the administration of Colorado water rights was the 1969 Colorado Ground Water Management Act, known as the 1969 Act, which was passed to address court approval of water exchanges, changes of water rights, and augmentation plans. The 1969 Act allowed new uses of over-appropriated streams and aquifers, such as for municipal, environmental, and recreational uses.

The primary purpose of the Act was to integrate the appropriation, use, and administration of tributary ground water with the use of surface water to maximize the beneficial use of all water in Colorado by protecting senior water rights and achieving maximum water utilization. The 1969 Act established water divisions, Division Engineers to be appointed by the State Engineer, Water Judges, Water Referees, Water Court, and Water Clerks.

The information provided on this website is not intended to provide legal advice. Colorado water law is always changing and is constantly revised as new technology and uses are created. For specific questions on legal issues and rights you should contact and attorney who specializes in water law.