Vic Mensa is making the most of his co-headlining festival in Ghana this week -- he's also leading the charge on a project to bring clean water to 3 villages there!!!

Vic tells TMZ Hip Hop he was moved after seeing the desolate living conditions, including contaminated water, firsthand … and partnered with his father, a Ghana native, to launch their initiative.

The Chicago-born rapper says, "We're building 3 boreholes in different communities in Ghana to provide clean drinking water; the first being the Asokore Zongo in Koforidua where my family lives, which is already built."

Vic adds, "The other locations are a nearby community called Effiduase and then our ancestral village in the Volta Region, Amedzofe. Most people in communities like this in Ghana experience constant waterborne diseases."

We’re told Koforidua is home to around 200k people, Effiduase is estimated at 20k people and Amedzofe has a population of around 6k -- so, the project will make a significant contribution to the health and welfare of the region.

Barring any hiccups, drilling for the boreholes is said to take 3-4 weeks and includes 10-15 days of on-site drilling, followed by pipework and cable installations.

All the operations appear to be first class … water will actually be tested in a lab prior to human consumption, and we’re told the boreholes cost $45k to complete.

Vic will have his hands full pulling double duty, too. He’s slated to perform with Chance The Rapper, Erykah Badu and more on Saturday for the Black Star Line Festival ... which sounds like fun.

Dave Chappelle’s already having a ball in Ghana … and that was just at the airport!