Irrigation: Know Before You Grow

The marijuana cultivation landscape continues to evolve in the arid western United States. Many Western states have legalized adult-use marijuana (Alaska, California, Colorado, Nevada, Oregon, and Washington), and as a result, they have adopted a variety of rules and regulations that differ from state to state.

While states have a patchwork of regulatory and licensing systems, including a variety of, processing, testing, distribution, and sales regulations,, cultivation regulations also vary from state to state. For cultivators in a region with ongoing drought concerns, the availability of water is a complicating factor at the state level with additional complexity coming from Washington, D.C.

Water and the Federal Government

The federal government is the West’s largest water provider, and the US Bureau of Reclamation under the Obama administration issued Temporary Policy 63 in 2014 to prohibit water from federal facilities to be used for cannabis cultivation. That means in some jurisdictions where cannabis cultivation has been permitted, water may not be available to cultivators. Some jurisdictions have interpreted this ban to include federal water used to replace diverted water used by cultivations, if required by federal compact.

The cannabis industry has seen some impact as the Trump administration has rescinded some standing policies, such as the Cole Memorandum, but this Reclamation policy remains in effect until at least May 2019.

Federal water policy emerged in recent years as a significant risk in these jurisdictions. Some local water utilities and irrigation districts throughout the west, from Oregon to Colorado, have had their ability to provide water limited.

State Resources to Help Cultivators

Urban growers may find challenges arising from water utility companies, while suburban and rural growers may face challenges finding suitable groundwater, surface water rights, or hauling water. In light of legalization, some states have created resources to aid growers:


Colorado’s Division of Water Resources published “Well and Water Use in Regards to Amendment 64 and Cultivation of Marijuana” in 2014. Some of Colorado’s irrigation wells and water rights were not suitable for off-season irrigation or for use in indoor or greenhouse facilities. The document also aided applicants who wished to apply for a well permit for a cultivation site.

In addition, Denver Environmental Health released a 50+ page report in September 2017, “Cannabis Environmental Best Management Practices Guide,” which provides guidance on water filtration and purification, irrigation methods and automation, water recycling, and improving wastewater quality.

Note: While Colorado’s state marijuana license applications do not require information on water supply or sources, local licenses and zoning approvals may require this information from new applicants.


Oregon’s Water Resources Department published “Understanding Water Use Regulations: Medical and Recreational Marijuana” as a resource for new and prospective growers. While many policies have similarities to Colorado, it is important to note the 5,000-gallon per day exemption for marijuana processing activity. This does not apply to cultivation.

Note: The Oregon Liquor Control Commission requires water source documentation as part of some new license applications.


California is making history transitioning from an unregulated medical cannabis market to the world’s largest medical and adult use cannabis economy. A years-long rulemaking period is wrapping up, and multiple state agencies work cooperatively to regulate the world’s largest cannabis economy. As part of a new effort to prevent further environmental damage from cannabis cultivation, the state’s Water Resources Control Board is involved in regulatory activity.

While cultivators receive licenses from the California Department of Food & Agriculture (CDFA), all cultivator applicants are required to register with the Water Resources Control Board, and may need to navigate a complex process, depending on their water source. The agency’s priorities include reducing water supply issues, preventing illegal stream diversion and erosion, and waterway pollution prevention.

Considerations for Prospective Cultivators

With marijuana still a Schedule I substance, it is unlikely that policy changes for cannabis or cannabis irrigation will change significantly in the near future. The status quo will continue to hamper the rapid growth of a new sector in many western communities, frustrating both cannabis cultivators and water suppliers. Following are critical considerations for prospective cultivators:

  • Check the status of surface and/or groundwater rights on the property you are looking to purchase and cultivate on. This can typically be done through the state engineer or water resources department.
  • If applicable, check with the water utility that serves the area you are looking to do business in. Depending on their water source, they may not be able to supply water to cultivation.
  • Purchasing hauled water from a dispensing station may be an option in some states, but documentation of a purchasing agreement may be required prior to approval of a cultivation license.

Bottom-line, do your due diligence and understand your rights and the steps you must take to be in compliance with current state regulations with the knowledge that compliance could be challenging and expensive.

Originally published 9/29/16. Updated 3/8/19.

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