Gurgle Gurgle...
...go the empty water pipes. You'd be surprised how noisy empty water pipes can be.
My school had no water for 24hours (almost exactly), from Wednesday evening until Thursday evening when it started to snow. It's a good thing the water came back too, since the buildings are heated by hot water radiators. The high temperature of the day was a balmy 4C, and as soon as the sun went down it started to snow. Imagine no heating.
Of course, no water also means no toilet flushing and no hand washing. Please don't imagine the smell. Luckily I noticed the drop in water pressure on Wednesday night so I got a kettle and a bucket full of water for tea and hand washing.
Nobody knew why there was no water, nor how long it would take to be restored. It was quite odd though that the sprinklers at the front of the building were able to water the clover for 5hours.