Most likely water sitting in the housing of your second stage. If you shake out the second stage and then hang the reg so the second stage is the lowest part, this will usually be enough to take care of that "spray".
Fresh water can have particulates in it that can damage your gear. Soaking a reg in heavy tap water (with lots of ions, chlorine, etc) and not shaking it out or purging it, can lead to salt build ups as well.
On that note, might want to inflate your BC up then give the corrugated hose a shake and tap then see what comes out. There's always moisture there unless you have some light heat and very low humidity. I often shake as much water out, let it hang fully inflated, then shake some more out every half hour until there's no drops. Then I hang it up in my bedroom closet.
Even if you're diving a fresh water quarry, it's nice to give your BC a good tap water rinse to rid the gear of silt and debris. If you water is really chlorinated or heavy then perhaps sacrificing a quick finishing rinse from your PUR or Brita filter might not be a bad idea.