Before you'd want to consider using your water, you'd want to run a complete test on it. Even if it tests alright, and some well water can be as good as city water. You'd still be better off using ro water. Plus, atleast than you'd "know" what you're putting in your tank. You should be able to pick up ro water for really cheap at lfs's or even supermarkets. You can wait, or hold off indefinately on ever purchasing your own ro unit.