Berkey vs. Alexapure Pro: Performance, Cost and Reliability Analysed

Last Updated: February 7, 2022

At first look, the Berkey and Alexapure Pro water filters seem almost identical.  In many ways, they are the same.

However, when you look more in-depth, you’ll find that there are some important differences – especially when it comes to fluoride removal and long-term costs.

Bottom Line Upfront


We prefer the Alexapure for these reasons:

  • When you calculate fluoride removal, the Alexapure ends up being much cheaper in both the short-term and long run than Berkey filters.
  • Alexapure meets the stringent requirements of NSF/ANSI 42 and 53, so you can be sure that the filter removes contaminants even when it is near the end of its lifespan.

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Choose Berkey If:  You don’t care about fluoride removal, don’t have a known issue with your tap water, and have a large family. The larger size systems filter much faster and end up being cheaper if you don’t bother with the fluoride filters.

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Quick Comparison

TestingThird-party testedNSF/ANSI certified
Removes203 contaminants including: Bacteria, parasites, viruses, heavy metals, lead, and pesticides206 contaminants including: Bacteria, parasites, viruses, heavy metals, lead, and pesticides
Removes fluoride?Requires separate filterRemoves fluoride
Filter life3,000 gallons per Black filter5,000 gallons per filter
Flow rate1-6.5 gallons/hour*1-4 gallons/hour*
Sizes (Raw water capacity)1.5, 2.25, 2.75, 3.25, 4.5 and 6 gallons2.25 gallons
Dimensions (2.25 gallon size)13” (H) x 8.5” (W)14” (H) x 10” (W)
Weight (2.25 gallon gize)7lbs7.6lbs
Made fromStainless steelStainless steel
Filters manufactured inUSAUSA

*Flow rate is faster when more filters are used

How They Work

Berkey and Alexapure Pro are both gravity water purifiers.  They both are made up of a stainless steel top tank which nestles into a bottom tank.  You put untreated water into the top tank where it then flows through filters.  Purified water exits into the bottom tank, where you can access it with a spout.

Neither Alexapure nor Berkey are very forthcoming about how their filters work (their websites use a lot of high-tech scientific words to describe the filters but don’t actually list the exact technology).

However, based on what the filters remove, we can assume that both use a combination of technologies.  These likely include a hollow-fiber filter and activated carbon.

What They Treat

big berkeyAlexapure

Berkey Black filters and Alexapure Pro filters both treat a huge number of potential contaminants, including:

  • Viruses
  • Bacteria
  • Parasites
  • Heavy metals
  • Chemicals like chlorine, pesticides and herbicides
  • Pharmaceutical drugs

The big difference is that Alexapure removes fluoride and arsenic from water.  If you want to remove these contaminants with a Berkey filter, you have to buy a separate filter.   This filter is quite pricey and needs to be replaced more often than their Black filters.


Berkey and Alexapure are both trusted brand names and have a very good reputation for doing what they say they do.

Both brands post-test results on their websites to back up their claims.  However, when it comes to reliability, Alexapure is the clear winner because they are NSF/ANSI certified.

What Does NSF/ANSI Certification Mean?

Because there are no laws regulating water filters or their claims, private organizations have stepped in.

The first is the American National Standards Institute (ANSI), which is a nonprofit that sets the standards for openness when testing products.  The ANSI doesn’t actually do tests though.  Rather, they accredit other organizations which do testing.

One of these organizations is the NSF.

Currently, the National Sanitation Foundation (NSF) is the leading third-party testing organization when it comes to water treatment products.  They have very strict rules about how products must be tested and post test results on their website. Only products which meet their strict requirements will get NSF certification.

The NSF has different requirements depending on the type of water filter.  You can read an overview of them here. Alexapure Pro meets NSF/ANSI standards 42 and 53.

Does NSF/ANSI Certification Really Matter?

Because Berkey publishes third-party lab test results on their website, you might think that NSF/ANSI certification doesn’t really matter.  However, the fact that Alexapure has the NSF/ANSI certification means it is likely a much more reliable product.

Here’s why.

Virtually all water filters which remove chemicals (which includes both Berkey and Alexapure Pro) use adsorption technology such as activated carbon.  The problem with adsorption technology is that, as the filter reaches its capacity, it eventually stops working.

In fact, your water filter might even start leaching out all of the chemicals it previously absorbed.

With NSF/ANSI certification though, you can trust that the filter will work for its rated life: under NSF standards, all products must pass through twice their rated capacity before they are tested.  Alexapure Pro filters have a capacity of 5,000 gallons, which means the NSF tested them at 10,000 gallons.

Even though Berkey posts lab results, we don’t know if these tests were done with a new filter or one near the end of its lifespan.   We also don’t know how many contaminants were in the test water before filtering.  Thus, it is no surprise that some Berkey customers who did their own tests found that the filters didn’t live completely up to the claims.

*Don’t get me wrong.  Berkey is still a really good filter and one of my favorite water filters for survival. However, when comparing Berkey with Alexapure Pro, the Alexapure filter is more trustworthy because of the NSF/ANSI certification.

Cost of Berkey vs. Alexapure Pro

When comparing the cost of Alexapure Pro with Big Berkey (which is also 2.25 gallons in capacity), the Berkey system is slightly cheaper per gallon of water treated. However, if you also want to treat fluoride in water, the Alexapure Pro filter is much more affordable.

How I Compared Costs

You can’t directly compare the costs of Berkey and Alexapure Pro because their filters have different capacities.  On top of that, Alexapure Pro removes fluoride whereas that requires a separate filter on Berkey – meaning the cost of treating water goes up drastically.

To get an accurate cost comparison, I divided the cost by gallons treated.

Initial Investment

The Big Berkey comes with two black filters (capacity of 6,000 gallons) whereas the Alexapure comes with one filter (5,000-gallon capacity).   When you break it down this way, Big Berkey is the more affordable choice.

However, if you want to also remove fluoride with the Berkey system, you’ll need 6 fluoride filters (each has a capacity of 500 gallons). When you calculate the high cost of these filters, the price of your initial investment increases drastically.

Ongoing Costs

You’ll eventually need to buy replacement filters for your Berkey or Alexapure Pro.  When you break it down by gallons treated, the Berkey and Alexapure filters cost almost the exact same.

However, remember you’ll need 6 fluoride filters per 1 Black filter if you want to remove fluoride with your Berkey.  When you calculate this extra expense, the Berkey system is approximately 4x more expensive than Alexapure Pro.

Initial CostCost Per Replacement Filter
Big Berkey with Black Filters$0.046 per gallon$0.021 per gallon
Big Berkey with Black and fluoride filters$0.114 per gallon$0.089 per gallon
Alexapure Pro$0.054 per gallon$0.024 per gallon

 *Note that these cost estimates can change depending on current prices, whether products are on sale, and whether you buy filters in bulk.


Alexapure probig berkey

The Berkey filter comes in sizes ranging from 1.5 gallons up to 6 gallons.  By contrast, the Alexapure Pro is currently only available in 2.25-gallon sizes.

Berkey’s Go and Travel size filters are very convenient for people who move around a lot (they are particularly popular in the RV living world).  As for home usage, almost everyone I know who has a Big Berkey for their home says they regret not getting a larger size.  A larger size means that you can put more filters in it and the flow rate improves.

Flow Rate

With Alexapure Pro, you have the option of putting one to four filters in the system.  The more filters you put in it, the faster the filter will work.  With four filters in, you’ll get a flow rate of about 1 gallon per hour.

Berkey also has the option of putting just one or multiple filters in their systems.  The larger size systems can hold up to 6 filters, which means a flow rate of up to 6.5 gallons per hour. That is much more convenient for large families who drink a lot of water.

Also bear in mind that the weight of the water affects flow rate: as the top tank empties, it will start to flow slower.  So, if you start with a larger tank, you’ll get water faster.  Hence why so many people regret not getting a larger Berkey system.

Berkey Max Filters:

SystemCapacityMax Filters
Crown6 gallons8
Imperial4.5 gallons6
Royal3.25 gallons4
Light2.75 gallons4
Big2.25 gallons4
Travel1.5 gallons2
Go1 gallon1

The bottom line is that, if you have a large family, it might be worth getting a larger Berkey system instead of the Alexapure Pro.  You’ll really appreciate the faster flow rate!  Otherwise, the Alexapure Pro is a better value and more reliable.

Buy Online

Both filters are available online at Amazon, click the links below to check current prices:

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  1. According to all internet sites, neither Alexapure nor Berkey are NSF certified. Please provide info or the website showing that Alexapure is certified.


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