Whats the PH of this system?

A metal plating waste contains 20 mg/L of Cu2+ and it is desired to add NaOH (which completely dissociates to Na+ and OH-) to precipitate all but 0.5 mg/L of the copper. To what concentration in moles/liter must the hydroxide concentration ([OH-]) be raised to accomplish this? Ksp for Cu(OH)2 is 2x10-19. What is the pH of this system?