Probably due to a shortage.
Probably best to restrict your water use until you have found out why it is flooded.
You might use a toothbrush. You might use soap. You might use a sponge. You might use a towel. You might use a facecloth. You might use a facewash. You might use water.
No salt water could get you sick!!
to clean or give water to the animals
In the Later Roman Empire enemies who besieged Roman cities damaged the aqueducts which took water the the cities to disrupt or cut off the water supply.
Polo
They don't need water
It was made illegal in 1970. The federal government does restrict its use in a religious ceremony but state governments can restrict it.
If its dry in an area, that means the water is scarce, therefore they need to conserve water in order to survive. They might get water from cactuses, low in the ground, or other plants. They might then drink just enough water to survive and still conserve the water. In cities with low rainfall there may be restrictions on water use, for example, the use of sprinklers in gardens may be forbidden, or the use of hoses to wash cars.
That's difficult to say, because the amount of soap required depends on the hardness of the water. The rule of thumb is well water has more dissolved minerals - is "harder" - than city water...but many cities use wells or aquifers to supply their water, and as a result the tap water in those cities is very hard.
Unless your religion or a health defect restrict it, no.
What conveyed water to the cities was the aqueduct. What made the construction of long aqueducts which needed bridgework was the arch. The Romans were not the first to use the arch, but they were the first to make widespread use of it. Prior to the Romans, the arch was rare. The structural strength of the arch made the construction of large buildings and bridgework possible.