We spoke with Van Butsic and Ted Grantham, co-directors of UC Berkeley’s Cannabis Research Center and adjunct fellows at the PPIC Water Policy Center, to better understand how cannabis cultivation affects the state’s water.
To give you a sense of scale, we estimate that Humboldt and Mendocino counties alone had around 15,000 illegal farms in 2018.
Ted Grantham: Many legacy farms that were in operation prior to state legalization are still present, especially in Mendocino, Humboldt, and Trinity counties—the so-called Emerald Triangle.
We see more variability in cannabis water use than other crops, partly because cannabis has avoided the standardization of production methods that we find in large-scale agriculture.
We are concerned about cannabis water use because many cannabis farms are in remote upper watersheds that support sensitive species.
We’ve heard from local officials that there’s been a dramatic increase in production in San Bernardino County, where cannabis cultivation is prohibited, and there are concerns over increased water withdrawals from stressed aquifers.
But, so far, studies haven’t detected high levels of contaminants in streams, and the effects from cultivation appear to be fairly localized.
TG: Many growers actually support environmental regulations, although they also report that requirements are often difficult and expensive to meet.