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LifeSaver: How to choose a portable water filter or purifier

How to choose a portable water filter or purifier

How to choose a portable water filter or purifier

Posted 5 years ago



A question we are often asked is, ‘Why should I buy your product?’. We love this question, as it gives us the chance to explain things in detail to our potential customers. The consequences of drinking contaminated water can be life threatening, so the main thing you should look for in a portable water filter or purifier is SAFETY. The following information should help you make the safest choice.

Now unless you walk around carrying a water quality testing kit at all times, you can never really know for certain what is in the water you’re drinking. The thing about bacteria, protozoa (cysts) and virus is that you can’t see them! So the safest thing to assume is that an unknown water source could have anything in it.

There are numerous products on the market that claim to filter or purify water, alleging to make it safe to drink. The scary truth is, this industry is unregulated. A manufacturer can make any claims about their products that they want to, they don’t even need to have their products tested!

To make sure you aren’t caught out and can make an informed decision, here are 6 essential questions you should ask. We’ve even provided the answers for you!


1. What is the difference between a portable water purifier and portable water filter?

A water purifier removes, kills or inactivates all types of disease-causing microorganisms, such as bacteria, viruses and protozoan cysts, making water safe to drink.

A portable water filter only removes bacteria and protozoa, but NOT virus, which are far smaller. You would likely get very sick using a water filter to treat water which contains virus.

So it’s fair to say water purifiers are a safer option than water filters.


2. What standards do manufacturers need to meet in order to sell a portable water filter or purifier to the public?

None. There is nothing stopping someone from making a water filter out of an old sock, claiming it rids the world of disease and selling it to the masses. The ‘portable water filtration’ industry is completely unregulated and as a result, there are many embellished, misleading and unfounded claims made.

So don’t trust everything you read. #Fakenews


3. What should consumers look for to know if a product can be trusted?

The most important thing to look for is evidence of credible testing. The manufacturer should have a ‘certificate of testing’ for each product in their range, demonstrating they have met appropriate standards. The testing certifications should be available to view on their website (preferably) or upon request. Ask yourself this, if a company has tested their products, why wouldn’t they show the results?

So manufacturers should show that their products are tested to appropriate standards.


4. What are appropriate standards for water purifiers to be tested to?

This is the crux of the matter, and where the following knowledge can keep you safe. Warning, if you weren’t already bored, this next bit should do it!

*Takes deep breath…

The EPA (Environmental Protection Agency) Guide Standard Protocol was written in 1987 for testing microbiological water purifiers. This became the gold standard, determining what level of reduction of virus, bacteria, and protozoa is needed before water is safe to drink. The next organisation to throw their hat into the ‘drinking water standards’ ring was NSF (National Sanitation Foundation), who produced their own recommendation, the ‘NSF P231 microbiological water purifiers protocol‘. This is based on the original EPA guidelines, but gets revised more regularly, allowing for new technologies and organisms for testing with.

water being tested in a scientific laboratory.

The full NSF P231 protocol requires tests be carried out on two different types of water over an 11 day period (or the life of the filter, whichever ends first). For the first six days, the filter is tested with General Test Water (Type 1). This is just ‘spiked tap water’ – designed to test how the filter would cope with viral and bacterial contamination in your tap water supply. This should be a breeze to pass.

The real challenge comes in the final five days, when the Type 1 water is replaced for Challenge Test Water (Type 3). This Type 3 water is dirty, cold, PH adjusted, has dissolved solids and organic matter mixed in, and of course includes plenty of virus and bacteria! It’s designed to represent the worst case scenario you could come across in the real world. It’s practically sewage water. Whether hiking in the back country or travelling through developing countries, wouldn’t you sleep easier knowing your purifier product has had hundreds of litres of the worst possible water put through it and passed with flying colours?

Worryingly, most water filters and purifiers sold in stores cannot complete the second half of the NSF P231 protocol with the Type 3 Challenge Test Water. Therefore, most products out there aren’t actually tested to the real-world standards that you will be using them in!

Now here’s where things get even murkier (like Type 3 water murky!). Some manufacturers claim to meet or exceed EPA guidelines & NSF P231 standards. However, they have only completed the Type 1 water phase of the protocol, they haven’t completed the Type 3 stage of the 11 day test. For example, there’s actually one water purifier brand who show their testing certificate online, and the certificate states that the test was only carried out on 1 litre of water! So no one knows how effective that product is beyond that first litre!


Also look out for filters or purifiers claiming to meet ‘NSF 42 & 53’ standards. These standards are for ‘health and aesthetic taste effects for RESIDENTIAL water filters’. All this test proves is that they are suitable for filtering water from the tap in your home. They will not remove bacteria and virus!

So the NSF P231 standard is the only test worth its salt. It’s very difficult to pass, involving 11 days testing with Type 1 and then Type 3 waters. That is the standard your purifier should be tested to and meet. If there is no mention and evidence of NSF P231 or EPA guide testing, question why.



Testing should always be done through an external independent Lab. The lab should be ISO 17025 accredited, ensuring it is competent and follows best practice. Here are some labs which meet this criteria and have the relevant experience with testing drinking water.

  • NSF (National Sanitation foundation) Ann Arbor, Michigan, USA
  • BCS (Biological Consulting Services) Gainesville, Florida, USA
  • Biovir Laboratories California, USA
  • WQA (Water Quality Association) Illinois, USA
  • SGS Worldwide locations
  • Multiple University laboratories worldwide (with relevant faculties)

So if the Laboratory referenced in a testing certificate isn’t one of the above, perhaps do some further digging to ascertain its credentials.



By now you know, if a product claims to be a water purifier, it tackles virus, in addition to bacteria and cysts (protozoa). There are two methods commonly used to purify water in portable purification products. One uses ‘hollow fibre membranes’ which basically act as a physical barrier, catching microorganisms while letting water pass through. The second method involves using an element which chemically reacts with the contents of the water.

Hollow Fibre Membranes: The size of the ‘pores’ (holes) in hollow fibre membranes is what is important. The size is crucial, because the pores must be smaller than whatever we intend to block out. Most water filters use hollow fibre membranes with a pore size of 0.1 or 0.2 microns (100 or 200 nanometers). At this size, they will safely block out protozoa and bacteria, but virus are much smaller and would pass through these pores. Some waterborne virus can be as small as 0.02 micron (or 20 nanometers).

The membranes we use in our LifeSaver purifiers have a pore size of approximately 15 nanometers or 0.015 microns. So our membranes are like a tennis racket, rain (water molecules) can pass through, but the tennis ball (smallest waterborne virus) cannot get through.

A tennis ball hitting a racket illustrates how hollow fibre membranes physically block virus, bacteria and protozoa in water purification

The real beauty of using hollow fibre membranes is that, as the product is used, the pores begin to block up. Eventually every single pore will be blocked and even water molecules won’t pass through. Whilst this seems like a downside for the user (as they’ll need a replacement cartridge), it’s incredibly important to have a visible sign that your product isn’t working anymore. At least you can’t drink dangerous water from a LifeSaver product if it stops letting water come through! It’s because of this feature, coupled with the fact we block virus and are fully tested to NSF P231 standards, that we call our products FAILSAFE.

Adsorptive Technology: Remember that second method we mentioned? Well, some water purifiers rely on using elements to have chemical reactions with contaminants in the water. This element effectively creates an attraction, a bit like when someone’s hair is attracted to a balloon because of static. As the water passes through, the contaminants in the water are drawn to the element and stick to it, meaning only safe water passes through to the user. That’s great in the short term, but unfortunately it doesn’t take long for the element to lose its level of attraction. As the element gets more and more contaminants stuck to it, it becomes less and less effective, especially with turbid or cloudy water. Products using this technology would struggle with Type 3 water. The short term effectiveness of these products is exactly why some companies only test the first 1 litre!

Hair attracted to a balloon due to static illustrates how adsorptive technology is used in water purification

However, the real danger with products using adsorptive technology is that once the element stops attracting the harmful contaminants, there’s no physical barrier to block them from passing through the user. To make matters worse, there’s no way for the user to know when the element has reached that point! This is why some water purifiers will claim to remove virus for just 100 litres (not very much at all) or even suggest replacing the element every few months. This leaves the customer having to either keep count of the number of litres they’re drinking, or remember how long ago they replaced the element. Not very practical and not very safe!

So products using adsorptive reactions aren’t effective for very long. The user can’t tell when they’ve stopped purifying water effectively, so therefore you’re gambling with your health. While LifeSaver water purifiers use hollow fibre membranes which eventually block up, protecting the user.



Because our products were designed to be used by vulnerable people in developing countries or following disasters, we had to ensure they had these innate characteristics:

  • Must be portable
  • Must not require chemicals or electricity
  • Must remove all types of microorganisms (including virus)
  • Must be FAILSAFE (never let unsafe water pass through)

It’s because of the last two points that we pride ourselves on having the safest water purifiers you will find.


Let’s leave you with one last question, and you can answer this one for yourself.


Why would you take a chance on your health?

mic drop, after delivering a compelling case for LifeSaver water purifiers being the super safest products in the market

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7 thoughts on “How to choose a portable water filter or purifier”

  1. It’s great that you talked about water filters and how to make sure they’ve been tested before selling them. Last week, my sister said her house’s water tastes weird, so she wants to buy a purification system to fix it, and I think your tips will help her find a high-quality one. Thanks for the advice on water filters and where we could find their testing certificate.

  2. I like what you said about how hollow fibre membranes have a pore size of .1. I need to get a water filtration system installed on my property. I am just too scared that my water has too much mercury in it.

  3. I love your tip about how a purifier kills all the bacteria. My wife and I are thinking about buying a barn and might need to get a water filter. I’ll have to consider your tips and get something that eliminates all the bacteria.

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