BiggerPockets

Hey Melinda,
Some give aways:
1. They're looking real hard at the attic / basement space.
2. They're offering to pay in all cash all the time.
3. They ask if the house is going to be for sale in the near future.
4. They smell like weed / poop :D

You can spot it by:
1. buying a really expensive thermal camera
2. Calling the local gas / electric co to get the current monthly average and compare it to the previous tenants. Grow lights use a lot of wattage (of course they could bypass the meter, or have some generators or something... but usually the meter will spike in use.

The water bill will also go up considerably. Make sure you know how many people are there.

Oh yea, the biggest way to tell is to schedule an inspection and go look!

Cheers,
Mark

Hey Melinda, My parents did a good job raising me, and luckily, as my grandmother so elegantly used to put it "I wasn't born yesterday"

Anyway, IMO - I've fended off about 3 separate cases where I believe this would have been the outcome. I've only been in the biz for 2.5 years, and have show property approximately 100 times.

The most notable experience was this:
Girl and Guy come to look at house.
Girl says "this is my friend, won't be living here"
She is young (20's)
OK so far. Guy does not introduce himself, girl does introduce him either.
I show her the house. They see the house, and they don't seem too interested. We're upstairs they say "This place has an attic right?"
I say yes, as in the add, attic storage. And I take them up (through closet). I go back down. They spend about 5 minutes up there... empty attic... OK, kinda weird, but whatever, maybe they have a lot to store... though they don't even go into the basement. I have another house (they are ONLY interested in SFHs) that is ready same time, I offer to show it, they say OK. We go there and they look around. 1st question. "Where is the attic" Sorry, no attic here. They leave and say "OK, we will think about it." 10 minutes later she calls "I want the one with the attic, I'll pay all cash, I'm a waitress"
Rent = $925
I connected all the dots!

Thermal Cameras are EXPENSIVE
http://www.flir.com/US/

These would have been smaller time fish. Growers operating in McMansions don't live with the product, though they spend great effort making it look like someone does. For these types of things I would want a thermal camera and a SWAT team!

Good luck!!!

A couple of ways to help keep them out:

Do a criminal background search.

Verify that they have a legitimate job that pays them enough to live on. No visible means of support is an automatic rejection.

Check with their current and prior landlord, especially about the condition of the house.

Verify (using the credit report) that they are actually living at the address that they claim. Verify independently of the information they give you, who the owner of that house is.

Verify that they have given notice that they are moving out.

Let all applicants know that you check on the rental frequently. Drug growers are looking for a landlord who won't come around.

On the credit report, they should not have charge accounts, paid up, that are way over what they should be able to afford on the salary that they are declaring. If they are living above their means, that money is coming from somewhere.