The RH hot cell lab active sump high level sensor was tested as part of the yearly scheduled inspection.  High water level was simulated by tilting the sensor sideways with a long pole sample scoop.  The Main Control Room and Hua Yang from Nuclear Medicine were notified before the test.  The alarm sounded as expected, and a message was received in the main control room.  This is a latching signal, so a Control Room operator will go to the MHESA RCR lab to reset the alarm.  The water level was approximately 12" below the high level sensor, so the sump may need to be sampled and emptied soon.