[header] How to smoke from a bong [title] Fill the bong with water. [step] Bottled or tap water will work. The exact amount of water you should pour in will vary depending on the size of the bong you're using. 
Fill up the bong so the water comes no more than 1 inch (2.54 cm) above the tip of the downstem (the long tube of glass that sticks into the bong). Any more water than that and you could get splashed while you're smoking.