Inspected for leak. Opened drywall to inspect plumbing in the area of staining. Plumbing in the ceiling appears to be ok. Found a leak on the drain of the master lavatory. Replaced leaking section of pvc and installed a new trap. Tested with water for 15 minutes. No leaks found. Suggest leaving the ceiling open for a while to confirm there are no leaks. Not responsible for drywall repair. Thank you for choosing T.E. Certified.