Knowing that the water on a launch is used for both noise suppression and surface cooling, do they recover the water that isn’t evaporated by the launch to use again? And if they do, how so?
For the shuttle program, the water was not recovered.
The water that was not vaporized ran through concrete channels and was collected in two holding ponds.
(NASA photo, annotations mine).
The water was later pumped out and allowed to soak into the sandy soil.
The discharge of deluge and firex water (during the launch of each Space Shuttle) resulted in the collection of water in two holding ponds, located northeast and northwest of the pad flame trench. Unknown volumes of water have splashed out and onto the field directly north of the flame trench or were vaporized into the launch cloud....
....Analytical values for selected parameters of concern for the northeast holding pond, representative of both ponds, indicated that levels of chlorides, aluminum, iron, and zinc here present in substantial quantities (table 2-2). This calculation is important because this water was later pumped from the ponds onto the field and, therefore, was subjected to leaching and could pose a problem to the ground water supply.
From SPACE SHUTTLE ENVIRONMENTAL EFFECTS: The First Five Flights, emphasis mine