The media and the Internet are full of stuff written about grow ops (marijuana growing operations) that have been set up inside residential homes. In fact, the volume of information (hype) about grow ops is one of the issues. Essentially, if you are stuck with a piece of property that was recently being used as a grow op, you have some significant problems to deal with. Unfortunately, if you have bought a home that was EVER used as a grow op, then you still have a significant problem. And the worst case might be if you own a home that has been listed as a grow op when it either wasn't one... or it was a very small scale operation that didn't affect the infrastructure of the house... you STILL have a significant problem. By the way, any landlord is exposed to the risk of becoming the owner of a grow op through no real fault of their own.
In order to grow marijuana consistently, it takes light and water -- lots of each. The lights mean a big power drain, and high electricity use is one of the clues that cops use to find grow ops in seemingly innocent neighborhoods. But the growers tap into their next-door neighbor's power and use other tricks to mask the additional hydro consumption. A bloom on a heat sensing camera is another clue: all those lights keeping the plants warm also warm up the house.
Marijuana apparently thrives in a warm moist environment. Unfortunately, so does mold. Mold grows even after the source of moisture and warmth has been reduced or eliminated. In really bad cases, pesticides have also contaminated the environment, seeping into walls and floors. That's why the saying "once a grow op always a grow op" has come into use. Most major banks have standing policies not to issue mortgages against former grow ops and insurance companies often refuse to insure them.
The issue is that, as with anything, there are different variables that a blanket statement or policy simply doesn't take into account. A "list" or "registry" also doesn't take the individual circumstances into account: your property is either on the list or it's not. It either was a grow op once or it wasn't. The media hype around the effects of mold are also driving a serious fear, comparable to the UFFI scare several years ago. Mold should not be taken lightly, but it CAN be addressed. And with a good mortgage or insurance broker, you may find a smaller lender or insurance company willing to deal with a grow op.
My advice to my clients after seeing the incredible and lasting issues attached to a grow op, no matter what the circumstances, is to walk (or run) away if you're the buyer. If you're trying to sell a property that was once a grow op, properly disclose the circumstances to any potential buyer (right on the MLS listing for all to see) and be ready to show that the problem has been fully addressed. Sadly, that means you're likely losing money on the deal.