Water dripping sound from walls?

is your floor the top floor, or are there stories above your own? usually, water dripping is a bad sign of future expensive repairs. I think you should contact condo management about checking on this. [and do NOT rely on your homeowner's insurance to cover this cost ... it is probably explicitly excluded because yours is a condo and the association is responsible ... well, responsible for them may mean a special assessment to be paid by you.] {Aside: even if there is water leaking from a unit above you, you can not rely on that unit's insurance to cover this cost ... many owners in financial distress cease paying on their homeowner's insurance and, if presented with a major repair bill, will simply walk away from the unit -- and the mortgage holding bank won't pay for this, thus dumping the cost on the association which may well lead to the special assessment I mentioned.}

I will bet that one of your neighbours' toilets is leaking down the drain.  If there is nothing wet, do not worry.  Most condo owner;s responsibility stops at the paint on the wall .  So it is not your problem