Public water/sewer.Main Floor and 2nd floor have no odor, no mold.  

When looking at investment property, pet odors smell like money.I bought one of these a few years back and was prepared for chemical warfare. 

Basement was gutted and drywall and ceiling tiles were added and painted.The garage had a strange odor and the floor was sticky from old carpet so the floors were epoxy painted.

Still in due diligence and have alerted buyers agent that we will be going back to seller with a discount on the offer to take into account the odor remediation.

@Erik Whiting  over the course of the decades working with clients another very easy way to determine the status of your renter is to look at their car.. if its a pig sti  so is the house 90% of the time I work out of my car a lot so its probably a little more messy than some.. but you know what I mean.. you can just tell.. and I really like  the ODOR  thought process you can smell folks that are un tidy they have a certain odor to their cloths.. as one who has worked in the distressed space for so many years .. you just know it..

This creates a vapor barrier that prevents humidity and odor from entering the interior of the house.  

Add fresh flowers and make sure the duplex smells clean, since a bad odor will often turn buyers away almost immediately.

The tenant that took the photo says it was odor that made her look behind the building.

We purchase 3, one had puppies and we kept all 13 dogs because we hated to think that someone would not love them as much as us.I've had tenants who brought in dogs and it cost me thousands of dollars to try to get rid of the dog odor.

However, nuisances which violate tenants rights of quiet enjoyment, and interfere with the comfort, convenience, or health of an occupant include foul odors, noxious gases, and smoke...