Regulation promises mitigation. We assess threats.


Cannabis cultivation can impact the environment by clearing vegetation, diverting water and introducing pollutants. Farms in remote regions also encroach on habitat for sensitive species. Using field study, social surveys, remote sensing and modeling, we investigate how cannabis cultivation affects water, wildlife and watersheds.

What we’ve learned

  • Environmental impacts of cannabis production occur through the use of water, pesticides and energy, land cover change, and the pollution of air and water.
    Wartenberg et al. 2021
  • Since 2000, cannabis production rapidly expanded into undisturbed, sensitive habitat areas. Though farms tend to be small, they cause deforestation and contribute to wildlife habitat fragmentation.
    Wang et al. 2017
  • Early regulations for medicinal marijuana did not prevent siting of cannabis farms in environmentally sensitive locations in northern California. The number of sites on steep slopes or near remote public lands both increased between 2000-2013.
    Butsic et al. 2018
  • Seasonal water use by cannabis farms is influenced by water source. Farms that rely on surface water often divert and store water in the winter for irrigation, whereas farms that rely on groundwater divert water on-demand. Dillis et al. 2020
  • Groundwater well use by cannabis farms is common and likely contributes to streamflow depletion. The majority of permitted cannabis farms use groundwater wells. Models suggest that unpermitted farms do the same, though extraction volumes vary substantially by watershed.
    Dillis et al. 2019 Dillis et al. 2020Dillis et al. 2023
  • Human activity on cannabis farms impact nearby wildlife communities. Wildlife observed on farms differs from surrounding uncultivated areas in southern Oregon, suggesting impacts on ecological communities.
    Parker-Shames et al. 2021

Science and Policy Briefs

Water Use: Cannabis in Context

After reviewing data from Humboldt and Mendocino County watersheds, researchers find that keeping cannabis farms in the licensed market is key for preventing impacts to streams.

Environmental Impacts of Local Cannabis Cultivation Bans

Cultivation bans do not stop cultivation or environmental consequences of farming, and may worsen them.


Related Publications


Dillis, C., Petersen-Rockney, M., Polson, M.

Journal of Environmental Management

Photo of marijuana plant in a grow bag, surrounded by the flames of wildfire


Dillis, C., Butsic, V., Martin, J., Reiman, A., Starrs, G., Grantham, T.

Environmental Research Letters

photograph of a circular lined pond, full of water, on a forested slope


Dillis, C., Butsic, V., Georgakakos, P., Portugal, E., Grantham, T.

Environmental Research Communications

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