No, you do not need to turn off water supply lines when running an air conditioner overnight. Air conditioners work by removing heat and humidity from the air, and they do not require a water supply to operate.
There might be some confusion with other appliances or systems that use water, such as humidifiers or certain types of air conditioning systems that have a separate water supply for cooling purposes. However, traditional central air conditioning systems, window units, or ductless mini-split systems do not use water in their cooling process.
If your air conditioner is connected to a drain or has a condensate pump, it's essential to ensure that these components are working correctly so that the condensation produced during the cooling process is properly drained. This will prevent any potential water damage or leaks in your home.
In summary, as long as your air conditioner is functioning normally and doesn't have any water-supply-related components, there is no need to turn off water supply lines when running it overnight.