there are certain "supplements" on the market that claim to make your herp more colorful, etc. Steer clear of these. They do nothing and could possibly hurt your cham. There is one that claims "all natural" and contains excess beta carotene (it's what makes carrots orange) to pormote orange and yellow, but too much beta carotene in his system can cause serious vitamin a overload which in turn can cause many problems. So accept him for who/what he is and enjoy him. Depending on species and age he may still be developing his colors
As for water, tap water is OK if you leave it out overnight (can fill gallon bottles) so any chlorine dissipates - that's if you have city water. We have a dug well so no chlorine, but possible heavy metals so I buy the cheapie spring water - even use that for my frog's tank. Distilled water does not contain some trace minerals that he shouldget in his water. So depends where you live. I know some herp keepers set up R/O system (reverse osmosis)