Recent studies have shown that U.S. water mains are failing at an accelerating rate. In the meantime, water utilities are challenged by limited funding. It is important that water mains with much higher likelihood of failure (LOF) are replaced before they fail to avoid possible high consequences, such as public safety threats, high financial losses, and environmental damages. This article presents a model to evaluate the LOF of water mains using data available in geographic information systems (GIS). A case study is presented comparing 2 years of actual water main break data with the results of the model. The comparison shows a strong correlation between the model prediction and the actual break rates of main pipes; thus, it validates the robustness of the model and shows that funding can be used more efficiently by focusing on the water mains with a high LOF as predicted by the GIS model. This model has been used in New Jersey American Water's distribution systems. It can be used in other water systems to help guide water main replacement efforts.