Do you need to sand between coats of water based gloss?

Great question! As it is not a requirement to sand between coats when painting, to ensure the best possible finish and leave your customer happy, I would most definitely recommend it. A light sand using 220 sand paper will give you good adhesion on your top coat of gloss as well as knock down any dust or debris that has made its way into your finish. Remember only a light sanding is needed, so don't go making a mess, and always make sure you use a damp cloth to wipe up all of the sanding dust. Good luck, and Happy Painting.