Just added washer fluid to the front reservoir that is under the hood. Is that reservoir for the rear washer too??

The book only mentions the one under the hood so I have a feeling that feeds the rear washer too.

Put in the new RainX washer fluid as my son has been using it & the rain seems to kind of just blow off the windshield.

 

Yes, there's a single reservoir under the hood that serves both the front and rear windshields.