The water in a bong cools smoke, filters ash and tar, and improves airflow, without removing THC. It transforms hot, raw combustion into a smoother, cleaner inhale. Proper water level and temperature make each hit less harsh, more enjoyable, and better for your lungs.
Bubbles Aren’t Just for Show, They Serve a Function
Water in a bong cools smoke, filters ash, and controls the way air flows through the piece.
The bubbling isn't decorative. It shows that combustion is being broken down and restructured before it hits your lungs. That visual cue means the smoke is passing through water, picking up less junk and losing some heat.
Without water, you're pulling raw heat, resin, and particles straight into your chest.
That kind of hit might work once, but you're not going to enjoy it twice. With water, each inhale feels smoother, more controlled, and cleaner.
If you're new to glass, skip anything complicated.
A straight-shooting 12-inch beaker with a slit diffused downstem will outperform most setups. It's easy to fill, hard to knock over, and made to handle heavy use.
This Thick Ass Glass model is built from 9mm glass, comes with proper accessories, and has the kind of draw that actually lets you feel how well it's working.
Start with good basics and you'll avoid most of the frustrations people run into with bad glass. A beaker is stable, easy to clean, and delivers what it promises every time. Now that you’ve got a solid piece, it’s time to see what the water’s actually doing in there.
What’s Really Going On Inside the Chamber
People love to overcomplicate how bongs work. Some talk about vortex physics, others go full pseudoscience with claims that water changes the structure of smoke.
In reality, it’s simple. A good bong takes hot combustion, pushes it through water, and sends you filtered smoke that’s easier to inhale and easier on your lungs.
Combustion Basics
When you light your flower, combustion kicks off instantly. Heat transforms plant matter into smoke, and it begins moving down the bowl and into the downstem.
This smoke is packed with heat, tar, ash, and all sorts of particles that would otherwise end up in your throat. At this point, nothing has been filtered. It’s just raw output from the burn, and it’s moving fast.
Bubble Formation
Once the smoke hits water, it doesn’t just pass through. The water forces the smoke into small bubbles.
These bubbles increase surface contact between the smoke and the liquid. That’s where filtration begins. Ash, heavier debris, and some water-soluble compounds get left behind.
The bubble structure also drops the smoke temperature fast. The more diffusion you have, the more effective this cooling becomes. Percs, slits, and diffusers all play a role in maximizing bubble geometry.
Upward Draw
When you inhale, you create a vacuum that pulls the now-filtered smoke up through the chamber.
It travels through cleaner air space, cooler than when it started. THC remains in the smoke because it is not water soluble. It doesn't get trapped or absorbed. It rides the airflow and reaches your lungs with its potency intact.
That visual cloud you see stacking in the chamber? That’s filtered combustion, minus the garbage.
So when people ask why the smoke doesn’t dissolve into the water, the answer is chemical.
THC stays airborne. Water just helps it arrive in a smoother, cleaner form.
What the Water Catches and What It Lets Go
A lot of people think water somehow "steals" THC or changes the strength of a hit.
That’s not how any of this works. What water actually does is act like a first-pass filter. It removes the junk while keeping the stuff that matters.
You still get high. You just get there without coughing up a lung or tasting burnt resin on your tongue.
Filtration in a bong is about separation.
Smoke carries everything up from the burn, good, bad, and toxic. Water can’t remove everything, especially gases or non-polar compounds, but it grabs what it can.
That includes the visible stuff you’d rather not inhale.
Filtered Out
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Ash
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Plant debris
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Some polar toxins like tars and water-soluble irritants
Passed Through
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THC
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Terpenes (unless the water is already dirty or you overheat the flower)
Extra Benefit
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Water adds controlled drag to the pull
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That resistance softens the draw and gives the hit a quieter, cleaner feel
The bottom line is that the water in a bong does a specific job. It cools, it filters, and it manages airflow. It doesn’t remove potency. What it does is remove trash.
And if you're using clean water and quality glass, that trash never makes it to your lungs.
Fill the Bong Exactly to Right Level
Most complaints about a bong come down to the water level. Too high and you’re sucking water into your mouth. Too low and the smoke hits harsh and dry.
You want the water to interact with the smoke, not fight against the design of the piece.
Each style of bong has its own range where performance is at its best. That means learning to read your glass and adjust the fill with care.
Straight Tubes
Straight tubes are efficient. They clear fast and hit hard with minimal drag.
That only works if the water level is right. You want just enough to submerge the bottom of the downstem. If the slits or holes are exposed, you're not getting the cooling or filtration the design is meant to deliver.
Too much water slows down the hit and pulls moisture into the neck. A well-balanced straight tube should feel crisp and fast without splashing.
Our 14-inch straight tube with nails that balance and gives you some space to work with.
Beakers
Beakers give you more room and more water, which translates to smoother smoke.
Their wider base helps with stability but also allows for more cooling before the smoke hits your throat. You still don’t want to overfill. Just cover the end of the downstem where the diffusion happens. That gives you clean percolation without making the draw feel heavy.
If you use a large beaker like our 16-inch Bamboo Beaker Bong, you can fill it with a larger volume of water to get proper resistance without choking the airflow.
Perc Rigs
Percolator rigs are all about controlled diffusion.
These chambers need the right amount of water in each section. If you underfill, the perc doesn’t activate. If you overfill, you end up with restricted flow and splashback.
Each chamber has a purpose, and each one needs water.
The 12-inch Fab Egg Klein Incycler is a good example of how Thick Ass Glass utilizes function-first engineering. It gives clear feedback when filled correctly and stacks bubbles like it was designed to do the job, not just look like it could.
Cold Water. Warm Water. Ice Cubes. What Should It Be?
Most people fill their bong with cold tap water and call it a day.
That works, but temperature tweaks can shift the entire feel of a session. Water doesn’t just affect taste. It changes how smoke flows, how your lungs respond, and how long you can hold a hit without discomfort.
Temperature Makes a Difference
Cold water is the default for a reason. It pulls heat from the smoke quickly and makes each inhale smoother. You feel less bite in the throat, and the hit goes down easier.
Add ice to an ice catcher and you push that even further. Ice doesn’t just chill the smoke. It adds mass that forces the cloud to snake through a narrower space, slowing it down and cooling it more efficiently.
Warm water changes the game. Some smokers prefer it in colder months or when they have sensitive lungs. It won’t filter as well as cold water, but it softens the feel of each pull and opens up airflow slightly.
Hot water rarely comes up for good reason.
It removes the cooling benefit and can increase throat irritation. And no, cold water doesn’t remove THC. That’s a myth. It just makes the whole experience smoother and more controlled.
Dirty Water Means Dirty Smoke
Bong water doesn't age like wine. After a session, it's full of ash, tar, and whatever your lungs were lucky enough to miss. Let it sit, and it turns into a stagnant pool of bacteria and bad taste.
Smoke moving through that doesn’t just pick up old residue. It carries the smell and the flavor of whatever has been festering in the chamber.
You should be changing the water after every use. Not every day. Every session. If the water looks cloudy or smells like a sink trap, it's already too far gone. Clean smoke starts with clean water.
Once a week, rinse the bong with hot water. Let it flush out the buildup in the downstem and chamber before it turns solid. You paid for glass that functions. Give it what it needs.
Nobody is impressed by stale resin clouds floating above swamp water. Keep it clean or stop pretending it’s filtration.
Can You Use Liquids Other than Water in a Bong?
The short answer is yes, you can use other liquids. The better answer is you probably shouldn’t.
People try all kinds of things to boost flavor or novelty, but most of them make your bong harder to clean and worse to use. Liquids with sugar, acid, or alcohol introduce new problems that have nothing to do with performance and everything to do with maintenance, safety, and hygiene.
Here’s what to avoid and what might be worth trying:
Don’t Even Thing About
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Juice
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Soda
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Alcohol
These all cause either mold, sticky residue, or toxic vapor. Your lungs were not built for fermented apple sugar or burnt cola syrup.
Helpful Resource -> 10 Bong Water Alternatives
Optional Tweaks
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Chilled distilled water
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Fresh mint leaves
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Glycerin coils if they are outside the water chamber
Flavored water doesn’t do much except get in the way of the flower.
Terpenes carry most of the scent and taste. Drowning them in artificial lemon doesn’t make the session better. It just masks what you paid for. Stick with clean, simple setups unless you’re testing something for fun and ready to scrub the entire rig afterward.
Water Is A Bong Smoker’s Best Friend
The role of water in a bong is to transform harsh smoke into a clean, smooth experience.
It filters debris, cools heat, and helps you control every inhale. Once you dial in the right fill, temperature, and maintenance, the session feels less like guesswork and more like precision.
If you want smoother and more enjoyable smoke, start with better glass. Thick Ass Glass builds bongs with stable bases, engineered downstems, and real durability.
Browse the full bong collection at Thick Ass Glass site and find the piece that turns won’t be too hard to fill with fresh water before every session.