How do I know if the paint I bought is water-based? October 19, 2023 17:40 Updated All ECOS paints, stains, varnishes and specialty products are water-based. Related articles How do l know if I need a primer? Does your paint contain any rust or mildew inhibitors? How do I know what ingredients are in your products? What is the difference between the ECOS and Lullaby product lines? How long does ECOS paint last once opened?