It will vary from model to model. On my Compass 23TR, there's the fresh water drain and two low level water drains - one for hot and one for cold. To get to mine, I had to pull out the drawer under the microwave and they were right there.
If you don't mind crawling around under your rig, look for two uncapped pipes pointing straight down. Those would be the low water drains. Take note of where they are. Then go inside and see if you can get to them.
__________________
|