Hot WATER goes on the WATER bill, and making it probably goes on the electric bill.
Not pure water - salt water can - hot or cold.
No, cold water is piped into the hot water tank and is heated by electricity or gas, it then flows out to the hot water taps.
Because the water is hot!
thermopile
It is the process where sunlight is converted to electricity (not hot water).
Most houses still use electricity for energy but it is better to get hot water/solar panels to get rid of your electricity bill. Though you'll need more than one to completely dissolve it.
not if your heating with gas and not if you have city water
hot water
The hot water warms the refrigerator, which forces it to turn on to cool it off.
Not significantly. Using less hot water in general will save.
Yes, your gas water heater will still distribute hot water.
Tap Water is flammable, because it contains Methane gas. However, pure water itself (unaffected by other chemicals) is not flammable. The previous answer about dripping water onto a heated iron is incorrect. If the iron is hot enough, the water will just evaporate, producing no flame.