Watershed scientists have been exploring how the water use footprint of licensed cannabis compares to unlicensed cannabis water demand, residential water demand, and available stream flow.

The Berkeley Cannabis Research Center in the College of Environmental Science Policy & Management at UC Berkeley publicized their latest science brief, “Water Use: Cannabis in Context,” this month ahead of the upcoming Measure A ballot.

After reviewing data from Humboldt and Mendocino County watersheds, their findings and recommendations are as follows:

  • Water use by cannabis farms represents a small fraction (<1%) of natural surface water supplies in most watersheds
  • The majority of water demand for cannabis cultivation comes from unlicensed farms rather than licensed farms, particularly during the dry season (June – September)
  • Water storage by cannabis farms shifts the timing of water withdrawals away from the dry season, and has been an effective management practice for reducing impacts to surface flows
  • Providing incentives for farmers to increase off-stream storage for irrigation is a key strategy for reducing water extraction during the dry season
  • Disincentivizing cannabis farms from participating in the licensed industry will likely only exacerbate impacts to dry season stream flows, as unlicensed farms are less likely to utilize water storage to satisfy dry season irrigation demands