New Big Country 3450 TS Owners Need Help Figuring out Grey Tanks

First time out with new Rig and are just getting acquainted with everything on it. What do they Grey 1 tank and Grey 2 tank hold and where does the source come from--kitchen sink, shower, etc.? These seem to be different than on our previous unit. Don't mean to sound dumb, but can anyone help us?

I think #1 is the kitchen and #2 the bath, I, sure if that's wrong someone will chime in.

On our unit the No1 tank is the front tank and is for the washing machine and the bathroom. The No2 tank is for the sink in the kitchen only. The bathroom tank is just below the black tank just ahead of the front storage frame dropof. The kitchen tank is over the wheels behind the Fresh water tank. I was looking at these tanks just the other day on my unit as the signiture shows. On my unit being a Canadian model the tags on the tanks are in Imperial gallons showing 45,45,45,75 ImpG each. Now not sure about american units if they are USG capacities.

I agree that the grey 1 is bath and washer, and grey 2 is kitchen.

Thanks Alan
After I wrote the last response I started to wonder, its been 3 months I have not pulled the gray tank drains. I feel it goes front to back in numbering the tanks.

I couldn't ever remember so I made a label and stuck it on the monitor panel.