The left rear is pretty easy to get at. Remove the jack and toolkit and shine a flashlight down into the fender, you'll see the hose and drain fitting. Remove the hose and blow it backward in case there's anything in it. Chances are it's clear and the clog is actually in the drain fitting. Stick a stubby screwdriver through the fitting and snap off the diffuser nub, those are what cause the clogs. The righthand side is a much bigger PITA to get at, you need to remove the hatch sill plate and partially peel back the lower cargo area trim. Clearing it is the same exercise. When testing for rear clogs, park the car on a slight uphill. The roof orientation on the Rogues means the front drains do all the work on level ground.
The diffuser nubs are what cause all the problems at both ends, so if you haven't pulled the front cowl and busted them out, you'll do yourself a great service by doing so. Here's what you're looking for:
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