The Clorox website has instructions on how to properly purify water with clorox bleach.
https://www.clorox.com/dr-laundry/disaster-preparedness-purifying-water/A bottle of Clorox should be part of every good disaster preparedness kit.
I keep smaller bottles of clorox in my tornado BOB, fire BOB, riot BOB, national insurrection BOB, and especially the zombie apocalypse BOB.