Most drug stash houses are rental homes.
Stash house caretakers prefer homes with attached garage.
Yard is unkempt, although sometimes they will send someone to clean it up so as to not draw attention.
There is usually little, if any, furniture in the home.
Stash house occupants tend to keep to themselves and they will not normally be visible on a daily basis.
If the occupants are actually living at the stash house, they will not appear to hold a regular job, or have a "normal" pattern of lifestyle.
Different types of vehicles, especially vans and pickup trucks will enter and exit the garage at different hours of the day or night. (Quite often they prefer to work in the nighttime or early morning hours)
The vehicles arriving at the stash house will have different license plates on them, including, Texas, New Mexico, Mexico and paper "buyer" or "dealer" tags. They may also use these license plates interchangeably with all of the vehicles.
You may not see anyone at the stash house for several days or weeks and then there will be a lot of activity (as described above) at the house.
There may be an accumulation of advertisement material on the front door and/or trash in the home or yard.
NOTE: The presence of some or all of the indicators does not mean that the person is violating any law. The lack of "normalcy" is the best indicator that something is not right. Please call if you have any suspicions.