Mostly, yes. Some of it is used for protecting the structure (ablative armor, essentially). But that requires much less water than is actually used. This is why

Mostly, yes. Some of it is used for protecting the structure (ablative armor, essentially). But that requires much less water than is actually used. This is why Sea Launch's launch platform also had a water deluge system. They're far enough out that the only people that can really hear it are the control ship, but they have the deluge to help keep the exhaust from scorching the launcher. Similarly, the Saturn V MLP had "rainbirds" to wet it down, even though the vast majority of the water used was down the exhaust trench for sound suppression.