In Far Cry 4 the only indication you are drowning is a muffled sound like suffocating. No visual clues. I turned on subtitles to see if they added the sound by words but no change.
Accessibility for hearing impairments is often focussed solely on subtitles – ensuring that speech can be understood. However games are not solely based on speech, there is a greater requirement in games than in other media on being able to understand audio cues.
Many sounds are purely aesthetic (which can also be represented visually), but the most important ones are those which are essential to gameplay.
Try playing the game on mute. If there’s any sound missing that causes you difficultly playing, find a way to represent it visually. This may be through additional optional subtitles (when representing something other than speech, they are known as ‘closed captions’), or through graphical indications in the environment, on your avatar, or in UI.
Best practice example: Gears of War 3