Unplug the iron's power cord from the electrical outlet.
Turn the steam control to the "Off" position.
Set the iron upright so the filling inlet sits horizontally.
Mix 1/4 cup of tap water with 1/4 cup distilled water in a spouted container. Alternatively, use undiluted bottled spring water.
Pour the distilled water mixture or spring water slowly into the water filling inlet until it reaches the maximum level as indicated by the marks on the inlet.