Future and 21 Savage Rent Out Atlanta Water Park for 'Hood Day'

Future, 21 Savage and fellow Atlanta rapper Big Bank Black gave back to their community in the funnest way possible ... AND helped everyone stay cool in the process.

The rappers rented out the entire water park at Six Flags White Water in the ATL Wednesday, and seemingly invited everyone from their Zone 6 neighborhood to get some relief from the summer heat at an epic "hood day."

We're told the 3 hip-hop stars dropped around $300k on this year's celebration for Zone 6, which included free food and drinks for everyone. Savage and Big Bank joined in on the good times on the lazy river too.

Other celebs who got wet and wild at the park included Tommie Lee from 'L&HH' and reality star Shekinah Anderson. There was also no shortage of chicken fights and surprise dunking ... 21 Savage even fell victim!!!