One gadget that improves society

One thing I would invent that would improve society would be a machine that turns salt water into fresh water. It would do this by taking salt water and putting it into the machine, and it would then extract the salt from the liquid. It would then purify the water three or four separate times just to make sure that the water is as pure and fresh as possible. This machine would benefit people, because  less than 10% of the water on our planet is fresh water. We (as people) cannot drink salt water, therefore my machine would increase the quantity and supply of fresh water on our planet. Without this machine the human race would drink up the rest of the fresh water, but it would most likely occur over a million years from now. It would mainly help sustain life on earth for billions of years to come.