This command enables and disables (toggles) the visibility of water. Note that when you are submerged in (under) water, water will still be rendered.
tws
tws
If water is visible, this command will hide water. If this setting has already been activated and water is hidden, executing the above command will make water visible again.
ToggleWaterSystem
ToggleWaterSystem is simply a longer version (alias) of the TWS command - it has the exact same function.