You do not. Many water bans, however, are intended to stop practices such as outside watering of lawns and plants. Typical household use is generally not included, however it should be reduced. Limit use to once per day, run as full cycles as possible, and try to use it at night. You can help reduce more by showering instead of soaking baths, and running the shower long enough to get wet, shut it off to soap up, and turn it on again to rinse. Same as with tooth brushing.
Usually the dishwasher is located near a sink. If you run the hot water at the sink, that will flush the cold water from the hot water line, so the dishwasher will end up getting more hot water during its fill, and allowing the water to reach higher temperatures. Use the "Heated Wash" option to ensure maximum temperature increase. Dishwasher detergent works best around 145 degrees, so the hotter the water going in, the better it will clean.
About 10 for a regular wash.
No, it is not recommended to use water softener salt in a dishwasher. Dishwasher salt is specifically designed for dishwashers to help soften the water and improve cleaning performance. Using water softener salt could damage the dishwasher and affect the cleaning quality of your dishes.
You ban the use of hosepipes in a drought because we want to save water an hosepipes just use up a lot of the water and if there was no water left we would die from thirst.
no or water and soap will get everywhere
To use very hot water to clean and sanitise dishes
Assuming you're running the dishwasher fully packed, then handwashing the same number of dishes would consume more water. Yet if you are running the dishwasher with not to much silverware it would save water to just hand wash them.
soap and water or use dishwasher liquid detergent with water
I recommend that you use a sink full of foamy water at a temperature of about 50oC.
About 10 gallons per regular wash.
5 gallon
About 10 gallons per regular wash.