Colorado has some of the most sought after, hardest working, and highly regulated waters in the United States. The Colorado River is a 2,330-kilometer of the 1,450-mile river known as the “Beating Heart of the American Southwest.” It provides water to 35 million people and irrigating 4 million acres of farmland. Water comes from its headwaters in the Rocky Mountain National Park in north-central Colorado and passes through eleven different national parks and monuments across varied landscapes of the country’s seven states and two countries. Being the heart of the American Southwest, it is a critical source of water supply for agriculture, manufacturing industries, and communities from Denver to Tijuana. Colorado River fuels a $1.4 trillion economy per year that its ultimate demise will cripple the millions that depend on its glorious waters. 

The Colorado River is home to a dynamic ecosystem of wildlife, communities, and economies and provides a lifeline to various bird species. It is also a source of economic activities in the state and downstream of Colorado. Visitors are treated not only to the pristine landscape but also to many interesting mammals, reptiles, amphibians, and fish. The Colorado River is home to beavers. However, because of the strong current, beavers cannot build their dams on the river. Instead, the ingeniously build dens along the river’s banks where the current is slower. 

When visiting, you might also find muskrat, though extremely rare. They also build their dens along the river’s shorelines. Otters that made the river their habitat have since left the park. More than 40 reptile species inhabit the river and the Grand Canyon, including snakes, lizards, and other small mammals. Also, native fish species like the minnows, speckled dace, bluehead suckers, and flannelmouth were able to adapt to the Colorado River’s cool waters. If not millions, thousands of people make the trip to Colorado to experience the many recreational opportunities the river offers. Activities like fishing, boating, wildlife viewing, hiking, water paddling, and backpacking contribute an average of $26 billion annually. Following decades of mismanagement and wasteful use of resources, the river can no longer sustain its waters’ demand. 

Colorado River

The Colorado River has been dammed, diverted, and its flow slowed down by reservoirs. One might say that these efforts, though directed towards development, has strangled the life out of a once-thriving natural wonder. In its former glory, the river had the most extreme flows of all the United States rivers. Its flows range from 2,500 cubic feet per second during the lows in winter to 100,000 cubic feet per second in the summertime. In fact, in 1884, it has recorded a peak flow of 384,000 cubic feet per second, which reached Arizona. This proved that extreme flows from the river are too capricious and unpredictable to support civilization.

History of the United States water development efforts would tell us that a prevailing theme is a conflict among different users. Just like any limited resource, conflict arises when the use of limited water supplies is disputed, especially during drought periods. Government efforts to build physical infrastructure for managing the Colorado River’s water resources are designed to address the conflict between end-users and states that depend on the river. Creating systems that store water during the wet season to counter the demands during drought is among the federal government’s many policies. This has proved effective in ensuring that water supplies are available and reliably met. 

To contain these extreme flows, humans have endeavored to build a network of sophisticated, expensive dams and reservoirs, canals, aqueducts, pipelines, and flumes to slow down and divert the water flow. Today, the river and its tributaries are collectively known as the “Colorado River Basin,” including the Green, the Gunnison, the San Juan, the Virgin, Little Colorado, and the Gila Rivers. The Colorado River basin is known the world over for its breathtaking canyons, natural landscapes, panoramic view, and widespread aridity. It is mostly arid as the Basin lies within the country’s driest regions. The Basin drains 242,000 square miles or one-twelfth of the country’s continental land area. On top of that, it also drains 2,000 square miles in Mexico. 

Western states, including Arizona, California, Colorado, Nevada, New Mexico, Utah, and Mexico, benefit from the Colorado River Basin. All of them are a party to the Colorado River Compact signed on November 24, 1922, in Santa Fe, New Mexico. The Colorado River Compact divided the Basin into two parts – Upper Basin and the Lower Basin – with a division point in Lee Ferry. The Upper Basin benefits states of Arizona, Colorado, New Mexico, Utah, and Wyoming. They receive water that naturally drains into the Colorado River system above the division point. While the Lower Basin benefits the States of Arizona, California, Nevada, New Mexico, and Utah that receives natural water flow below Lee Ferry. 

The Colorado River Compact granted an annual exclusive, beneficial consumptive use of 7,500,000 acre-feet water in perpetuity. It also gave the Lower Basin an additional right to increase its annual beneficial consumptive use by 1,000,000 acre-feet. Despite these grants, the Compact did not apportion water to any State. This allowed states in both Upper and Lower Basin to enter into separate agreements to apportion beneficial consumptive use among themselves. 

Law of the River and Water in Colorado 

Water rights in Colorado are unique compared to other states. As it is a headwater state, it is the origin of four regional watersheds and major basins: the Arkansas (Southern front range), Colorado (Western Colorado), South Platte (Missouri), and Rio Grande River (Southern Colorado) basins. Colorado is dependent on these river systems for its economy, environment, and lifestyle. It supports the state’s farms and ranches and provides the citizen’s clean, safe, and reliable drinking water.

However, the Colorado River is shared by states and the federal government, American Indian tribes, and Mexico. As a result, many compromises, interstate compacts, a United States Court decree, and an international treaty were put in place to ameliorate the resource’s conflicting interests. All these agreements, decrees, and regulations are collectively known as the Law of the River.

What makes the Colorado River unique from the rest of the world is managed and operated. The Law of the River consists of documents apportioning the water resources and regulating the river’s use and management among the seven basin states that signed the Colorado Compact River Compact and Mexico.

  • The Colorado River Compact of 1922, the cornerstone of the Law of the River. The compact was entered into in 1922 by the seven Colorado River Basin states and the federal government and clarified the relationship between the Upper and Lower Basin states.
  • The Boulder Canyon Project of 1928 is a significant component of the Law of the River, which had the following effects:
    1. Ratified the 1922 Colorado River Compact;
    2. Allowed construction of the Hoover Dam and related irrigation systems in the lower Basin;
    3. Apportioned 7,500,000 acre-feet of water in perpetuity to the lower basin states according to the following volumes: 2,800,000 acre-feet of water to Arizona, 4,400,000 acre-feet of water to California, and 300,000 acre-feet of water to Nevada. 
    4. Lastly, it delegated the Interior Secretary to be the sole contracting authority for the Colorado River water use in the lower Basin.
  • California Seven Party Agreement of 1931 agreed that the long-standing conflict between the California agricultural and municipal interests over the river’s water priorities. The conflict involved seven claimants – Palo Verde Irrigation District, Yuma Project, Imperial Irrigation District, Coachella Valley Irrigation District, Metropolitan Water District, and San Diego. A consensus was reached through the agreement regarding the amounts of water to be allocated to each claimant. 
  • The Mexican Water Treaty of 1944 an important treaty that committed 1,500,000 acre-feet of water to Mexico.
  • Upper Colorado River Basin Compact of 1948 formed the Upper Colorado River Commission and signed on to apportion 7,500,000 acre-feet of beneficial water use to the Upper Basin according to the following: 51.75% to Colorado, 11.25% to New Mexico, 23% to Utah, and 14% to Wyoming.
  • Colorado River Storage Project Act of 1956 authorized the construction of Glen Canyon, Flaming Gorge, Navajo, and Curecanti dams to regulate the river, power production, and irrigation as provided in the Upper Basin-wide water resource development plan.
  • The Arizona v. California U.S. Supreme Court Decision of 1964 a decision rendered by the Supreme Court which settled the 25-year-old conflict between Arizona and California. The dispute began when Arizona pushed its plans to build the Central Arizona Project in the hopes that it could use the full of Colorado River’s apportionment. Naturally, California objected to the claim anchoring its defense on prior appropriation doctrine, precluding Arizona from constructing the project. California’s arguments were rejected by the Supreme Court ruling that lower basin states, including Arizona, have the right to appropriate tributary flows from the Colorado River. Therefore, the doctrine of prior appropriation did not apply to the apportionments in the lower Basin.

The Supreme Court issued two decrees, Supplemental Decree and Consolidated Decree, both with the end goal of addressing conflicting rights on the Colorado River.

Water Supply in Colorado

Colorado’s water supply consists of renewable surface water and non-renewable groundwater. Such sources include rivers and precipitation from rainwater and stormwater. Based on research, an average of 14.8 million acre-feet of water from rivers is generated each year. Of this, about 2/3 flow outside the state’s jurisdiction. 

A headwater state, Colorado, has a major role in the Law of the River. It is a party to nine interstate water compacts or agreements. Under these agreements, the state shares renewable water from the river systems that originate in its territory. As of 2017, 86% of the 1/3 that remains of their water is used for agriculture. This means that Colorado uses only 14% of the renewable water available for its exclusive beneficial use. Thus, this results in a reliance on non-renewable water supplies. An example of such a water supply is the Denver Basin aquifers.  In an ideal world, aquifers may be used as a fallback during a severe drought. However, currently, water districts and municipalities are moving away from these aquifers and are looking for other renewable surface water sources.

One way of collecting invaluable renewable water resources is through rainwater harvesting. Rainwater is a natural and helpful resource that can be passively harvested. It provides landscapes with life-sustaining water and results in an abundance of moisture for weeks or months after rain. The precipitation in rainwater depends on Colorado’s annual hydrology cycle, starting with snow buildup in the winter and early spring. The majority of this rain comes from snow. Snow, as we now know, serves as natural storage of water. Many of the state’s mountains are covered with thick snowcaps reaching more than 300 inches. A spring runoff follows this, then rainstorm activity caused by storms originating in the Pacific Ocean in the late summer. 

Colorado’s Elevation

Due to its high elevation landscape, the stored water will be released in April, May, or June. This water produced by rainfall or snowmelt infiltrates into the soil and rock layers and fills aquifers. Aquifers are then pumped out for water supply to be used in our homes, agriculture, and various other industries. The excess water runs off to the streams for future use and other purposes.  

According to a guide published by Colorado’s government, the state has an average annual statewide precipitation of 16 inches. Each year, San Luis Valley, as the driest part of the state, has only 7 inches of precipitation. The mountains are the wettest areas, and some parts get 50 inches of rain annually. This is where Colorado’s unique geographical landscape comes into play. Regions and zones above 10,000 feet elevation receive an average of 25 inches of rain per year. 

But year-to-year, Colorado’s rain and precipitation levels vary remarkably from long seasons of drought to sudden surge of rain- and stormwater. Without the much needed human intervention, a large percentage of our water would remain underground or runoff to streams, rivers, and towards the ocean. This will ultimately leave us with little to no useable water for our daily consumption. Rainwater Harvesting is, without question, one of the easiest ways for us to intervene and actively participate in conserving our meager water resources. 

Rainwater harvesting in Colorado

Rainwater harvesting, or what is also known as rainwater collection, is the process of storing, directing rainwater, and putting it to beneficial use. However, water that usually flows to landscapes is not considered as rainwater harvesting. Those that involve rainwater collection from rooftops, concrete patios, driveways, and other surfaces is what we consider as rainwater harvesting. 

Rainwater collection systems can be either simple and inexpensive to complex and costly. Rainwater collection from the rooftop usually involves simple processes consisting of gutters, downspouts, and storage containers. Gutters are the most basic form of rainfall harvesting system, which drain into a downspout and are then directed to gardens and yards. A more complex system involves cisterns and filtration systems to remove any unwanted contaminants. Water is drawn from cisterns directed for irrigation, gardens, landscaping, and other non-potable use. Barrels or plastic tanks with lids are commonly used as inexpensive rainwater storage systems to reduce evaporation and bar access for mosquitoes to breed. Sophisticated systems have first flush diverters to capture initial rain that may carry dirt from roofs.   

Why is Rainwater Harvesting Previously Illegal in Colorado?

Rain harvesting in Colorado has been traditionally illegal because it is believed to impede senior water rights. Although we may consider the practice a win-win solution to our growing problem of developing new water sources, it has been fraught with conflicts and tensions. Rainwater collection has pitted rural farmers and other agricultural interests against urban and suburban homeowners who installed a rainwater collection system in their backyards. The Western States abide by the water law based on the prior appropriation doctrine. The doctrine creates a “first in time, first in right” system where water rights become tied to when a user may be a person, community, municipality, or state, diverts surface water to use it. 

When is there appropriation? 

There is appropriation when water is taken from a stream or underground aquifer for some beneficial use. The rules state that the first person to appropriate water within a particular area has the first right to use that water after receiving a court decree verifying their priority status. Such a person who has this priority becomes the senior water right holder on the stream, and their water right must be satisfied before any other water rights can be fulfilled. There is a valid water right when water is diverted for beneficial use and made available for diversion. Beneficial use may include traditional usage of water in agriculture and supply for cities and towns, including drinking water. It may also include environmental and recreational flows. 

Legalizing Rainwater Harvesting in Colorado

Water rights in Colorado are mainly governed by the prior appropriation doctrine. This system provides for the water allocation controls how much water, the types of uses allowed, and when those waters can be used. Since water rights operate as property rights, the risk of giving senior appropriators to take claim over any water resource may be given effect by state statutes and regulations. Prior appropriators are given preferential rights in diverting and using rainwater for irrigation and other uses. Usually, the ones that get this privilege are people involved in agriculture and irrigation.

The issues lie when a majority of the homeowners in the urban and suburban areas collect rainwater. Rainwater harvesting, when done in the aggregate, would reduce the amount of water that flows to the agricultural areas for irrigation. The consequence of the rainwater harvesting effort of private persons is in defiance of farmers’ senior water rights and other agricultural industries. Homeowners, therefore, pushed the state to enact legislation that will legalize and explicitly permit rainwater harvesting.

Colorado Rainwater Harvesting Laws

Collecting rainwater for beneficial use was historically prohibited in Colorado as it poses potential injury to senior water rights. Safeguarding senior water rights holders is a top priority. For this reason, diverting and storing water is only allowed in rainwater barrels once certain requirements are satisfied. Consequently, it is illegal to stop the flow of water in the west without acquiring water rights. For an individual, homeowners, commercial landowner to use simple rain barrels, dams, and ponds, specific permits must be secured from concerned agencies. Despite this, it has not been illegal to divert downspouts directly into the landscape.

A 2007 study conducted by the Colorado Water Conservation Board, rainwater and snowmelt harvesting can reduce demand for outdoor water use by 65 to 88 percent. This is approximation will be possible when harvested rainwater is used combined with active water management techniques, such as moderate conservation and water-wise conservation. It is worth noting that when the study was conducted in 2007, rainwater harvesting was still illegal in Colorado. This signifies that the conservation method is seen as a possible solution for Colorado’s municipal water gap.

Colorado is an environmentally progressive state, but it fell behind Utah and California in legalizing rainwater harvesting. Utah enacted state legislation that authorized rainwater harvesting in 2010, while California’s Rainwater Capture Act was enacted in 2012. Over the last ten years, rainwater harvesting in Colorado’s state moved from being illegal to be allowed under strict and limited circumstances. This was in 2015 when the state Water Plan was published. A year after, it was allowed more extensively and with little limitations. Colorado’s love-hate relationship with collecting, harvesting, and storing rainwater is a reflection of its high regard for the prior appropriation doctrine. 

The same research found that only 3% of rain reached the stream or groundwater. To address this problem, the Colorado legislature enacted two legislation pieces in 2009 – Senate Bill 80 and House Bill 1129. This gave residents the right to collect and use rainwater.

Senate Bill 09-80

Under Senate Bill 09-80, there are special circumstances where rural residents may use rainwater. Certain types of good owners are allowed to use rainwater. This type of owner or qualified resident is someone who is issued exempt good permits. Holders of an exempt well permit are allowed to make use of a rooftop precipitation collection system. A qualified rural resident must apply for a collection system permit. Such applications can be obtained from the Colorado Division of Water Resources. 

The Division issues the permits, monitors streamflow and water use, administers water rights, and inspects dams for safety guidelines. It is also administratively responsible for maintaining databases of Colorado water information. It cooperates with various local groundwater management districts to ensure statewide monitoring of groundwater levels. Most importantly, it represents the state in the interstate water compact proceeding. A leader in Colorado’s water community and the western United States, the Division of Water Resources strive to effectively and efficiently conduct its role as steward of Colorado’s water resources. 

How Do I Obtain Well Permit?

The State Engineer is tasked with promoting ways to maximize the beneficial use of Colorado’s limited water resources. Groundwater pumped through wells is an important part of the state’s water supply. Homeowners and landowners are encouraged to construct wells, but the application must go through the process. Permits are issued and maintained by the State Engineer according to the Colorado Revised Statutes.

There are two different kinds of well, exempt from the administration of water rights and non-exempt, which operates under the priority system.

  • Exempt Wells Permits, issued to several types of exempt wells. Use may vary depending upon the situation and location but are generally limited. Limitations are specifically provided under the conditions of approval stated on the permit after it is issued. Limitations may include the pumping rate. In most cases, it is limited to no more than 15 gallons per minute. 

An exempt well permit will not be issued when your municipality or a water district can provide a water supply to your property. Lastly, only one exempt well permit will be issued per lot. 

Here are the different types of exempt wells:

  1. Household Use Only Wells issued for ordinary household uses and can only be applied once for a single-family dwelling. Use may not extend to outside water or livestock watering.
  2. Domestic and Livestock Wells issued upon application of owners of tracts of land of 35 acres or more. The well exempt application must indicate that it is the only well on the entire tract of land.
  3. Commercial Exempt Wells, water extracted from commercial exempt may only be used in commercial businesses, like convenience stores. It is only limited to pumping one-third-acre foot of water of 108,600 gallons of water per year.
  4. Unregistered Existing Wells, this permit is issued for existing wells put to beneficial use before May 8, 1972. It must have served up to three homes, have irrigated gardens and landscapes, and have watered domestic animals and livestock. The well can be registered for historic use.
  5. Monitoring and Observation Wells, permit specifically issued for wells to be used to monitor groundwater and collect water samples for quality monitoring.
  6. Replacement Wells, a permit to be issued for replacing or deepening existing wells. Uses indicated in the original exempt well permit may be carried over to the replacement well. 
  7. Geoexchange Systems is the permit issued upon applying for the construction and installation of loop fields in the geo-exchange systems.

These good permits allow for household uses only, which means that the rainwater collected can only be applied to non-potable uses in the residence. If the permit allows for household uses and outdoor uses, including lawn and garden irrigation and or animal water, it can only be used for such purposes. A resident that is qualified for an exempt well permit may collect rainwater under S.B. 09-080 as well as 110 gallons of water under H.B. 16-1005 as long as they follow the restrictions under the two laws. 

  • Non-Exempt Wells Permits are those permits issued for any other type of wells for use other than those mentioned above. The non-exempt well permit allows pumping rates and annual withdrawals of groundwater above that allowed in exempt wells permit. For new non-exempt wells, it must be located more than 600 feet from any other existing or production well. Most importantly, the production well must not be owned by the applicant. The State Engineer will conduct an inspection and a hearing, and after finding that circumstances warrant the issuance of the permit, it will do so.

The following are non-exempt wells:

  1. Irrigation, Commercial, Municipal, & Industrial
  2. Subdivision Wells with Augmentation Plans 
  3. Replacement Wells, as the name suggests, it is for purposes of replacing an existing well. 
  4. Gravel Pit Wells, issued for gravel pit operations to protect exposed groundwater.
  5. Pond Wells, for the construction of new ponds and permitting existing ponds that expose groundwater.
  6. Recovery Wells, issued for purposes of removing contaminants from groundwater. 
  7. Geothermal Wells, for purposes of monitoring and exploring geothermal resources.
  8. Dewatering Systems
  • Other Structures
    1. Monitoring and Observation Holes
    2. Test Holes (that penetrate through a confining layer) –
    3. Dewatering Wells

Application for Wells Permit

The application includes a notice of intent to collect precipitation and a description of how it may be captured. In this system, any rain barrel size is allowed. It only requires that the water must be collected from the roof, and the rainwater must be used for the uses under the resident’s exempt well permit.

 To qualify for the permit, the following conditions must be complied with:

  • You are on a residential property
  • You may use an exempt well 
  • You collect rainwater exclusively from the rooftop of the residence
  • You use the water for allowed uses based on your permit 

House Bill 1005

House Bill 1005 was enacted in 2016 to affirm that collecting precipitation from rain barrels does not interfere with existing water rights. More so, that the use of a rain barrel does not constitute a water right. Thanks to this law, most Colorado landowners are now allowed to use rain barrels to collect rainwater. Residents can now catch and store rainwater for future use on their property.

The Bill permits 110 gallons of storage capacity for rainwater from rooftops. However, it is required that the collected precipitation must be used on the property where it is collected only for outdoor purposes. An example of such use is using the collected rainwater to irrigate outdoor lawns, plants, or gardens. To ensure compliance, state engineer tracks adoption and usage among homeowners. 

Before House Bill 16-1005, rainwater collection was not permitted except under specific circumstances. The bill has restrictions on rainwater collection. Under this law, to use rain barrels legally in Colorado, several restrictions must be followed depending on your residential. 

Generally, rain barrels are installed at single-family households and multi-family households (with four or fewer units). Each household is only allowed to have a combined storage of two rain barrels amounting to 110 gallons. It cannot exceed that. These rain barrels can only be used to capture rainwater from rooftops and downspouts. The collected rainwater must be used to water outdoor lawns, plants, and gardens on the same property from which the rainwater was stored. It can’t be used as drinking water or indoor water. 

Furthermore, arguably the most important point, rainwater using rain barrels does not constitute a water right. However, if the use of rain barrels curtail another individual’s water right, that individual may file a petition. It must be proven that the good owner gravely impacts the holder’s ability to receive the water they are entitled to and injures their ability to enjoy his or her acquire water rights.

House Bill 1129

Another rainwater harvesting law is House Bill 09-1129. 

House Bill 09-1129 is legislation that is beneficial for homeowners and real estate owners. This law mainly allows pilot projects for beneficial use where the CWCB is directed to establish criteria and guidelines for the application and selection process of a new development pilot project. These pilot projects are done to evaluate the feasibility of rainwater harvesting as a conservation measure. Once approved, these pilot projects may harvest a rainwater runoff volume equivalent to the pre-developed consumptive use of the native vegetation. 

Moreover, Under HB-09-1129, developers participate while individual landowners are not eligible. Each project operates following an approved and water court-sanctioned plan. While a homeowners’ association is given the authority to impose aesthetic and location requirements for the rain barrels, it cannot ban rain barrels by its members. 

To check out frequently asked questions about the rainwater harvesting laws, please visit this website.