Yes, you do.
Just like your espresso machine needs a water filter under the counter to filter the water first, Perfect Moose Jack also needs filtered water to provide top quality microfoam and protect your device.
When you haven't used your installation or a while, it is recommended to rinse the water filter first. Check your water filter model and rinse according to the instructions of the manufacturer. Just like you would with your espressomachine.
Do I need a water filter to install Perfect Moose Greg?
When you are planning not to use Perfect Moose Jack for longer than 1 week, drain all the water from the boiler. When restarting your machine, just follow the start-up procedure. One of the steps is refilling the boiler with fresh water.