Fuel/Water Separator, National Tropical T33 w/Cummins 300

In another vehicle it was directly below the fuel filter

Bump. This info is for my neighbors who are heading out in their motor home tomorrow. If you don't know where the fuel/water separator is, do you know where we might inquire on the net or otherwise?

Thank you for reading and any help will be greatly appreciated. I could always call my neighbors with the info while they are on the road.

Dawn & Kevin