I will say, most cabins are on well water, which can be tricky - the water can be very mineral-y and, depending on the well and conditions, can have an odor (sulfur) or some color.  

Plus the washer gasket (although replaceable) is a mold/odor haven that is very nasty to swap out & everyone complains about it.

Never been faced with a huge odor issue but from what I've read on other posts, the ozone machine is the way to go after a good clean

Know what to look for in terms of evidence.... drug paraphernalia, odors, residue on walls and in furnace filters, etc.What did they say when you served them the prior notices to comply?

What exactly is the odor... rubber burning (e.g., the aforementioned drum belt), an electrical odor (e.g., motor failing) or that classic, dryer exhaust smell of hot, humid air and heated cotton and synthetics?

It looked great, but there was a little bit of a damp/musty odor in the home.

I got there as they were finishing up but couldn't go in because of the odor.

If it has a bad odor, it is probably contaminated.Joe makes a good point on the expansion tank as well.

having been in the business for a few years, no ceiling, no floors, mold and bad odors no longer phase me, it norm.

Single story with concrete slab...maybe that is better although i have never had to get rid of cat urine odor out of either material.