A.O. Smith offers varying warranty periods for their water heaters, which typically depend on the specific model and type of the product. Generally, their residential water heaters come with a warranty that ranges from six years to twelve years on the tank and parts. Some high-efficiency models may even have longer warranty periods. It is important for customers to review the documentation provided with their water heater for specific warranty details, as factors such as installation and maintenance practices can influence warranty coverage. Additionally, A.O. Smith emphasizes the need for regular maintenance to ensure the longevity of their products. For the most accurate and up-to-date information regarding warranties and specific models, it would be best for customers to visit the current A.O. Smith website or contact their customer support.