Water Rights & Terms

Understanding Water Rights in Colorado

Water is a precious resource in Colorado that is highly managed by the Colorado Division of Water Resources. The decrees and water laws of the State of Colorado, including permitting of wells, are enforced by seven division offices.

All water rights in Colorado follow a system of priority, which is “first in time first in right”. Any new applicant for water, receives rights that are considered “junior” (later in time) to others who hold “senior” (earlier in time) rights. This system of priority led to the development of water augmentation plans as a way for water to be available for new applicants, while still protecting those with senior water rights. An augmentation plan replaces the water the junior rights holder has used back into the stream so it is still available to the senior rights holder. 

In Colorado, when a shortage occurs, senior water rights-holders may place a “call” on the water. In those cases, upstream junior water rights-holders may be required to reduce or cease use of their water to allow that water to flow to the senior right holder. However, when that junior rights holder has an augmentation plan, they are allowed to continue using water (as designated in the augmentation plan or contract) even during a “call" – since the water they are using is being replaced back into the stream and therefore still available to the senior water rights holder. 

Individuals can apply for a water augmentation plan through Water Court, but this is a lengthy and expensive process, and therefore usually only pursued by larger entities requiring a great amount of water. Instead, many individuals who desire to use their wells for uses other than a single-family residence enter a contract to purchase water from a larger entity that has already obtained a Decree that allows for contracts with water users for out-of-priority depletions. The Summit County Water Court Decree contains the specifics of our Water Augmentation Plan.

Water Terms

Accessory Unit

A second, subordinate dwelling unit located on the same lot as a 1-family dwelling unit, where the subordinate unit is incorporated into either the primary unit or a garage serving the primary unit, and the subordinate unit has separate cooking facilities from the primary unit. 

Acre-Foot (AF)

An acre-foot is the typical unit of measurement used for large volumes of water. It is actually defined as the volume of one acre of surface area to a depth of one foot, which can be envisioned as enough water to cover an acre of land (about the size of a football field) to a depth of one foot. In other terms, an acre-foot of water can be converted to about 326,000 gallons. 

Augmentation Plan

A court-approved plan that allows water users to divert water out-of-priority so long as adequate replacement is made to the affected stream system, thereby preventing injury to the water rights of senior users.


When there is insufficient water in a stream, river, or aquifer to meet the water right of a senior user, the senior water right holder may place a “call” on the river. When a call is present during water short time periods, upstream junior water right holders may be required to reduce or cease their use of water to allow water to flow to the senior right holder.

Consumptive Use

Any use of water that permanently removes water from the natural stream system. 


A final court decision regarding a water rights case. Once a decree has finalized a water right, the right is administered by Colorado’s Division of Water Resources.


The removal of water from its natural course or location, or controlling water in its natural course or location by means of a ditch, canal, flume, reservoir, bypass, pipeline, conduit, well, pump or other device.

Ground Water

Water found below the earth’s surface.

Junior Rights

Water rights that are more recently established than older or more senior rights. Junior rights may not have the right to divert if their diversion causes a senior user to lack the full beneficial use decreed to the senior water right.

Non-consumptive Use

Water diverted for use that is not consumed or permanently removed from the river system. For example, water withdrawn for purposes such a hydropower generation is returned to the river. It also includes uses such as boating or fishing where the water is still available for other uses at the same site.

Priority Appropriation Doctrine

A legal concept in which the first person to appropriate water and apply it to a beneficial use has the first right to use that amount of water from that source. Each successive appropriator may only take a share of the water remaining after all senior water rights are satisfied. This is the historical basis for Colorado water law and is sometimes known as the Colorado Doctrine or the principle of “first in time, first in right.”


The right of an earlier (senior) appropriator to divert from a natural stream in preference to a later (junior) appropriator.

Priority Date

The date of establishment of a water right. The rights established by application have the application date as the date of priority.


Water that flows on the earth’s surface to streams, rivers, lakes, and oceans. 

Senior Right

Water rights that are decreed earliest in priority by the water court. 

Water Right

A property right to make specific beneficial use of a particular amount of water with a specified priority date.


An area from which water drains to a given stream or river or river system.