Step 1 · Locate Manufacturer's Label

Walk around your water heater and visually inspect the upper half of the tank. You are looking for a large sticker, often about the size of an index card or larger, which is the manufacturer's data plate. It contains a lot of printed information, including warnings, technical specs, the model number, and the serial number. You may need a flashlight to see it clearly, especially if the water heater is in a dimly lit area like a basement or closet.