As you know PVA is synthesized through hydrolysis of poly (vinyl acetate). Therefore one of the important factors affecting its solubility is the amount of acetate groups that are not hydrolyzed. The more the amount of hydroxide groups  on the polymer backbone are the more the PVA solubility is. and vice versa i.e. the more the acetate groups are on the backbone the less the PVA solubility is. and of course other factors like the ones mentioned by John Hardy can play roles.

You can try 15% (w/w) in water.