What was found
AIRSPEED UNRELIABLE PASSING 12000 FEET. CHECKLIST DETERMINED BAD INFORMATION ON FIRST OFFICER SIDE. SELECTED CADC 1 ON FO SIDE AND INDICATIONS MATCHED. EMERGENCY DECLARED. INSPECTED FO PITOT TUBE AND FOUND THAT THE DRAIN HOLES WERE OBSTRUCTED. CLEARED DRAIN HOLES AND A GOOD AMOUNT OF WATER CAME OUT OF THEM. PURGED THE FO PITOT SYSTEM AS REQUIRED AND ALSO CHECKED FOR WATER IN THE PITOT STATIC LINES WHERE INDICATOR FLOAT IS LOCATED. MORE WATER CAME OUT OF THE SYSTEMWHEN PURGING , BUT THERE WAS NO MOISTURE IN PITOT STATIC SYSTEM DRAINS WHERE FLOAT BALLS ARE LOCATED. PERFORMED SUCCESSFUL FO PITOT STATIC SYSTEM LEA TEST. REF AMM 34-11-00-2. OK FOR SERVICE.