I think most new Forest River products have inline water filters.
Per your other 2 threads trying to locate your water filter.....it should be near the outlet side of your water pump. For a 2007 model, I am not sure they put water filters on many models that year.....it was listed as a "Standard Option", whatever that means.
Here is the 2007 Flagstaff brochure: http://www.forestriverinc.com/nd/ult...7flagstaff.pdf
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263