Get your water tested in California.

California’s list has 145 labs certified to test drinking water: 108 in California and 37 in other states. It also names 156 water utilities’ in-house labs, left out here because they test only their own systems’ water. 2 of the labs here are named for a water utility and may test only its own water, so they come last.

Certification is test by test, so check that a lab is certified for what you want tested, and call first: it will say which bottles to use and how soon the sample has to arrive.