As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOST CABIN PRESSURE, DESCENDED TO 10,000 FEET AND RETURNED TO ORD. *S/D* MAINTENANCE DETECTED DOOR 1 RIGHT LEAKING. ALSO, FOUND FWD E & E DRAIN VALVE LEAKING. REPLACED DRAIN VALVE AND REINSTALLED DOOR SEAL AND PERFORMED HULL LEAKAGE CHECK.