Report: Unlicensed Cannabis Grows Use More Water Than Licensed Grows in California

The University of California, Berkeley (UCB) recently published a scientific brief in February regarding illegal water use for cannabis plants.

Entitled “Water Use: Cannabis in Context,” the brief was conducted by individuals at the Berkeley Cannabis Research Center, which is part of the College of Environmental Science Policy & Management. The Cannabis Research Center has been reviewing cannabis water use since 2017, and the most recent brief is split into four sections posed with a question.

First, “How much water does cannabis use relative to stream flow?” explains that cannabis water use in regions along the Northern California coast and semi-inland areas (primarily Humboldt and Mendocino County) represents a “small fraction” of surface water supplies year-round, and especially during the months of July, August, and September. However, cannabis grows aren’t spread out evenly amongst these areas, with many farms gathered near one another. In those areas, “cannabis water demand represents >10% of available supplies during the dry season.” Researchers also make an important note that the watershed samples they refer to include demand mainly from unlicensed farms.

The researcher’s second section addresses the comparison between water demand between unlicensed versus licensed farms. “Unlicensed cannabis accounts for significantly more cultivated area than licensed cannabis farming and therefore has a much larger water demand footprint,” researchers explained. “Furthermore, because unlicensed cannabis farms often have little to no water storage on-site, water is extracted from watersheds on demand, which tends to peak in August.”

Ultimately, unlicensed farms consume much more than licensed farms throughout the year. “Water demand for unlicensed cultivation therefore exceeds that of licensed cultivation to an even greater extent in the driest time of year when stream flow is lowest,” the authors stated, recommending that incentives be provided for licensed farmers to be able to obtain or retain their existing licenses while “increasing off-site stream storage” to use as irrigation during the summer months.

The third section explores how much residents in Humboldt and Mendocino Counties consume in comparison to the amount of water that licensed grows utilize. Researchers studied 91 watersheds and found that resident’s demand for water usage far exceeded that of licensed cultivators by 97%. “On average, licensed cannabis farm demands are one-tenth the amount of water as residential demand,” the brief states. “Water demands for other forms of agriculture in the region far exceed those of cannabis and residential use.”

Finally, the last section examined water used licensed cannabis grows and found that those cultivation sites only used 4% or less of streamflow in the month of August, some even without additional water storage. “If licensed cannabis farms had enough water storage capacity to accommodate at least half of their annual water demand, there would be no watersheds among those sampled exceeding 2% of their estimated streamflow availability,” the authors concluded. “If licensed cannabis farms had storage capacity equivalent to their annual water demand, licensed cultivation would not require more than 1% of available flow in any sampled watershed.”

The release of this brief is well-timed to educate voters as spring approaches, which is also when they will have the opportunity to choose, approve or reject the Humboldt Cannabis Reform Initiative (HCRI) which will appear as Measure A on the upcoming ballot. If approved, it would severely hinder local growers by banning them from making any changes to their farms. A report analyzing the HCRI was prepared for Humboldt County Board of Supervisors by the Humboldt County Planning Department in March 2023, explaining the harms of such a measure. “HCRI has been written to effectively discourage existing permit holders from modifying their permits in any way,” the report stated. “This includes adding infrastructure intended for environmental protections or modification of activities or site configuration to adapt to the evolving industry. These restrictions affect the smallest of farms permitted in Humboldt County to the largest cultivation sites.” 

More recently, former Board of Supervisors member Mark Lovelace, who has spent the past seven years advising other California counties and cities on cannabis regulations, wrote an op-ed for Times Standard urging voters to vote no on Measure A. “Based on my professional analysis, I believe that Measure A will deal a devastating blow to the small cannabis businesses it purports to want to help,” Lovelace wrote. “The measure will impose an unrealistically small limit on the size of any new cannabis farms and will deny even the smallest ‘craft’ farmers any opportunity to grow or adapt their operations within Humboldt County. With cannabis prices continuing to fall, small farmers will be assured of making less money every year until they are no longer viable.”

Lovelace described the measure as “grossly uninformed and demonstrates a deep lack of understanding of the cannabis industry and basic economics.” Measure A cites any grow larger than 10,000 square feet (which he describes as slightly larger than the average suburban lot), is a “large grow.” Additionally, the average size of all licensed Californian cultivator lots are more than 27,000 square feet, 93 cultivators are larger than 100,000 square feet, and nine include more than one million square feet.

In addition to other important points of defense of local cannabis growers, Lovelace summarizes the effect that Measure A may have on small cultivators. “Measure A would put Humboldt County’s small cannabis farms at an extreme disadvantage against large growers elsewhere in the state, rendering them largely unviable in an increasingly competitive industry. I urge Humboldt County’s voters to vote NO on Measure A,” Lovelace concluded.