Well it depends of the person. After one day they could be ready to pass out and never wake up again.
use sunscreen
In a developed country - of the order of 200 liters per day. If you lived in the desert, I would deduce it would be only a tenth of that.
You can use as much water as you want when you brush your teeth. The amount varies from person to person.
Three basic factors in Dehydration:How much water you drinkHow much you sweat and lose in similar use like breathing.How much you void as wasteIn the Desert there is not readily available drinking water.In the Desert the air is very dry.In the Desert the temperatures tend to be very high in day time.Rule of thumb is that People can go about 72 hours with out water, less in Desert conditions.
8 cups
About 450 liter .
About 450 liter .
50 liter water
We have more water per person than any other country in the world yet only use about 400 liters a day for residential use.
150 kilo liter
293 gal.
100-150 gallons of water