This study examines feedback from automated reports and a participant survey concerning implementation of an emergency notification system (ENS) in a multi-agency functional flood exercise hosted by Maricopa County Department of Emergency Management. Representatives from nearly two dozen agencies were present. Emergency notifications through the ENS were reported after the exercise to have generally been useful in terms of keeping agencies appropriately informed in a timely manner. Most exercise users indicated that they were pleased overall with the results of using the ENS. One aspect of the experience that they noted having appreciated was the opportunity to replay messages if they wished to do so. However, technical problems with use of the ENS did exist. For example, text-to-speech (TTS) rendering in some instances produced messages with poor intelligibility, confirming the need for care in choosing well-functioning text-to-speech software and in crafting TTS messages appropriately for TTS rendering. Some messages going to voice mail during the exercise were clipped, such that recipients could not hear the entire message, a flaw. While nearly all exercise players received emergency notifications from the ENS via one or more communication devices, less than half of the total messages were listened to during the timeframe of the exercise. This confirmed the wisdom of keeping messages sent through different communication systems and channels consistent, because not all contacts listen to all messages on all receiving devices. Exercise players indicated a need for (i) notification messages to be crafted to be short, concise and easy to understand, (ii) the messages to have a date and time associated with them, and (iii) the messages to contain geographic locations, information on emergency impacts, and other intelligence needed to allow users to make appropriate responses.