concrete slab moisture limits?

[Joanne Smith]

Hi,

I understand there are codes regarding concrete slabs (below grade). Are there exceptions to water proofing/damn proofing, even if the living space is right on top of it (like basement level apt or condo)?

My question is if it's ever OK for the slab to be wet on the surface (and how much is too wet) if there is a floor (living space) directly above it.

[Markus Keller]

Assuming you are using a fairly general definition of wet, i.e. the concrete looks or feels wet to the touch, then the answer is NO, its not acceptable for the slab to be wet. A wet slab would essentially make the space minimal storage space. Putting any type of finished flooring on the slab would end up being a problem over time. Using the space as a rec room or something could bring about health issues. Under your outline the space is pretty much un-uesable.
So you hired a contractor and now have problems and are thinking of suing the guy?
If a basement slab is wet there's a reason. The concrete itself will eventually cure out and be essentially dry. As concrete the moisture level varies but it shouldn't be at a 'wet' stage under normal living circumstances.
If this is a new construction build then it will be pretty normal for the concrete to look wet for quite some time. Around here 3-9 months is fairly normal for the wet look (darker grey) and damp concrete smell to be completely gone; depends on conditions, amount, time of year, etc of course. I don't know what your climate or ground situation is like in DC so ... time will vary.
Another possibility is the poured the slab without installing a membrane and you have high ground water levels in your area.
If this is old concrete then there is a water intrusion source. Bad grading, bad downspout to ground connections, bad sewer, something.
As far as Code exceptions, that's possible but unlikely if you are talking about residential occupancy space. I don't know why you would want an exception.
If you are looking for ammo to sue the contractor, then you are asking the wrong questions. I suggest you document moisture readings for the concrete and hire an inspector.