Nevada County authorities served 21 search warrants across Grass Valley, Nevada City, Penn Valley and North San Juan this week, arresting nine people at six properties and eradicating nearly 5,000 illegal cannabis plants along with 1,801.4 pounds of processed cannabis. Detectives also uncovered white powder suspected to be methamphetamine, psilocybin mushrooms and LSD tablets at two Nevada City properties, along with an unregistered pesticide imported from China.
The operation, described by the Nevada County Sheriff's Office as part of an ongoing joint-agency collaboration with the California Department of Fish and Wildlife, broke down into eight properties in Grass Valley, 11 in Nevada City, one in Penn Valley and one in North San Juan. The Nevada County Sheriff's Office Special Investigation Unit and CDFW led the effort, with assistance from the Yuba County Sheriff's Office, the EPIC Task Force, the State Water Resources Control Board, Nevada County Environmental Health and Nevada County Cannabis Compliance. Investigators say the searched properties showed signs of water pollution, environmental destruction, trash, dangerous pesticides and evidence of additional drug activity.
Arrests stemming from the sweep included charges for illegal cannabis cultivation, controlled-substance possession, cannabis possession for sale, controlled-substance manufacturing or distribution, cannabis excise-tax evasion, Fish and Game Code violations, Water Code violations, and committing a felony while armed with a firearm. One Nevada City property contained numerous firearms, including one that was loaded, according to the sheriff's office.
Banned Chinese Pesticide Found at North San Juan Site
The North San Juan property was found to be using illegal pesticides imported from China, according to the sheriff's office post. An attached product label recovered at the scene identifies the pesticide as Fumeili, a smoke-agent formulation listing 10 percent active ingredient content and describing the product as low toxicity.
The active ingredient, procymidone, is a dicarboximide fungicide that is not registered or approved for agricultural use in the United States by the Environmental Protection Agency because of potential health and environmental risks, according to the California Department of Cannabis Control. Chinese-labeled pesticide smoke agents found at illegal California grows typically consist of sawdust mixtures saturated with unapproved toxic chemicals that release dangerous gases when ignited, per findings cited by the Siskiyou County Board of Supervisors.
Part of a Broader, Grant-Funded Crackdown
The 21-property sweep is the latest in a string of seasonal operations targeting illegal grows in Nevada County. In April and May, the sheriff's office and CDFW served four search warrants in Grass Valley and Nevada City, eradicating 14,619 cannabis plants and seizing 94 pounds of processed cannabis along with 1.3 pounds of psychedelic mushrooms, as reported by ABC10. In September and October 2025, a similar joint operation across eight properties destroyed 5,000 plants and seized 1,500 pounds of processed cannabis, leading to criminal charges against seven people, as reported by CBS News.
On July 1, the Nevada County Sheriff's Office and the Nevada County Community Development Agency were awarded a Proposition 64 Public Health and Safety Grant to fund local cannabis enforcement, public health initiatives and safety compliance programs, according to the sheriff's office. That funding helps explain how the county sustains repeated, resource-intensive operations like this one. The EPIC Task Force that assisted deputies was established in October 2022 by California Attorney General Rob Bonta to expand the state's historical Campaign Against Marijuana Planting into a year-round effort targeting environmental damage and labor exploitation tied to illegal grows.
Environmental Charges Carry Aggravated Felony Weight
Under California Health and Safety Code Section 11358(d)(3), illegal cannabis cultivation charges are elevated to aggravated felonies when accompanied by environmental degradation, including violations of Fish and Game Code Sections 5650, covering water pollution, and 1602, covering unauthorized streambed alteration, according to YubaNet. Joint-agency officials emphasized that the searched properties were suspected of operating illegal cannabis cultivation while polluting California waterways and watersheds, threatening natural resources and public safety.
The Nevada County case is a small piece of a much larger statewide push. Between late 2022 and December 2025, California's Unified Cannabis Enforcement Task Force served more than 750 search warrants across 29 counties, eradicating 1.3 million illegal plants and seizing over 841,000 pounds of illicit cannabis valued at $1.3 billion, according to the California Department of Cannabis Control.
Legal Cannabis Rules Stand in Contrast
The illegal grows targeted this week operate far outside the tightly regulated framework that governs legal cannabis businesses in the county. In November 2024, the Nevada County Board of Supervisors updated the county's Commercial Cannabis Cultivation Ordinance to allow up to two storefront dispensaries in unincorporated areas, specifically Soda Springs and North San Juan, while requiring locally grown sourcing for certain commercial retail sales, per YubaNet. In Grass Valley, where eight of the 21 warrants were served, municipal regulations limit commercial dispensaries to a maximum of two permits citywide, capped at one permit per 7,500 residents, according to the City of Grass Valley.
What happens next for the nine people arrested remains unclear, as prosecution outcomes have not yet been reported. The long-term environmental remediation needed at the contaminated rural properties is also an open question. The sheriff's office is encouraging community members to report suspected illegal cannabis or other illegal drug activity to its Special Investigation Unit, either through anonymous online tips or by calling (530) 265-1471.
This week's operation follows a run of Nevada County drug enforcement stories that Hoodline has tracked in Grass Valley over the past year, including narcotics warrants and an armed robbery attempt at a legal cannabis farm.
