A little Clorox does just fine too. Keeps your undies white as well.
If you only knew what was in your municipal water supply.........
Sometimes I think there is too much 'to do' about water. back when I was an Eagle Scout we just boiled water if we thought it might cause the poops or worse. I drank out of many streams when on outings and never got ill...and we used compasses not GPS and carried everything in rigid framed backpacks (I still have my Kelty btw). Back then, we didn't know about cysts or microorganisims but I'm sure they were there. Probably been there for a thousand years. We used sodium hypochlorite (bleach) and I still do.
IMO, nothing beats a cold drink from a mountainside stream or spring.
I tend to pay attention to locals when it comes to water. Last fall in NM, our guide told us not to drink the water (not that there was much anywhere). I had no issue heeding that. I figured he knew. What there was, was nasty stuff anyway.