Curious. I have a month of water, three days of food and a day of beer.
And I suspect we have nearly an identical inventory.
What Alley Dweller said, I think.
First, fear that the water supply might be contaminated.
Second, fear that the people who keep the municipal utilities running might be out, and the water supply might be unreliable.
Now, what about our other utilities? My apartment is all-electric. I cook in the microwave mostly, but the stove is electric too. Much of the food I have around requires some cooking, for which I need water and electricity.
I’ve got about a five-day water supply.
How do I stock up on electricity?
Hell, just drink your urine.
The strangest thing people have been panic-buying in the grocery store I work at is foil seasoning packets - you know, the pre-mixed, pre-portioned spice blends for things like taco meat, or sausage gravy, or spaghetti sauce.
I guess you can’t let a little thing like the collapse of civilization stand between you and Taco Tuesday.
The tap water in my house tastes like shit. I can’t even make coffee with it. So, bottled water.
And if you run out of bottled water during a lockdown, are you just going to die of thirst rather than drink your tap water???
I was thinking about the OP’s question the other day at the grocery store. A dude was asking a clerk where things like milk, water, etc. were in the store. Clearly did not shop much, if at all. But was panic buying.
Milk isn’t going to last long compared to a decent length period of holing up from everyone.
And like the OP, it would take a pretty bad situation before most people’s tap water stopped flowing.
Taste? Who cares what it tastes like. If you get thirsty you’ll drink it. Compare yourself to Bear Grylls drinking “water” squeezed out of elephant dung and consider yourself lucky.
We need to distribute the (electronic version) of The Hitchhiker’s Guide to the Galaxy just so everyone will see those comforting words on the cover: Don’t Panic.
I have a Brita pitcher. I mostly use it for filling and refilling my cat’s water dish as she hates the tap water. Which, fair enough; I dislike the taste, too.
Not only this, but water is moved by pumps. And therefore susceptible to interruptions of either power or the water utility itself. Those big water towers you see dotted around the city have less than a day’s supply stored.
Another concern involves the chemicals used to sanitize and prepare the water prior to its movement toward the customers. Who supplies those products? I’d bet at least some of it comes via containerized freight, which would make it at risk now.
I actually asked this same question in the other Corona thread and Broomstick answered it pretty well (like here).
Utilities do not invest in backup capability, preferring to spend as little as possible on maintenance (PG&E anyone?). So I’ve long considered it prudent to prepare for temporary household independence from the “the grid”, be it power, water, food, or fuel. As such, we’ve done absolutely nothing due to the Corona virus. We did all that long ago and are just waiting (and hoping it was wasted effort).
We don’t bother stocking water except in the RV for in-rig use. Our forest abode sits below the water district’s local tank which is fed by pipes running from mountain lakes. Gravity all the way, and there’s still a snowpack, so no worry. Water tastes better since they laid pipes to replace the open aqueduct. Water had tasted funny when bears fell in the trough and decomposed, sending flavor bombs downstream. Kool-Ade helped.
If things go bad… We almost ran out of gas in Mexican mountains far from the nearest Pemex station. Luckily, a campesino’s gasolina stand sat beside the road. He sold us a few liters in milk jugs for only quadruple the Pemex price. Lesson learned: Stock up on water so you can gouge the desperate. Be armed, just in case.
I think it’s excessive worry. There was a thread someone on Straight Dope about how coronavirus could destroy civilization. It won’t, but if that somehow happened then the water treatment plants would stop working.
If I were worried, I would stock up on juice because I hate flavorless water.
I know people from all over the country who knows/thinks their tap water is bad.
It’s been a meme for a long time that in the post-apocalyse world the two things that will be universally barter-able are .22 short rounds (for hunting) and spice packets (to make all your survival food more palatable) since the meme is that 1000 years ago people were literally willing to die in exotic locations just for some spices to take home.
When I lived in apartments in hurricane territory, we had candles and matches, multiple flashlights and batteries, a hand-crank radio/flashlight, a solar battery charger, and canned food we could eat cold. Be sure to have a manual can opener as well.
You can refill a water bottle from the large, cheaper-per-unit, and apparently still in-stock jug.
(And why is it easier to smuggle a bottle of water than a jug into a football game only if you’re a guy? I mean, I know why it’s easier to piss into a bottle if you’re a guy. But why would it be easier to smuggle a bottle if you’re a guy?)
Personally, I’d use the hand pump. 
It also, unlike the main well, doesn’t require electricity.
Failing that, I’d dunk a bucket into the pond, or in a pinch the lake (which is further), and boil the contents before drinking.
(Yes, I know. Many people who have their own well don’t also have a hand pump; and some of them don’t have access to a pond or lake or creek.)
More or less what susan said:
You can now get battery-powered LED lamps in addition to the flashlights. If you have small children, or cats, or think you’ll react by getting into the wine enough to screw up your reflexes, I’d avoid the candles technique. You can also get battery packs to recharge your phone and/or tablet.
As far as hot food, you can get a camping stove; or, more cheaply, a Sterno set up. Of course, if you’re in ah area that’s had panic buying, those might be sold out. Consider it the next time they’re in stock, if so. We’ll probably live through this one. – they seem to be in stock online, though, at least judging by the first Google hit I got, which is the one in the link. All sorts of places carry them.
Usually I see this done with generators and fuel to power them. At least, that’s how it was done when we were afraid of an icestorm causing massive power outrages again.
You might also pack some batteries and the occasional phone wire converter to DC electricity. Also maybe some solar powered stuff, and flashlights that you shake or spin.
Yeah, well, here on the south shore of Lake Michigan you don’t want to drink out of the big lake due to all the steel mills lining the shore… Ew. Just ew.
I suppose we could dip into the local drainage canals but with all the heavy industry in the area… um… wow, that’s more risky than you might think.
I’d be better off fitting a hand pump to the well at my old residence - yes, it’s local water but it had been tested yearly for decades and was still wholesome at last check.
Although if things got that bad for any length of time I’m heading out for other locations. But I don’t think we’ll be having that particular emergency this time around.
MRE with flameless reheating packs. Food is mostly OK, FRH work OK and can use polluted water as you are reheating food in retort pouches. Some MREs also come with little esbit stoves, set them on a windowsill on a brick, bob’s your uncle.
Sounds good. Sadly for us, my spouse has a medically restrictive diet that precludes almost all ready-made food, but fortunately she likes garbanzos. Hummus all around in our apocalypse.
I have infinite water (if you count the lake, which I happily will drink from anytime!), food for me and my two cats for about a month, and wine for six months (a 30 gallon barrel; the other one is mostly finished by now, and won’t be replenished until late summer!) 
I’m operating on the theory that beer is ≈95% water.