"Colorado's state laws legalizing marijuana do not limit how much marijuana can be grown within a private residence. Further, there is no mechanism at the state-level to document or regulate home grows, even large ones. This has led to a proliferation of large-scale marijuana grow operations in hundreds of homes throughout the state. Much of the marijuana produced in large home grows is shipped out of Colorado and sold in markets where it commands a high price. Although growing a large number of marijuana plants within private residences can fall within the parameters of state law, it presents potential risk to the occupants, homeowners, and neighbors of these residences, as well as to first responders who are called to them. Marijuana grows often cause extensive damage to the houses where they are maintained and are increasingly the causes of house fires, blown electrical transformers, and environmental damage. Much like the 'meth houses' of the 1990s, many of these homes may ultimately be rendered uninhabitable."
DEA-DEN-DIR-041-16; Drug Enforcement Administration Denver Division Intelligence Report 041-16
Drug Enforcement Administration: https://www.dea.gov/