Narrative:

On takeoff roll at 80 KT call out; first officer's asi read 80 KIAS and captain's read 70 KIAS with IAS disagree warning illuminated. Takeoff was aborted; first officer's asi read 94 KIAS and captain's read 83 KIAS. Rejected takeoff[autobrake] did not activate. ATC advised and aircraft exited runway and received clearance to taxi back to ramp. Per maintenance; there was some water in the pitot static system. A drain valve was not in the proper locked position. This was a maintenance issue.

Related reports:

Google
 

Original NASA ASRS Text

Title: B737 Captain reports rejecting a takeoff due airspeed differences between Captain and First Officer airspeed indicators. RTO did not activate.

Narrative: On takeoff roll at 80 KT call out; First Officer's ASI read 80 KIAS and Captain's read 70 KIAS with IAS Disagree warning illuminated. Takeoff was aborted; First Officer's ASI read 94 KIAS and Captain's read 83 KIAS. RTO[autobrake] did not activate. ATC advised and aircraft exited runway and received clearance to taxi back to ramp. Per Maintenance; there was some water in the pitot static system. A drain valve was not in the proper locked position. This was a maintenance issue.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.