Here is Environmental Working Group’s (EWG’s) data on tap water in your area. Once you click on the link, you can put your zip code in and will be brought to a page where you can choose your particular water system. If you have contaminants listed above health guidelines, these will be listed. There will also be a place where your can find the possible sources for the contaminants.
I did click on the database, entered my zip code and Sonoma County came up. Glad I don’t live in Santa Rosa, that water looks so nasty I wonder about washing in it?