As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TOILET FLUSH SYSTEM DOES NOT FLUSH AFT LH LAV D FOUND PORTABLE WATER TANK DRAIN VALVE NO FULLY CLOSED, FULLY SECURED VALVE CLOSED. SINGLED OUT PORTABLE WATER TANK AIR SUPPLY (APU AND COMPRESSOR). EACH SUPPLIED NECESSARY PRESSURE TO OPERATE LAV A TOILET FLUSH WITH WATER. OK FOR CONTIUNED SERVICE.