No running water this morning, working on a water main on my street. OK, but...

…how come even my hot water doesn’t work?

I have, I assume a full tank. I would have expected to have hot water only, at least for a while.
mmm

The hot water tank is still full of water … but there’s no pressure behind it to push the hot water through the pipes … if it’s an electric water heater, you’ll wreak the heating elements if you run the tank dry … best to switch the breaker off until pressure is restored …

watchwolf has it - the water pressure from the street is how the hot water gets distributed from the tank to the rest of your house.

If you’re really desperate to wash your hands or something, the water in your toilet tanks (not the bowls) is clean.

Be careful of the Ty-D-bol man.

[Archie Bunker] “But that’s *terlet *water.” [/AB]

Tell that to every dog, please.

You could get some water thusly:
Find and open the circuit breaker that controls power to your water heater (planning not to close the breaker until water pressure is restored)
Locate the water heater drain valve and attach a hose to it
Drain hot water into a suitable container

This is of course rather inconvenient. And you may find that water taken from the bottom of the heater tank has a decent amount of crud in it. (Should be drained annually, but few people do this.)

And if it’s a gas water heater, turn the burner to the pilot setting. While the chance of having an empty water heater is small, if it does happen you don’t want to be putting a lot of energy into an empty heater. When water is restored, water entering a hot empty heater will flash to steam, causing a boom. Like I said, very small chance of it happening, but if you try to drain hot water from the tank it’s best to de-energize the heater.

And of course, if you haven’t used that valve in a long time, don’t be surprised if it’s frozen shut, or if once you open it, you can’t close it completely.