The piece of a water pipe that connects the bowl to the main chamber. The downstem helps provide suction, pulling smoke or vapor into the water before getting inhaled. This long piece of glass can be fixed or removable, and can have a diffuser at the chamber end, which additionally cools smoke. 

“Removable downstems make a bong easier to clean.”

“My cat knocked over my bong and broke the downstem.”

What is a downstem?

Connecting the bowl to the water chamber, the downstem provides suction to pull smoke through a bong or dab rig, causing the water to bubble in the main chamber. Smoke or vapor is then inhaled by the consumer.

Downstems can be affixed to the bong or dab rig or be removable. They come in different sizes, usually 10mm, 12mm, or 14mm in thickness. You need the proper size to create an airtight seal between the bowl or nail and the main chamber, otherwise you won’t be able to draw smoke properly. 

Benefits of a removable downstem

Most people prefer removable downstems because they can be cleaned easily. Oftentimes they are straight and can be scrubbed easily or submerged in isopropyl alcohol for a quick cleaning. With fixed downstems, it’s harder to get alcohol in there and they usually have bends, making them harder to scrub. 

Also, a glass water pipe with removable pieces is more practical—if you break a piece, such as the downstem, you can replace that piece instead of having to replace the whole pipe.