If you want to keep it simple, don't even bother with filtered water and just drink out of the tap. It is safe in the developed world. If you are concerned about germs, which can get through the filter anyway, you should boil the water instead.
I dont trust regulators and have a five stage reverse under the sink filter. Result? In the last five years in my little section of the midwest:
- I've dodged Pb poisoning when my local water authority switched corrosion inhibitors (note, this is after Flint MI)
- I've dodged vinyl chloride poisoning from the Palestine OH fire that Federal regulators pretended was a nothing burger until dead cows started showing up everywhere.
Not to mention the countless times the lines are fixed and the water comes out brown (this is "safe" because it's iron oxide. Except it is only mostly iron oxide plus all the crud that has caked onto the pipes.)
Best case scenario I trust the regulators. Even then F- ups happen and Id rather have a filter I keep myself.