Marijuana Grow Operations

by Nick Gromicko, CMI®


A marijuana grow operation is the cultivation of marijuana, sometimes illegally, for the purpose of sale and distribution. Indoor grow operations can be found in places such as houses, apartments, commercial businesses and abandoned factories. There are thousands of illegal marijuana growers in the United States, but the problem is considerably more serious in Canada.

Facts and Trends

  • In Canada, marijuana grow operations are becoming so common that many police departments have given up trying to fight them. From 1994 to 2004, the number of marijuana cultivation offenses more than doubled, and Canadian law enforcement estimates that there are currently 50,000 grow operations in the country.
  • In the Canadian province of British Columbia, marijuana growth generates an estimated $7 billion annually.
  • Most of the marijuana grown in Canada will eventually be sold in the United States, where it is worth more.
  • Grow operations can be found in any type of house and community. Homes with grow operations are not necessarily cheap rentals or suspicious-looking, crumbling old homes in ramshackle communities. Newer homes in upscale communities are increasingly used to hide grow operations. Marijuana cultivation can be so lucrative that the entire cost of the house is paid for in a short period of time.
  • Although it may seem like a serious risk for a current grower to hire an inspector to examine their home, it does happen, if rarely. Many grow operations are not temporary, and the growers have an otherwise normal household. Drug dealers need their homes to be inspected, too.

Why should inspectors care about grow operations?

Learning about the typical problems created by grow operations will enable inspectors to recognize defects. If an inspector can recognize that water damage, for instance, was a byproduct of a former grow operation, they may waste less time in the attic searching for the source of water leaks.

Common indications of marijuana grow operations:

  • heat and humidity. Water that is fed to plants will transpire and evaporate from the containers into the surrounding air. Cannabis plants also require warmth. Excess water vapor and high temperatures can lead to the following defective conditions:
    • water damage. Water damage caused by grow operations will likely appear uniform throughout the room, unlike the generally localized damage caused by water leaks. Even normal house plants can create enough water vapor to damage shingles, and a large marijuana grow operation may cause a considerable amount of water damage.           
    • large mold accumulations. Mold grows fast in humid environments. It can be a health concern, as well as a source of structural decay.
    • lack of snow on roof in winter due to high temperatures indoors because of the use of grow lights, etc. Fish hooks used to penetrate power lines and steal electricity
    • unusually high amounts of steam coming from vents in winter.
  • improper electrical connections. Grow operations, even relatively small ones, require an enormous amount of electricity for lighting. Some utility companies will report suspiciously high levels of consumption to police. In order to avoid this possibility, growers will often illegally bypass the electric meter to gain access to electricity without any record of the theft. They accomplish this by tapping electricity from the power lines before they reach the meter. In the accompanying photo, Romex cable has been attached to large fish hooks that were used to tap utility lines at the pole and illegally deviate current into the home. Inspectors may encounter other types of inventive yet improper or dangerous electrical connections.
  • high electricity bills. Energy auditors, many of whom are inspectors, may come across a house that uses far more energy than seems necessary. Inspectors may also be given utility bill information from energy auditors.  

Other indications for InterNACHI inspectors and neighbors:

  • skunky marijuana odor. Other odors may also be apparent, such as those from mothballs, air fresheners or chlorine, which are used in an attempt to mask the marijuana smell;
  • unusual garbage strewn across lawn. Items used for growing marijuana, such as wiring, PVC piping and nutrient containers, may be discarded and left around the house;
  • humming sound. electrical equipment used for the growing operation can create sounds similar to transformers;
  • windows covered in dark plastic or newspaper;
  • perpetually illuminated rooms;
  • extra security, such as guard dogs and fences.
In summary, inspectors may encounter unsafe or defective conditions caused by marijuana grow operations.