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Why Do Bongs Need Water: The Art of Water Filtration

by Angel Ferrer 7 min read

why water bongs need water

Bongs need water to filter and clean the smoke, trapping impurities like tar, ash, and some toxins, making each hit cleaner than traditional dry pipes. The water absorbs heat from the smoke, and with the help of the percolator, breaks apart the hot smoke with bubbles for a smoother, cooler experience.

Bongs stand proud over all cannabis smoking devices by letting you take in a larger volume of smoke in a single inhale. This makes bongs a stronger way to smoke, but without the water, these hits would be far too harsh. In this article, we’ll explore how water works in bongs to deliver the ultimate smoking experience.


Short Answer:


First off, what is bong water?

Bong water is the liquid in the base chamber of a bong, typically added through the mouthpiece. It works with the downstem and percolator to create bubbles that filter and cool the smoke. Over time, the water collects ash, tar, and loose cannabis particles, becoming dirty and needing to be cleaned.

Pro-tip: Don’t ever leave dirty bong water to sit idle for days because it creates the perfect environment for mold to grow in your bong water. Always change your bong water after every use.


What does the water in a bong do?

what does water in a bong do


The water in a bong filters and cools the smoke, trapping impurities like tar, ash, and some toxins, making each hit smoother and less harsh on your lungs. It also helps preserve the natural flavors of your cannabis by protecting delicate terpenes and flavonoids from being destroyed by heat

To get the full benefits of your bong water, the water level must be high enough to submerge the percolator to diffuse, filter, and cool the smoke. Below we’ll go over all the different uses water has in bongs, to give an experience no other smoking device can.

The water alongside the percolator is responsible for cleaning, cooling, and diffusing hot smoke. Below we’ll discuss how the water in the bong


1. How water acts as a barrier for smoke impurities

does water filter smoke in a bong


Summary: "Bong water acts as a barrier, filtering out impurities like tar, cannabis particles, ash, and some but not all water-soluble toxins". (research by Dr. Cozzi 

When you take a hit from a bong, the water plays an important in cleaning the smoke. Water acts as a barrier, trapping impurities like tar, cannabis particles, ash, and some but not all water-soluble toxins. This filtration process means you’re inhaling fewer harmful particles, making the bong rip smoother and less harsh on your lungs and throat when inhaling.

As the smoke bubbles through the water, it catches larger debris such as ash and loose bits of cannabis, ensuring a cleaner hit. By filtering out these unwanted particles, the water helps to minimize the negative effects associated with smoking. While smoking in general is unhealthy this makes bongs a healthier option compared to many other other smoking methods like joints or dry pipes.


2. Understanding the cooling power of bong water

how water cools smoke in bongs


Summary: "Water absorbs heat from the hot smoke, which is much more gentler to inhale on your lungs - reducing the chances coughing."

The water in a bong also does a terrific job of cooling down the hot smoke, making it much easier on your lungs. As the smoke passes through the water, heat is transferred from the smoke to the water.

This happens because water has a high specific heat capacity, and when the hot smoke passes through the water chamber, the water absorbs the smoke’s heat, lowering the temperature of the smoke before it reaches your lungs.

Water bong math: If you have 100 grams of water in your bong, it can absorb 4.18 joules of heat energy from hot combusted smoke. This is why water pipes deliver much cooler smoke than any dry devices like hand pipes.

This cooling effect not only makes the inhale smoother but also reduces the risk of lung irritation which leads to coughing. Water’s high specific heat capacity means it can absorb a significant amount of heat without actually increasing the bong’s water temperature. This is why you can take back-to-back bong rips and the water will stay relatively cool, especially in larger bongs.


3. The power of tiny bubbles in water diffusion

what does water bubbles do in bongs


Summary: "The tiny water bubbles are created by the percolator, which breaks apart hot smoke, by moving it through the water chamber to be filtered and cooled."

Percolators in the bongs water chamber further enhance filtration by breaking the hot, dense stream of smoke into multiple streams as it moves through the percolator’s slits or holes. This process, called water diffusion, helps cool the smoke significantly. As the smoke splits into streams, it is further broken down by thousands of tiny bubbles created by the percolator and the draw from your inhale.

Imagine the smoke being divided into numerous streams, then further broken apart by thousands of water bubbles. Breaking the hot, dense smoke stream apart cools it down, making the hot smoke much smoother and less harsh on your lungs. Without water diffusion, bong rips would be far too harsh to handle which would lead to coughing fits. The percolator also boosts the filtration cycle by cleaning the smoke, making it the key player in both cooling and cleaning in the bong’s water chamber.


4. Enhancing Flavor with Clean Water

water and glass bongs preserves terpenes


Summary: "Terpenes which give your strain its taste and aroma, is sensitive to high heats. The water chamber helps preserve flavors by providing a cool environment. This results in a much tastier rip especially if you are using clean water."

Clean bong water is important for preserving the rich flavors of your cannabis strain. As the smoke passes through the water, it helps to protect the delicate terpenes and flavonoids that give cannabis its unique taste and aroma. Excessive heat can burn away these flavor molecules, so the water acts as a shield, preserving flavor.

Using a borosilicate glass bong with clean water is the best way to preserve the true taste of your smoke. Borosilicate glass doesn’t interact with or alter the flavor, unlike silicone or steel bongs. However, if the water in your bong is dirty, it can tint the flavor of your smoke with unwanted tastes and odors. Keeping your bong cleaner, longer will make sure each rip is rich and true to the natural flavors of your strain.


Why do Bongs Bubble?

Bongs bubble because as you inhale the smoke is pulled through the slits in the downstem, creating bubbles in the water chamber. These bubbles break apart the single stream of hot smoke, allowing it to cool and filter in the water chamber. This process helps trap impurities and delivers a smoother, less harsh rip.

The more bubbles that form in the water chamber the more the smoke is being diffused (dispersed) which delivers a cooler and cleaner smoke. To increase the bubble production in your bong you want to get a stronger percolator.

Below are a few examples of different types of percs and bubble production, but keep in mind the power of your perc depends also on the size of the bong.

  • Diffused downstem - medium bubbles
  • Inline perc - more bubbles
  • Shower perc - more bubbles
  • Honeycomb - lots of bubbles
  • UFO perc - max bubbles
  • Matrix perc - max bubbles


The Risk of Dirty Bong Water

Dirty bong water can harbor black mold, white mold, and bacteria, creating a breeding ground for microbes which is not something you want to inhale. You should change your bong water after every use because mold and bacteria can grow as quickly as 24 hours in stagnant water.

Bong hygiene is essential for a safer and tastier smoking experience. Make sure to clean your bong regularly to keep your bong’s ecosystem contaminant-free.


Can you use other liquids in bongs?

Yes, you can use other liquids in bongs besides water. Popular alternatives include fruit juices, tea, sodas, and coconut water. Each liquid can add a unique flavor to your smoking experience, but remember to clean your bong thoroughly after use to prevent residue buildup from sugary liquids like fruit juices.

Below are some popular liquid alternatives for bong water. While there is no scientific evidence to support any added benefits, these options are frequently mentioned in popular forums:

  • Fruit juices: Adds fruity flavors and enhances taste
  • Tea: Provides subtle flavors and a potential soothing effect
  • Coconut water: Adds a tropical twist and potentially hydrates
  • Cranberry juice: Prevents resin buildup and adds tartness
  • Gatorade: Adds a flavorful experience


A bong without water is a “dry pipe”

A bong without water is considered a dry pipe, similar to a weed pipe. You lose the benefits of water filtration, diffusion, and cooling, resulting in a much harsher hit. This can lead to inhaling more resin, ash, and tar per hit, making the smoking experience less enjoyable and potentially harmful.

A bong without water essentially functions as a dry pipe, much like a traditional weed pipe. Without water filtration, you miss out on the cooling and diffusing benefits resulting in a much harsher hit. This means you’re likely inhaling more resin, ash, and tar with each hit, making the smoking experience less enjoyable and potentially more harmful.

The lack of water leads to hotter, more irritating smoke that can trigger coughing and throat irritation. Below are common water pipes and dry pipes.

Water pipes:

  • Bongs
  • Bubblers
  • Dab rigs
  • Recyclers

Drip Pipes:

  • Weed pipes
  • Steamrollers
  • One hitters
  • Glass blunts


1. Do bongs filter smoke?

Yes, bongs filter smoke. The water in the bong traps tar, ash, and some water-soluble toxins, resulting in a smoother and cleaner hit. This filtration reduces harmful substances in the smoke, making it less harsh on your lungs compared to other smoking methods.


2. Do all bongs use water?

Yes, all traditional bongs use water to filter and cool the smoke. The water traps impurities like tar and ash, providing a smoother, cleaner hit. Without water, a bong becomes a dry pipe, losing the benefits of filtration and cooling, leading to a harsher smoking experience.


3. How does water filter smoke?

Water filters smoke by trapping larger particles like tar and ash as the smoke bubbles through it. This process removes impurities, resulting in a smoother and cleaner hit. The water also cools the smoke, making it less harsh on your throat and lungs.)