Water repellents offer the advantage of preventing water from penetrating concrete surfaces without significantly changing the appearance of the concrete. However, because various types of concrete surfaces have different absorption properties, there is no one water repellent suitable for all applications. To further complicate the selection process, most commercial water repellents have traditionally been solvent-based. Today, restrictions on the permissible levels of volatile organic compounds (VOCs) are forcing manufacturers to change the chemical formulations of water repellents to comply with current and future regulations. Selecting the product that offers the best water-repellent properties and VOC compliance for the type of concrete surface on which it will be used is not always easy. Using a worksheet can help make the selection process easier and more accurate.