Is it possible to take asteroids and use for them to for our Earth' s fresh water supply?

After reading comments on a href="http://finance.yahoo.com/real-estate/article/111186/the-ten-biggest-american-cities-that-are-running-out-of-water."http://finance.yahoo.com/real-estate/art…/a I thought of an event that could help our fresh water supply I mean did our fresh water came from giant asteroids or not? Can we use that to sustain drows everywhere and such or I crazy for thinking such an event?