Yes, it is possible to spray paint with a water-based product with a cordless paint sprayer. However, you have to make sure that it is a water-based product that you are using. You have to look at the product container or research the product to see if it is water-based or not. If you are not sure, it is always better to use a water-based product than a solvent-based product. If you are using a water-based product, the water-based product should be mixed with water and you should use plenty of water to make sure that there is always water mixed with the water-based product that you are spraying.