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

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 some significant differences – especially regarding fluoride removal and long-term costs.

Bottom Line Upfront

Alexapure - Our Opinion
Alexapure Pro Alexapure Pro

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.
  • While not certified, Alexapure is third-party tested to meet the stringent requirements of NSF/ANSI 42 and 53. You can be sure that the filter removes contaminants even when it is near the end of its lifespan.
Berkey - Our Opinion
Big Berkey Gravity-Fed Water Filter System Big Berkey Gravity-Fed Water Filter System

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.

Quick Comparison

TestingThird-party testedThird-party tested to NSF/ANSI standards
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, which flows through filters. Purified water exits into the bottom tank, where you can access it with a spout.

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

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

What They Treat

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 must buy a separate one. 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 an excellent 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 winner because they are tested to NSF/ANSI standards. Alexapure also meets Prop 65 standards so can be sold in California, whereas Berkey cannot be sold in California.

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), a nonprofit that sets the standards for openness when testing products. The ANSI doesn’t do tests, though. Instead, they accredit other organizations which do testing.

One of these organizations is the NSF.

The National Sanitation Foundation (NSF) is the leading third-party testing organization for water treatment products. They have strict rules about how products must be tested and post test results on their website. Only products that meet their stringent 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.

Does NSF/ANSI Certification Matter?

Virtually all water filters that remove chemicals (including 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 stops working.

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

With NSF/ANSI certification, 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 being tested. 

For example: Alexapure Pro filters have a capacity of 5,000 gallons, which means under NSF standards, they would be tested at 10,000 gallons.

Both Berkey and Alexapure Are Third-Party Tested

Neither Berkey or Alexapure are NSF certified. However, of the two, only Alexapure is tested to meet NSF standards. This was done with a third-party lab and not the NSF.

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 entirely up to the claims.

*Don’t get me wrong. Berkey is still an excellent 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 testing standards.

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, which requires a separate filter on Berkey – meaning the cost of treating water goes up drastically.

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

Initial Investment

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

However, if you want to 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 same.

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

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.


The Berkey filter comes in sizes ranging from 1.5 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 you can put more filters in it, improving the flow rate.

Flow Rate

With Alexapure Pro, you can put one to four filters in the system. The more filters you put in, the faster the filter works. 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 the 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

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

Read our guide to Berkey water filter alternatives.

Buy Online

Both filters are available online; click the links below to check current prices:

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  1. thats not NSF certification. they just claim they are up to NSF standards. True NSF certifications are held on the NSF website and can be found on their pages. They are clearly using a third party company for their results.


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