Yes, it is possible to disconnect a dryer without turning the water off first, as dryers do not typically require water connections. Dryers are designed to remove moisture from clothing using heat and airflow, rather than utilizing water.
However, it's worth noting that some washer-dryer combination units exist where the dryer component is connected to the same water supply as the washing machine. In such cases, it would be advisable to turn off the water supply before disconnecting the unit to prevent any potential water leakage or damage.
In general, when disconnecting any appliance, it's important to follow proper safety procedures and consult the manufacturer's instructions or guidelines. If you're unsure about the specific requirements for your dryer or need assistance with disconnecting it, it's best to consult a professional or contact the manufacturer for guidance.