I think he NEEDS to have a shop look at this to be sure what is going on, since he definitely doesn't seem to have much mechanical knowledge. While the "sky is probably not falling", it could be something really serious........and continued driving might be a disaster.
Which is the gasoline water pump? Can you send me a pic or a link??? Posted via the PriusChat mobile app.
Take a look at the first post in this thread: Belt change how-to with photos Although it about changing the serpentine belt, it shows quite clearly where the ICE coolant pump is located. The photos are taken from beside the right fender looking towards and down to the engine block. hope this helps.