My recommendation if you are going to finish would involve adding french drain and sump pump, sealing walls with dryloc, then 2" XPS which acts as the vapor barrier, before framing and finishing. 

Since they are often located in residential neighborhoods, they can pose significant toxic tort claims. even if groundwater is not used for drinking purposes, vapors can migrate into homes.

Makes me laugh when people like Harry Dent predict a 80% stock market crash and 50% real estate crash (whatever that means), the money will just VAPORIZE lolI'm hoping for a 10-20% pullback in some markets, if we are lucky.

It's whatever is stipulated in the contract.Generally one company does it only but who pays for it seller/buyer or both and by what percentage each covers if it is both is negotiable.The contract can also stipulate which title company is used.I hope your buyer is having an Phase 1 report,vapor intrusion,site inspection,and cost reserve stable completed on the property as part of the due diligence.All of those items run about 3,500 to 4,000 total and can be completed by the inspector.

You need to know, IMO, every piece of suctural and trim elements used in home construction, from the ridge cap to the vapor barier layed under the foundation.

It can be used as a liquid or a vapor. 

Brandon,I would think your exterior wall assembly probably has cedar shakes over some sort of sheathing (plywood or osb) and vapor barrier such as tyvek or felt paper and maybe even rigid insulation.

Many are interlocking and float over a vapor and moisture barrier.

Removed and redid the ceiling drywall and vapor barrier.

Don't believe me, check this out from energy.gov http://energy.gov/energysaver/articles/moisture-controlA poly vapor barrier can help in these areas as well, again as long as you tightly seal the area - around doors, windows, outlets, etc.