A good paint for shower walls is an epoxy paint. A primer should be used to improve the durability and adhesion of the epoxy paint.
Paint designed for use on shower walls is designed to handle high moisture levels. Bathroom paints dry into a film that is easy to clean, resistant to water, and biocidic, which makes it resistant to mildew and mold. Using a primer, epoxy paint and a sprayer can provide a smooth finish that may make a shower look like new. It is important to sand the shower to remove any scratches and then clean it with muriatic acid until the shower is smooth before beginning to paint.