Is it recommended to take benefiber with water? if not, with what?

Any liquid: Water's fine. But other liquids are okay too (most any liquid you drink will be >90% water anyway).

Fiber: Yes, you should take fiber with water. Make sure you take adequate amount of water. If not taking adequate amount of water with fiber, this will actually worsen your constipation. Rule of thumb: one table spoon in 8 oz of water. Don't take high volume of fiber at the start, this can cause excessive bloating. Titrate from low to tolerated.