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BOROUX foundation.™ Black Filters

product $140

BOROUX foundation black filters are compatible with popular water filtration systems. They ensure years of reliable service with a lifespan of up to 6,000 gallons per filter (12,000 gallons per pair). The filters, equipped with Stem Saver technology, are reinforced for added durability during handling and cleaning.

HSA/FSA Eligible at Checkout.

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Key Features

The BOROUX foundation.™ filter is meticulously designed to seamlessly integrate with most gravity-fed water filtration systems including Berkey®, ProOne®, Alexapure Pro, Doulton, Patriot Pure Ultimate, and more. Whether it's refreshing your existing setup or initiating a new journey in water wellness, the filters have been crafted for broad compatibility with gravity-fed systems.

Full compatibility details here

Product information

We offer free shipping on all orders over $60 to the U.S. and Canada.

Boroux encourages customers to test products once they are received. For this reason, we accept returns of products in new or used condition. If you are not satisfied with the purchase for any reason, within 60 days of receiving the package, please get in touch with Customer Service.


The lowercase styling of 'foundation.' in our name speaks to the inherent simplicity of BOROUX. By choosing 'foundation', we reflect the straightforward and essential nature of our water filtration solutions—designed to be uncomplicated and accessible.


The period at the end of "foundation." symbolizes finality and completeness. It's a subtle way of saying that BOROUX foundation. is the definitive answer to water filtration needs. It's a complete solution, and there's nothing more to add – it's the final word in water filtration.


Just as the name "foundation." is grounded (with the period acting as an anchor), BOROUX is grounded in nature and its commitment to the environment. The name resonates with the brand's dedication to being a reliable foundation for filtered water solutions.

Rigorous Performance, Verified Data

Each filter created is a testament to a firm commitment to transparency. Undergoing meticulous testing procedures, the filters come with verified performance data that guarantee you receive water filtration you can count on. This product was designed exclusively to enhance municipal tap water. With each drop filtered, rest assured, you're enjoying the pinnacle of water filtration.

Reinforced Stem Saver™ Design

Recognizing the challenges of filter handling and maintenance, the BOROUX foundation.™ have been re-engineered with the innovative Stem Saver™. This advancement fortifies the most vulnerable part of the filter—its stem—against breakage, ensuring it can endure the rigors of regular cleaning and handling.

Uncompromising Quality, Direct to You

The BOROUX foundation.™ stands out by offering premium filtration directly to your doorstep. Eliminating middlemen ensures that each filter is a blend of top-notch quality and value. This direct-to-consumer approach provides superior hydration without the premium cost.

Designed for Universal Fit

Our filter is meticulously designed to seamlessly integrate with most gravity-fed water filtration systems. Whether it's refreshing your existing setup or initiating a new journey in water wellness, the filters have been crafted for adaptability.


Filter Capacity  Up to 12,000 gallons per pair depending on the quality of the influent water.*
View test results here.
Dimensions 2.75” x 2.75” x 9.75”
Composition Filters are comprised of a specialized blend of activated carbon. The BOROUX foundation filters contain silver, an antimicrobial agent, to prevent microorganisms from degrading the product itself. This filter is not intended to filter microorganisms.

Fits most gravity-fed water filtration systems and fluoride filters.

Warranty Coverage  BOROUX foundation filters are protected by a 1-year quality warranty. For further details on our warranty provisions, please contact customer support.
Maintenance  Scrub the BOROUX foundation filters every 3-6 months. Using an abrasive scouring pad, carefully scrub the surface of the filters for several minutes. DO NOT use soap or detergents on the filters. Re-prime the filters, install, and perform the red dye test to ensure proper installation of the filters. 
Replacement Filter  BOROUX foundation filter / Model BX·FND9·2
Box Includes
  • Two BOROUX foundation filters
  • Blue Priming Tool
  • Red Dye Test Solution
  • Tan Priming Tool
  • Product Insert

*Based on independent testing for the reduction of chlorine at 6,000 gallons per filter. While testing was performed under standard laboratory conditions, actual performance may vary. The contaminants or other substances removed or reduced by these filters are not necessarily in all users' water. Filter performance may vary based on local water conditions.

Compatible Water Systems

The BOROUX foundation.™ is designed with versatility in mind, fitting seamlessly with a range of systems. Below is a list of popular systems the filters fit in.

System Model
Berkey® Travel Berkey®
Big Berkey®
Berkey Light®
Royal Berkey®
Imperial Berkey®
Crown Berkey
AlexaPure® AlexaPure Pro®
Aquacera® Terra2
Doulton® PioneerTM SS4
Patriot Pure Patriot Pure Ultimate
ProOne® Big+
Big II
Waterdrop®  Waterdrop® King Tank

Don’t see your system listed? We’re here to help determine compatibility. Your feedback helps us expand our list of compatible systems. If you don't see your filtration system model, please send us an email at with the make, model, filter housing dimensions, and any other important specifications.

Frequently Asked Questions

How long do the filters last?

The filter lifespan will vary depending on the source water and contamination level. The recommendation for when to replace depends on several factors. For example, for filtering chlorine, the filters last for 12,000 gallons per pair. See recommendations for other contaminants.

How do the filters work?

BOROUX foundation filters work by absorbing and trapping contaminant molecules. The carbon attracts and absorbs molecules with a certain chemical charge. They stick to the carbon, like how a magnet attracts metal. The tiny pores of the carbon block are so small that they physically block and trap tiny particles. It's similar to a sieve or strainer.

What is the BOROUX filter made of?

A specialized blend of activated carbon.

More FAQS here

Customer Reviews

Based on 264 reviews
C.S. (Atlanta, United States)
Working perfectly!

Great experience purchasing with Boroux and feel great about my new filters. I had a hard time sourcing but glad I found Boroux. Filters are working faster than old ones purchased from other brand!

Thanks for your reveiw! We're so glad to hear that you are enjoying your new filters and hope that they give you peace of mind when hydrating! Our team is committed to ensuring that you always have a solution for filtering your water by prioritizing product availability. Thank you so much for selecting us to be a part of your water wellness journey!

Suzie Roden (Dallas, United States)


Thanks for selecting us to be a part of your personalized water wellness.

Adele Salvetti (Livonia, United States)
Fit It!

I had a problem with my filter. Boroux reached out to me - how about that. I told them the problem I was having. (No, I don't want to write what it was because there are always those few that jump on and make false claims). They asked me my concerns, did follow ups and solved the problem. Very happy with their customer service and the fact that they reach out to me, keep up with follow ups and fixed the problem. Something not many companies do for a customer that had a problem with their product. This is how business is done correctly. Thank you for caring!

Thank you so much for your kind review. We're so happy to hear that you had a good experience with our team! Our Dedicated Customer Service team is happy to help you through every step of your journey and ensure that you have the latest and greatest in water filtration! Thanks for selecting us to be a part of your personalized water wellness.

Jonah Bookman (Fuquay-Varina, United States)


Thank you so much for choosing us to be a part of your water wellness journey!

Jodi Crosby (Hollywood, United States)
Great product

Easy install and quality check with the red dye, I thought it was going to take longer and put it off for a couple of weeks, but it took about 20 minutes for the whole ordeal.

Thanks for the review! We are happy to know that set up was easy! Thank you so much for choosing us to be a part of your water wellness journey.

Our Story

Building on the legacy of 25 years in the water filter industry, BOROUX embraces innovation and ethical practices. We are committed to quality water. Every drop we filter is a testament to enhancing your well-being. Our dedication to better products, better practices, and better communication leads to you getting better water. BOROUX is the clear choice for hydration.

Learn More About Us


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