If each unit has its own individual power supply, this would suggested each one would be hooked up to the unit’s meter/switchboard.
In previous similar situations I have encountered there was a cover over the outlet which could be padlocked to stop other residents “stealing” incorrect supplies, or there was an over-riding switch in the unit itself.
I always found it was more convenient to keep my washing machine in the bathroom, they were usually big enough in those days.