You should get your water tested. While your water district report is a fine baseline, it won’t tell you about things like lead scale in your home’s feed line that are localized to your plumbing.

I had this done and learned my home originally had a lead feeder line from the mains that was replaced 30 years ago, but coated the pipes in lead scale. Now we use a 6 stage RO system.

Nine Inch Nails would be perfect.