Probably low coolant.
If there is a significant amount of water in the fuel tank, then there will be a warning light.
Probably means you running out of fuel and need to get a refill.
it should not be a water in oil tank it is mean engine cracked
If you mean no water in the radiator, the answer is NO.
It is warning you that you are low on fuel and need to stop and fill the tank.
If you mean a well tank, the water is forced in by the pump. The residual air pressure pushes the water out to the faucets.
What do you mean by "weird"?
It is a reservoir or tank for holding water
A warning light on the dash board of a Chrysler Sebring that has an exclamation point has to do with the tire pressure monitor system. Another warning that is a solid light is referring to air leaking into the gas tank.
What do you mean by hot water system? If you mean hot water tank than a three wire hot water tank means that its 220 volt electric. If you have to ask than don't touch it
If you mean the toilet tank, it means you have a leak and water (and $$$ if you have a water meter) are being lost. It is the same as a leaky faucet. You need to find the source of the leak and repair.
No. Just the main tank. The warning light comes on with about a gallon left in the tank, in my experience.