Change of Use in Colorado: Making Municipal Water Supplies Available From Irrigation Rights

Given the historic development of water rights in Colorado in the 1800s, most senior water rights are decreed for irrigation use only. In fact, currently over 89 percent of all water rights in Colorado are still used for agricultural purposes. However, there is rapid growth in Colorado, with the population expected to grow from roughly 3.8 million currently to 5.7 to 6.8 million just in the South Platte River Basin by 2050. Given the current and expected future growth, municipal water suppliers are looking more and more to agricultural water rights to meet their growing demands. Since these senior water rights can only be put to beneficial use based on their decreed uses, to utilize these water rights for municipal purposes, or any purpose other than the decreed uses, a change of use case must be adjudicated in the Colorado Water Court.

change of use case colorado


A change of use is based on the historic diversion and use of the water right, including the water that the crop consumes, the amount of the irrigation water supply that infiltrates past the root zone of the crop and returns to the local groundwater and/or surface water system, and the losses incurred in the system of irrigation water delivery. When a farmer irrigates a field, not all the water applied to the field is consumed by the crop; some of the water runs off as surface runoff and some percolates into the soil to be stored for later use by the crop, some portion percolates deeper into the ground and recharges the groundwater, and some water is lost due to infiltration from ditches and inefficiencies in the irrigation process. The water consumed by the crop, either through direct use or from the water stored in the soil, is considered the consumptive use that has historically been depleted from the stream system. This water is the only water that, according to Colorado water law, has not historically returned to the river or aquifer and is, therefore, the only water that can be used for a new purpose in a change of use case. In this way, there is no expansion of use because a municipal provider can only claim the portion of the water right that has historically caused a depletion to the river.

When applying for a change of use case with the Colorado Water Court, it may be beneficial to not only change the type of use e.g., irrigation to municipal, but also to change (a) the place of use, (b) the point of diversion, (c) the means of diversion, such as switching from a ditch diversion to a well or a pipeline diversion and/or (d) changing the water from direct application to storage. These changes all must go through the Colorado Water Court and are usually changed with one application.

Consumptive Use, Changes of Use

In a change of use for new beneficial uses of the water, the water supply entity must file an application with the Colorado Water Court, where the case will be initially referred to the Water Referee. A public notice of the application is provided in the Water Court resume, published monthly. After filing the application, any entities that have potential issues with the application have 60 days to file a Statement of Opposition (generally referred to as “opposers”). Opposers can be individual water users, other municipalities, local government agencies, the state of Colorado or anyone who opposes the change of use case. The Division Engineer will review the application and issue a consultation report with recommendations and concerns, while opposers can raise issues of concern that need to be considered by the applicant. If there are no major issues brought up by opposers, the Water Referee issues an initial ruling, which is then signed by the Water Judge. If there are major issues brought up by opposers that cannot be readily resolved, the application is re-referred to the Water Judge and the opposers and the applicant often negotiate a settlement. Almost all cases LWS has taken part in end prior to, or in, a settlement; however, if a settlement negotiation cannot be reached the case can move to a trial. Due to the complexities of Colorado Water Law and the need to provide a technical basis for any change of use case, it is necessary to have a team of engineers and lawyers to develop the case and then help address opposers concerns.


When municipalities are considering purchasing an irrigation water right to ultimately use as a municipal water source, it is important to consider the history of the water use. Often, a municipality will look for a reusable water source, i.e., water that can be used, treated, replaced to the surface or ground water source it came from and then an equivalent volume diverted and reused to extinction. An irrigation water source that has historically been used inefficiently, no matter how senior the right, will not yield as much reusable water as a water source that has been used efficiently to grow a water-intensive crop. It is best to hire an engineering firm to analyze the water use prior to purchasing a new water right. If timing allows and the right isn’t currently being maximized according to the physical supply of water and the terms of its decree, it may be beneficial to purchase an irrigation water right, lease the farm to a skilled farmer, and optimize the farming practices from the water right prior to going through a change of use case.

To learn more about this process or if you are interested in submitting a change of use case, contact us!