I was interested in the "shelter in place" scenario, especially of the kind where I can't actually leave the house (eg because of quarantine).

It might be, if it had references. As it is it makes bold, scientific-sounding statements with nothing to back them up. For example, "300ml of water is sent to the urinary and digestive tract for each 1L consumed. 500ml is sent to the urinary and digestive tract when you consume caffeinated beverages, such as coffee." This contradicts what is written on other sites, eg from http://www.pponline.co.uk/encyc/caffeine-dehydration.htm:

• A similar study considered the effects on hydration of different levels of caffeine consumption (5). Eighteen healthy men consumed each of four different drinks: pure water, water plus cola, water plus diet cola and water plus coffee. Body weight, urine output and blood samples were measured before and after each treatment, and there were no significant differences in the effect of the various combinations of beverages on hydration status.

I'm afraid the Boreal article, as written (were you the author?) doesn't carry as much credibility because it doesn't describe original experiments or cite references to such. And of course, my own experience wins. I have measured what I drink on other occasions, living my mundane working life, and it usually comes to about 1 litre per day.