I have a 2007 Suburban that everytime we fill the windshield wiper fluid it leaks out the back of the suburban. I can't find the water line in the rear to replace it. I cannot get in water to stay for the back windshield wiper!!

Windshield washer line is a very small diameter black hose. Easiest way to find is at the rear driver side corner look directly UP. It has a small plastic fitting to hold two splices of line together and they commonly come apart (I have a 2007 suburban and mine does too).
I'll try to upload a photo showing the line on mine. I wrote some areas of reference to try to help pinpoint what you're seeing.
Make sure that piece is connected (if you're losing the fluid under the rear driver side I'm fairly certain the connector came apart).
https://cimg2.ibsrv.net/gimg/chevrol...06cf802a55.jpg
Picture underneath rear driver side bumper showing window washer fluid line

Edit: make sure you dont pull the line and disconnect from somewhere else... mine was disconnected behind fuse relay under hood AND under rear bumper area when I got it.

Cargo area leak
 

Have a rear cargo leak in my Tahoe as well but don't know where it's coming from the headliner towards the back doors are soaked and water has leaked clean through the left rear speaker in the cargo area however the carpet is mainly soaked on the left side and all the way across at the rear doors in the cargo area but after a few days of rain most of the cargoes carpet area are wet I've only had the truck a few months bought it as is from a title loan it has a roof rack and looks like it have an after market roof brake light