Some of the more common metals or other substances removed via precipitation include:

1) Aluminum

2) Arsenic

3) Barium

4) Cadmium

5) Calcium

6) Trivalent chromium

7) Hexavelent chromium

8) Copper

9) Iron

10) Lead

11) Magnesium

12) Manganese

13) Mercury

14) Nickel

15) Selenium

16) Zinc