Salt
It will certainly not keep the water in the bucket from freezing and, if the temperature goes low enough, the bottled salt water will also freeze.
Light a fire next to it.
Salt lowers the freezing temperature of water, which means that it has to be colder for the water to freeze.
Adding vinegar to your dog's water will not prevent it from freezing. To prevent dog water from freezing, consider using a heated water bowl or changing the water frequently to ensure it does not have a chance to freeze.
It changes the freezing and boiling point.
Believe it or not, you can keep water protected in Antarctica by keeping it in a fridge. The temperature is so cold that a fridge could keep it safe from freezing.
Coolant container will say if it is pre-mixed or full strength. If full strenght, mix it 50/50 with water. Pre-mixed coolant can be added "as-is"
It is possible to keep water as liquid below its freezing point - see related link.
thaw it under the sink with hot water. then keep it in a bucket of hot water
Because alcohol has a lower freezing point than water. By mixing it with water, you lower the waters freezing point. So it keeps the water from freezing on the windshield.
In a location where the temperature does not fall below the freezing point (32 degrees Fahrenheit)
Keep in the refrigerator or if u want it REALLY cold try freezing it