Colorado's Green Law: Private Wells Included?

The Colorado Green Law pertains to water well permits, water rights, and the monitoring of water usage and quality. While the law does not regulate water quality for private wells, it does require permits for new wells and outlines specific rules for well construction and maintenance. The law also establishes a priority system for water allocation, giving senior rights to the first appropriator of water. This means that the initial appropriator's water needs must be met before any subsequent, more junior rights can be fulfilled. The Colorado Division of Water Resources is responsible for issuing permits, administering water rights, and ensuring compliance with the law.

Well permits and registration

The process of obtaining a well permit in Colorado can be complex, but there are resources available to help navigate the system. The Guide to Colorado Well Permits, Water Rights, and Water Administration, issued by the Colorado Division of Water Resources (DNR), is a helpful resource that answers basic questions about the permitting process, the types of permits available, and the rules governing the use of private wells.

To obtain a permit for a new or replacement well, you must first complete the appropriate application form, which can be accessed through the DWR's website. The DWR accepts applications by email, and associated fees can be paid online. The review process for complete applications can take up to 49 days.

In most cases, a licensed water well driller will help with the required paperwork. Once the form is completed and construction reports are filed with the State Engineer, most well permits are valid for the life of the well and do not need to be renewed.

It is important to note that wells for most uses, such as irrigation, are considered "non-exempt" and are subject to the priority system, requiring an augmentation plan. However, most private domestic wells in Colorado are "exempt" from this system and do not require augmentation. These exempt wells are typically limited to 15 gallons of water per minute and are restricted to non-evaporative wastewater systems.

For those purchasing property with an existing well, it is important to determine if the well is registered and permitted. Unregistered exempt wells in use before May 8, 1972, can be permitted for historic uses. Exempt wells installed on or after May 8, 1972, must have a permit, and wells drilled without permits after this date are considered illegal.

Information on all registered well permits in Colorado can be found through the DWR's Well Permit Search Tool and Map Viewer Tools. These tools provide details on the allowable uses of the well, the original permit application, and any available well construction and pump installation records.

Additionally, special Use and Measurement Rules apply to some Groundwater Basins and River Basins. These rules can be found on the DWR's website under the Well Metering subpages.

Water quality and safety

The responsibility for ensuring the safety of water drawn from private wells falls primarily on the individual well owners. They do not benefit from the government's health protections afforded to public water systems, which are subject to frequent analysis, testing, and reporting requirements.

Groundwater wells are the main source of water for most homeowners in rural areas of Colorado. Before drilling a groundwater well, a permit from the Colorado Division of Water Resources, also known as the State Engineer's Office, is required. Most private domestic wells in Colorado are "exempt" from administration in the priority system and do not require augmentation. However, wells for other uses, such as irrigation, are considered "non-exempt" and are administered within the priority system.

The quality of groundwater can vary significantly across Colorado, ranging from excellent in deep aquifers to poor in some alluvial aquifers due to contamination from agriculture, industry, or urban development. The only reliable way to determine if water is safe for drinking is through laboratory analysis for bacteria and chemical constituents.

In terms of water quality standards, Colorado is authorized by the EPA to establish its own standards, which form the legal basis for controlling pollutants entering waterways. These standards describe the desired condition of a waterbody and the levels of constituents required for specific uses such as recreation, water supply, aquatic life, and agriculture.

Colorado's surface water quality standards consist of three core components: classified uses, criteria, and antidegradation designations. The Water Quality Control Commission adopts standards for both surface water and groundwater, and they routinely review and update these regulations through a public hearing process.

In May 2024, the Colorado Senate Bill SB24-037, also known as the "Study Green Infrastructure for Water Quality Management", was signed into law by Governor Polis. This bill recognizes the potential of green infrastructure to reduce costs, benefit the climate, and protect water resources. It directs the University of Colorado's Mortenson Center in Global Engineering and Resilience (CU Boulder) and Colorado State University (CSU) to collaborate with the CDPHE in exploring the feasibility of green infrastructure to address water quality concerns in the state's rivers and reservoirs.

Well construction rules

Before drilling a groundwater well in Colorado, a permit from the Colorado Division of Water Resources (also known as the State Engineer's Office) is required. The type of permit needed depends on the intended use of the well. Most private domestic wells are "exempt" from administration in the priority system and do not require augmentation. These exempt wells are typically limited to 15 gallons of water per minute and are restricted to in-house use for properties smaller than 35 acres.

Wells for other purposes, such as irrigation, are considered "non-exempt" and are subject to the priority system. They require an augmentation plan to replace water in over-appropriated basins. The use of non-exempt wells is governed by the terms of their permits, and they are junior in priority to existing senior water rights.

The Division of Water Resources provides several types of well permit application forms, including those for constructing a new well or registering an existing one. The specific rules and regulations for well construction vary depending on the location of the well, with additional rules applying to wells in the Denver Basin and Designated Basins.

It is important to note that the government does not regulate the water quality for private wells. The responsibility for water safety falls on the individual well owners, who must ensure the suitability of their water supply through laboratory analysis for bacteria and chemical constituents.

Water rights and allocation

The simplified way to explain this system is often referred to as "first in time, first in right". An appropriation is made when an individual physically takes water from a stream (or underground aquifer) and puts it to beneficial use. The first person to appropriate water and apply it to use has the first right to use that water within a particular stream system. This person then becomes the senior water right holder on the stream, and that water right must be satisfied before any other water rights can be fulfilled.

In Colorado, water right applications are under the jurisdiction of the water courts. There are seven water courts, one in each of the seven major stream basins in Colorado. Some junior water rights holders may be allowed to use water out-of-priority under a "futile call" determination by the Division Engineer. This permits the junior user to divert water out-of-priority to a beneficial use when the diverted water would not reach a downstream senior water right holder at the time and place of their need.

The Colorado Division of Water Resources (DWR), also referred to as the State Engineer's Office, administers water rights, evaluates and oversees the well permitting process, and inspects wells and dams. The DWR has several types of well permit application forms, and most private domestic wells in Colorado are "exempt" from administration in the priority system and do not require augmentation. However, wells for most other uses, such as irrigation, are considered "non-exempt" and are administered within the priority system.

Groundwater wells are the principal source of water for most homeowners in rural areas of Colorado, with over 200,000 permits for groundwater wells currently issued. Most of these wells are used for households and are considered exempt from the administration within the water rights priority system. They require a permit from the State Engineer and are limited to 15 gallons of water per minute. Some exempt wells are further limited to in-house use only when lot sizes are smaller than 35 acres.

Wells for most other uses are considered non-exempt and are administered within the priority system. Their use is limited by the terms of the permit, and since they are junior in priority, they must have augmentation plans to replace water in the stream system in over-appropriated basins. The Colorado Ground Water Commission, with assistance from the DWR, is responsible for adjudicating groundwater rights and issuing large-capacity well permits in Designated Groundwater Basins in eastern Colorado. There are eight Designated Groundwater Basins with 13 groundwater management districts within these basins.

Well pumping rates

The pumping rate for exempt wells is limited to 15 gallons of water per minute, with some further restricted to indoor use only for properties smaller than 35 acres. Non-exempt wells, on the other hand, are administered within the priority system and must have augmentation plans.

Additionally, specific river basins in Colorado, such as the Republican River Basin, the Arkansas River Basin, the Rio Grande Basin, and the South Platte River Basin, have rules requiring certain wells to have a measurement device installed and verified by a certified well tester. These wells typically have a pumping rate greater than 50 gallons per minute (gpm), while exempt wells pump less than 50 gpm and are used for residential or limited commercial purposes.

It is important to note that the availability and quality of groundwater can vary due to changes in subsurface geology, and wells may go dry during droughts or when an aquifer is over-pumped.

Frequently asked questions