Vinyl liner pools are one of the most popular construction methods in Canada for many reasons—one being ease of maintenance. For example, it is harder for algae to grow on vinyl than on plaster. However, even the highest quality vinyl liner is still subject to staining and discolouration. Improper water balance, water treatments, and specific types of debris can cause persistent maintenance problems, most notably staining on vinyl surfaces. This article provides a brief overview of how typical staining occurs to help service professionals take care of these persistent maintenance challenges.