Sam's Purified Drinking Water Bottles, 20 fl oz, 28 Count

Linked elsewhere, not advocating for Walmart specifically, but these exist absolutely everywhere: https://www.walmart.com/ip/Sam-s-Choice-Purified-Drinking-Water-20-fl-oz-28-Count-Bottles/35395277

There are many many 20oz bottles. (Picked Walmart because if they have it, especially as a store brand, it's a commodity)