WQA & NSF Certified Water Filters

Looking for an NSF 53 certified water filter? We discuss the different NSF and WQA standards, and recommend some water filter systems that have these accreditations.


Water filter manufacturers are like any other companies trying to sell their products, and they are prone to exaggerations about their systems. The figures they give for water production rates and lifespans of filters are achieved under optimum conditions, and will often not match up with your experience.

However, the most important figures are those which concern a water filter’s effectiveness in protecting your water. Companies commonly boast of “99% lead reduction” or “95% of chlorine removed”, so how do we know whether to believe these figures, if others are sometimes fanciful?

Luckily, the Water Quality Association (WQA) and NSF International are at hand. These are independent organizations that test and certify water filter systems and components. Water filter systems that carry these logos are proven to deliver on their promises.

Today, we take a deeper look into what these standards mean, and find out which are the best certified water filters

NSF Certified Water FiltersNSF-certified

NSF International provide certification to prove that water filters remove specific contaminants to a standardized level.

So what does ‘NSF certified’ mean to a water filter?

In a nutshell, an NSF certified water filter is one that…

  1. … is structurally solid.
  2. … is built from approved plastics and components that won’t leach into the water (like BPA plastic).
  3. … is built from materials that will last.
  4. … has approved labels that are 100% true.
  5. … has test results that are 100% facts.

One thing to look for with the NSF certificates is that sometimes they will only relate to specific parts of the water filter system, or specific contaminants that they reduce. Sometimes water filter manufacturers imply that their systems are fully certified in every aspect, when in fact they only meet one specific safety standard.

There are many different NSF certifications. Today we will look at:

  • NSF 53
  • NSF 58
  • NSF 42
  • NSF 401

We will discuss each specific NSF safety standard, and what it actually means. We’ll also give examples of some of the best NSF certified water filters, that meet each of these standards.

NSF 53 / NSF 58

NSF 53 certified water filters meet the minimum safety requirements to reduce specific harmful water contaminants.

These contaminants include:

  • Lead
  • Cryptosporidium
  • Giardia
  • Volatile Organic Compounds (VOCs)
  • Methyl Tertiary Butyl Ether (MTBE)

The NSF 53 safety standard includes the structural integrity, material safety, and the contaminate reduction performance claims. It typically relates to water filters that use carbon absorption as a means of filtration. The removal rate of water filters that meet this standard can vary. The NSF standard means that the water filter meets a minimum threshold. You would have to consult the filter’s performance data sheet to get exact figures.

NSF 58 is a safety standard for lead, and other common contaminant removal too. Instead of carbon water filters, it relates to water filters that use a membrane, like reverse osmosis systems (RO).

In our opinion, the best NSF 53 certified water filters are the following:


This certified water filter pitcher is one we speak very highly about in our guide. It is an NSF 53 water filter that will remove lead (and other contaminants). It is also NSF 42 certified (more on that later) to remove chlorine.

It’s an impressive pitcher that offers a level of filtration that other jugs can’t match. It’s also a rare breed of water filter that will remove fluoride in water too. This means the filters are a bit more expensive than average. But if you’re getting standards 42 and 53 NSF certification and fluoride reduction then you can justify the cost.

PUR-3-Stage-Horizontal-Faucet-Mount-Chrome-FM-9400BPUR-3-Stage-Horizontal-Faucet-Mount-Chrome-FM-9400BPUR 3-Stage Faucet Mount

This faucet mounted filter meets NSF/ANSI Standard 53 for the reduction of contaminants such as lead. It’s a system that we highly recommend in our faucet water filter guide.

It’s another that is very competitively priced, and very easy to install and maintain. This is one of the cheaper NSF 53 certified water filters.

Aquasana-AQ-RO-3.56-OptimH2OAquasana OptimH2O

This NSF 53 water filter from Aquasana has an amazing level of accreditation. It is tested and certified to meet standards 42, 53, 58, and 401. It’s the only water filter that I am aware of that can boast such a thing.

Meeting such a range of standards makes this one of the best NSF certified water filters around. It is also a rare reverse osmosis system, as it uses carbon filtration as well as the special membrane.

Being an RO system, this needs to be installed under the kitchen sink. The installation isn’t complicated, but it will require some DIY skills.

Reverse osmosis systems offer the most powerful form of water filtration available in the home.

NSF 42

The NSF 42 standard relates to a water filter’s ability to remove chlorine from water. However, NSF 42 certification does not include the harmful chlorine by-products. Like many standards, water filters can meet or exceed this standard to different levels of effectiveness. It is a base line of chlorine reduction.

This is one of the best NSF 42 certified water filters:

Woder-10K-GenIIWoder 10K Under-Sink

This is certified to remove huge amounts of lead and chlorine.

It’s installed under the sink, but is quite simple to set up. It can last for 3 years before you need to change the filter, which makes it very easy to look after.

It also comes very highly recommended on Amazon.

NSF 401

NSF standard 401 is a new standard that rates the ability of a water filter system to reduce up to 15 separate contaminants. These contaminants have been found by scientific studies to be present in some drinking water.

It typically deals with unnatural chemicals like pharmaceuticals, BPA, herbicides, and pesticides. These are new and emerging pollutants that come from industrial processes and farming. This standard applies to carbon and RO water filter systems.

Aquasana-AQ-4000W-Countertop-Water-Filter-System-200pAquasana AQ-4000

This countertop system actually meets NSF standards 401, 42, and 53. In doing so, it removes a wide range of harmful contaminants.

Being a countertop unit, it is really easy to install and maintain too.

It’s very reasonably priced, and is well regarded in Amazon reviews.

WQA Certified Water Filters


The WQA offers a Gold Seal Certificate to show that a water filter system “is constructed or formulated from safe materials, the claims listed on the packaging are backed by test data, and the product will hold up under normal usage conditions.”

This means that if a model that has been WQA certified is stated as removing 98% of lead from your water, then you can have confidence in the fact that it will do exactly as it says.

An example of a WQA Gold Seal certified system is the iSpring RCC7AK.

ispring-rcc7ak-200piSpring RCC7AK

This RO system is certified to remove a huge range of contaminants. RO is a very powerful method of water filtration, and this is one of the best models out there.

This particular system also has an alkaline filter that adds healthy minerals to the water. This means great tasting, contaminant free drinking water for the home.

Final Thought

I would recommend always looking for, or asking about these certifications. If a water filter system is certified in one of these ways then you can be assured of its quality, and relax in the thought that your drinking water is in safe hands.

However, none of these systems claim 100% contaminant rejection rates. The NSF & WQA standards mean that a system meets minimum requirements under independent testing. The manufacturers should have the actual documentation or results as public information. You should check this out to find out whether a certified water filter removes 99% of chlorine or 90%, for example.

An example of a performance data sheet for the Aquasana AQ-4000 that we mentioned earlier can be viewed here. It shows the level of rejection for each specific contaminant, and an overall pass/fail result.

Also note that these are not the only authorities that provide independent testing. They are the most well known, and authoritative, but other ways exist. Some smaller manufacturers gain certification from smaller independent laboratories.

Most of the more well known companies (APEC, iSpring, Aquapure, Aquasana etc.) will always produce units that are NSF/WQA certified. Be vigilant if you are on a tight budget, and make sure you see some form of certification/accreditation, be it from the big names or a smaller lab.

If you’d like to know more about buying water filters then please read our guides for reverse osmosis and whole house water filters. If you’re not sure where to start then our guide to choosing the right water filter is a useful resource too.

If you would like to keep up to date with the latest news and events in the water filter world, and also the latest on the environment and water pollution, then check out our Facebook page. There’s a link at the top of the page.

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