I am in the middle of closing a condo and just realized that there is a hard, raise line in the wall. It is not near a window. Is this a major concern/fix?
Cracks in drywall are typically found around windows and door openings. In this case there the crack does not appear to be associated with any opening and there is an absence of staining. However there could be a pipe that is not properly connected/glued/clamped in the wall cavity and could leak only when drainage occurs from something like a dishwasher or sink above. And this defect could have been painted over to hide the original subsurface stain.
You will need to contact a qualified general contractor and notify your builder that the wall needs to be opened up. Further investigation is required into the wall cavity and the possibility of an improperly connected drain and/or leak.
Hope this help and please let me know what the final result is as others may be experiencing the same problem.
James F. Ellacott RHI