How Do We Choose the Best Water Filters?

At Water Filter Guru, our goal is to help you identify the best water filter for you, based on our own scoring, reviewing, and ranking. 

We conduct objective data-driven testing to compare water filters and reveal the best products across a range of categories. 

Brian next to the ZeroWater Glass Dispenser

Objective Testing Data

Rather than using generic information online, we test water filter performance using our own framework, combining multiple data points to assign scores to water filters in each testing category. 

Our testing categories include: 

  • Contaminant Reduction
  • Filtration Rate
  • Design
  • Setup 
  • Maintenance
  • Company

You can see how each category contributes to the total score in the next chart. 

scoring factors

Our testing goes into minute detail and our scoring system is based on real data, so we can provide a transparent and equitable quantitative evaluation of water filters. We’ve gone into the nitty-gritty on how we test and score water filters here


For some of our best guides, it’s relevant for us to consider different applications. We may recommend different products for different applications, such as point-of-entry whole-home systems, and various point-of-use systems, which appeal to different folks in different situations.

Kind E-1000 filter cartridges

We also look at the specific use case. For instance, we have produced numerous guides on the best water filters for reducing specific contaminants in water. In these guides, the best systems are those that reduce the highest concentration of the contaminant in question.

For these articles, we focus on how well a water filter meets the requirements of a specific use case. Let’s say that a water filter has a better overall score for contaminant reduction based on the Tap Score algorithm, but it doesn’t reduce the specific contaminant as much as another system we’ve reviewed. This could influence how the filter is ranked for the guide, as we’ll prioritize its relevance for reducing the specific contaminant rather than its contaminant reduction on the whole. 


  • Product A receives an 83 score for contaminant reduction and product B receives a 95.
  • Product A reduced 100% of fluoride while product B only reduced 25%. 
  • Outcome: We’ll recommend product A over product B on our “best fluoride filters” list.

Technology Type

When it makes sense to do so, we may also choose to include different systems in our guides based on different technology. 

For example, we know that some folks don’t like reverse osmosis systems, so, when we can, we’ll make sure to include a regular countertop or under-sink filtration system in addition to reverse osmosis systems in a guide.

This ensures we’re presenting options for everyone, regardless of preference, when multiple systems are available to achieve a similar desired outcome. 

Cost & Value

We know that budget plays a part in our readers’ buying decisions, so we also consider cost and value for money when deciding on which water filters to recommend. 

For example, if two water filters obtain very similar performance scores, but one costs $200 and the other costs $500, we are most likely going to recommend the more affordable option because it offers the best value for money. 

We’ve tested dozens of water filters to date, which means we’ve obtained the data to confidently say whether or not we think a water filter is good value for money based on its performance, technology type, and application.

For instance, we may determine from our previous testing that the majority of water filter pitchers fall within the $25-$50 price range. So, if we test a pitcher that costs $80, we take the time to examine what (if any) additional value the filter offers that makes it worth its higher upfront cost. 

Water filters also cost money to maintain, so ongoing spend is an equally important consideration when determining a filter’s overall value. 

Brand Reputation

We know that our own experience using a water filter has its limitations, and, although we test as thoroughly and objectively as possible, may not tell the full story. 

That’s why we only recommend water filter brands that have a proven reputation for reliability, both with the quality of their products and with the consistency of their customer service. 

We want to be certain that a company has earned the trust of its customers, so we can confidently recommend the brand with no reservations of our own. 

In our opinion, signs of a trustworthy and reputable brand include: 

  • Certified products
  • Honest product descriptions with no deceptive marketing tactics 
  • Responsive and helpful customer service
  • Quality product materials and build
  • Fair & transparent warranty & returns policies 

We don’t feature a water filter in any of our “best” guides unless we trust the manufacturer, and we have real evidence to show that the manufacturer is trusted by customers on the whole. 

However, it’s important to acknowledge that we occasionally review up-and-coming water filter manufacturers that may not have a long history of providing reputable customer service, which may impact their trustworthiness. 

Ensuring Variety

Where possible, we try to ensure variety when recommending water filters for our guides. 

So, if a brand sells two water filters that we think are both suitable for achieving a specific end goal, we’ll primarily review the brand’s best filter offering, then mention the subsequent filter as an alternative option within the same review. 

Water filter pitchers sitting on a countertop

The same goes for brands that offer different models or configurations for the same water filter. 

For example, the AquaTru is a countertop RO system that’s available in four different models. Rather than reviewing the different models separately, we’d discuss our top favorite of the four, then mention one or several of the other models as possible options for slightly different outcomes and budgets. 

Product Availability

We want to provide the most relevant and convenient water filter recommendations to our audience, which is predominantly US-based. 

So, all of the water filters we test and review are available in the United States. Some may also be sold in other regions, but our priority is to ensure that we’re recommending products that are available to most of our readers. 

We also don’t review products sold only within a specific region (city or state) that aren’t available nationally. 

Also on the subject of product availability, we keep a close eye on stock for the water filters we review. Water filters that are frequently unavailable or out of stock don’t often make our top picks unless we’re made aware of a temporary supply issue. 

While we may occasionally review products that can only be purchased from a specific dealer in person, our focus is on providing the greatest value to as many people as we can. So the overwhelming majority of the water filters we review are available to buy online. 

Our Impression 

We make every effort to ensure our recommendations are based on our objective data, but ultimately, our own input goes into choosing which water filters do and don’t feature in our reviews.

Brian holding the black berkey filter element

For instance, there are some occasions when we may choose not to recommend a water filter, even if its performance scores are quite high. We may exclude a product from our list if we’ve noticed differences in performance, quality, or company offerings (warranty, shipping, etc.), or simply because two products are tied in the same category. 

We may also choose to mention a water filter at our own discretion even if it didn’t quite make the cut, based on our belief that it’s worthy of being included in the particular guide. 

Regular Updates 

The water filter market is booming. Dozens of new products are released every year, bringing new technology and innovations to the table.

As the industry evolves, we ensure that we do too. 

We regularly revisit and update our guides, ensuring that we’re still recommending the best products from the market offering. We check our existing reviews for accuracy, ensuring that a filter’s design, processes, and pricing haven’t changed. 

Our priority is ensuring that a water filter continues to meet our high standards and serve its intended purpose. We occasionally remove products from our roundup guides if they fail to do so. 

We keep an eye on what’s new and trending, and we test all the products that we think have a chance of competing with our existing recommendations.  

Our aim is to continue to populate our reviews and guides with the best-performing and most relevant water filters for our readers at any time.

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