If water were a powder, you could add a solvent to it to make it a liquid again. The most common solvent for water is, of course, water itself. You would simply add the water powder to a container of liquid water and stir until it dissolves. Other solvents that can dissolve water powder include ethanol and methanol, but these are not as commonly used as water.

It is important to note that this scenario is purely hypothetical and does not reflect the properties of water in the real world. Water exists as a liquid at standard temperature and pressure and cannot be transformed into a powder form.