The illicit and illegal use of water to grow marijuana is an environmental problem that has plagued the recently legalized crop for decades. Because growing marijuana has consistently been a more visible crime than theft and diversion of the water used, the industry’s environmental crimes have largely been ignored until recently. The recent legalization of marijuana in California included new environmental regulations aimed at curbing the environmental damage done by marijuana farmers; however, these reforms may have the converse effect of encouraging marijuana farmers’ continued illicit water use. This Article explores the history of marijuana legislation, why water use rights are such a central issue, and the environmental damage that has been done to California watersheds. It analyzes how the trend toward legalization could potentially encourage marijuana farmers to continue illegal water use practices, considers the means by which California regulators are encouraging marijuana farmers to comply with water regulations, and recommends additional methods to encourage compliance, such as shorter application times, a tiered system that incentivizes complying with current legislation, and educational programs aimed at both educating farmers on the advantages of compliance and changing their mindset around water use.