How To Set Up a Water Drainage System for Washing Bubble Hash

Viviane Schute        

Cannabis enthusiast and student of the art of solventless extraction


Solventless extractors use lots of water for washing bubble hash, the process of mixing together ice water and cannabis to isolate trichome heads for collection. Water is the key factor that makes it all possible. A drainage system for washing bubble hash controls the flow of runoff water that’s used in ice water extraction. 

Water plays a part in both mixing and rinsing, so lots of clean, cold water is required. After water comes into contact with the cannabis material, it’s best to let it runoff as waste as opposed to saving it for reuse. 

Water used for mixing and rinsing pics up tiny pieces of plant contamination, and also contains some plant oils and other natural phytochemicals. It’s totally safe, but it’s not ideal to use it again for extraction. 

Ideally, you can drain water directly into a floor drain, but depending on the design of your wash room, this isn’t always possible. 

Water that runs out of your washing machine or mixing vessel, plus the water used to rinse the trichomes in the wash bags, needs to be drained. You can use a basic design for drainage, directing all the water runs through the wash bags into a drainage well. A valve on the well controls the flow of water through the drainage hose outdoors or to another drain. 

A good drainage system keeps your workspace clean and safe. It prevents water from seeping into the floor of your workspace and causing damage. A drainage system allows you to wash hash in a room that isn’t outfitted with a sink or floor drain. Setting us a self-contained drainage system eliminates the need to manually carry drainage water outdoors or to an indoor drain in another room. 




Equipment List for Water Drainage System

Fortunately, you don’t need any specialty equipment to get your drainage set up inside your cold room. Everything you need is easy to find at your local hardware store, or online. 

This is the holding vessel for all your drainage water to collect. A large plastic tub, like an XL size Rubbermaid, works well. It should have an open top that’s rigid enough to support the weight of your bubble wash bag system.  


Grated Platform
This could be a grill grate (brand new, not used) or a shelf from inside a freezer or refrigerator. It needs to be big enough to extend across the width of the reservoir, since the grate will need to sit on top of the open-faced reservoir.

You can install a valve at the bottom of the reservoir, to open when it’s time to drain out the well. Ball valves work well. Note that you don't need to install a ball valve into the reservoir if you're going to use a pump. 

Drainage Hose
Flexible plastic tubing works well to drain water from the reservoir to a sink drain, indoor floor drain, or outdoors. Longer drainage hoses give you the most optionality for diverting the drainage water. 

Pump (Optional)
If your drainage well is placed on the floor, and you want to drain the water into a sink, then you can’t rely on gravity to do the job! You need a pump to move the water. Another benefit of a pump is that it already includes a valve, so you don't have to install a ball valve at the bottom of the holding well. 

How To Set Up The Drainage System

Once you have all your equipment, setting it up is straightforward. 

Install the ball valve into the edge of the reservoir, near the bottom. Use a hose clamp to attach the plastic drainage tubing to the valve. 

Place the grated platform on top of the reservoir, to act as your working surface. Your stacked bubble wash bags and bucket system will sit on top of this platform. Drill lots of drainage holes into the bottom of the outer bucket in the stack of wash bags. 

Following each agitation, water drains from the mixing vessel through the sieving bags, where loose resin is rinsed and collected. This water drains through the bucket, then through the grated platform and into the holding well. 

If you’re running water into a floor drain, place the reservoir on a slightly elevated surface, so gravity will pull the water through a drainage hose. If you’re going to pump the water, then there’s no need to elevate the reservoir. 

When the holding well gets full, open the valve and let the water drain. Be sure that the area where you’re draining the water can take on a big inflow of water. 

A pump can make drainage fast and efficient. It also has the added benefit of including valves, so you don't need to install a ball valve at the bottom of your holding well. Just run the drainage tube directly from the pump (which will be submerged under water) over the top edge of the reservoir. 

When using a pump to move the water from your holding well to another drain, be sure to use a filter sock on the outside of the submerged pump. This will reduce the tiny contaminants in the water that can gunk up your pump over time. 

Modified Trash Can Lid


A clever drainage system can be configured by modifying a 44 gallon trash can and lid. Rather than using a grate as a working platform over an open-faced holding well, you can cut a hole into the lid of a 44 gallon trash can that's the same diameter as a 5 gallon bucket. 

Then, you can place the bucket into the hole of the trash can lid, so that the bottom of the bucket is inside the trash can. The 5 gallon bucket itself is hanging inside, supported by the trash can lid. 

Stack the bubble wash bags into the bucket as usual, then drain all your water through the 5 gallon bucket. The water will run through your bags, out the bottom of the bucket, and into the 44 gallon trash can. 

Install a valve into the bottom of the trash can, to control the flow of water out of the holding well. 


Having a system in place to manage the runoff water from washing bubble hash is necessary if you want to maintain a clean, dry, safe work space. Fortunately, there are easy solutions to set up draining systems, even when you don’t have a floor drain or sink drain in your cold room. 

Depending on your set up, you can rely on gravity to drain the holding well when it fills. Or, if you need to move the water up into a sink drain, or move it longer distances (e.g. outside), then a pump is a good solution. Dropping a pump inside the reservoir allows you to move the water without any manual labor. 

How do you manage drainage water in your cold room? Let us know in the comments!

Also check out these helpful articles:

How To Build The Ultimate Bubble Hash Washing Room
How To Wash Bubble Hash
How To Make a Bucket Stacking System for Washing Bubble Hash

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What is the best way to drain water from washing bubble hash?
The best way to drain water from washing hash is straight into a floor drain. But, if that's not available, there are other ways to control the flow of runoff water. 

Do you have to drain water from washing bubble hash?
Yes, you need to drain water from washing bubble hash. As the ice water and cannabis mixture gets poured through the bubble wash bags for trichome collection, the water that drains through the bags and bucket needs somewhere to go. Leaving this water in puddles on the floor is not a good option. 

Can you reuse water from washing bubble hash?
No, it's best to dump the water after it comes into contact with cannabis, since it will pickup tiny plant contaminants and plant oils, etc. 

Where can you find a grate for a drainage system?
If you search "wire freezer shelf" online you will find a good platform to use for your drainage system. 

What type of valve can you install in your water drainage system?
A ball valve is a great choice to install in the holding well of your drainage system. 


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