Water Purifier or Water Filter – Which is Best?


To know which one is the best (a water filter or water purifier), it’s about the phrasing, words, and how it relates to water treatment standards.

The term ‘water filter’ is broadly used to describe many water filtration devices. But did you know that not all water filters are alike in their ability to reduce pathogens (a virus, bacterium, or other microorganism)?

Not only that, but there is a difference between the meaning of water filter and water purifier when it comes to actual water treatment standards.

Lets take a look at the two standards when classifying water treatment devices:

According to the Environmental Protection Agency (EPA), “Guide Standard And Protocol For Testing Microbiological Water Purifiers” (source),

To distinguish a water purifier from a water filter:


Water Filter

Classification of ‘water filter’ – the filtration device must meet this standard:

Contaminant: Pathogenic Bacteria
Removal standard: 99.99% minimum reduction, also known as (Log 4)


Water Purifier

Classification of ‘water purifier’ – the filtration device must meet this standard:

Contaminant: Pathogenic Bacteria
Removal standard: 99.9999% minimum reduction, also known as (Log 6)

Plus this…

Contaminant: Virus
Removal standard: 99.99% minimum reduction, also known as (Log 4)


A Water Purifier is Best

A water purifier must filter out Bacteria to Log 6 and Virus to Log 4.

Most of those water filter pitchers that you might keep in your fridge, or the water filters that attach to your faucet, are water ‘filters’. Meaning that they filter out some pathogens.

But there are other choices that are actually water purifiers. They will remove a much greater extent of bacteria (plus viruses).

When comparing and deciding about water filters, pay attention to the reduction (99.9999% vs. 99.99%) (and/or Log #’s).

The best water filters / purifiers will remove a higher percentage of pathogens and/or virus. Note that a water ‘filter’ doesn’t have to remove any virus at all.

Note: Fortunately virus in our water here in the U.S. is not really an issue.


A High Quality Water Purifier

A water purifier which I consider to be one of the best is the Berkey. All Berkey systems now contain the Black Berkey Filter elements. And they meet the Water Purifier standard. In fact Berkey Purifiers surpass the ‘purifier’ standard.


Black Berkey Filter Specs

99.9999% reduction (Log 6) of pathogenic bacteria
99.999% reduction (Log 5) of viruses

Big Berkey

This distinction actually makes Berkey the only certifiable gravity flow water purification system on the market (that I know of).

I have been using Berkey for many years. All of our drinking water is purified with their filters. Our bodies are made up of about 75% water. I figure it’s pretty important to take steps that the water we’re drinking is clean and purified!

Also, by having a good quality water purifier, I know that in any emergency situation I could easily purify water from other questionable sources that may contain pathogens, bacteria, or even viruses.


Invest in your Health

I believe that a quality water purifier is a very high priority investment for overall preparedness. From time to time I post an article about this (because I believe it’s so important). I tend to ‘push’ the Berkey (because I have long term experience with it) and can vouch for it.

I really like the stainless steel Big Berkey countertop gravity filter for the house. Clean pure water is always readily available with a press of the spigot handle…

Tip: The Travel Berkey is a great alternative and compact in size for a countertop model. It uses the same filters. (Here are the specifications)

The initial investment of any quality product is expensive. But that expense is ‘relative’ when you consider the need for purified drinking water during an emergency situation! Not to mention the everyday health benefit from day-to-day use.


Most Popular Berkey Water Purifier

Big Berkey - 2 gallons

Are you on a well? (I am), it’s a good investment!

Even on municipal water, you never know what might happen…

Big Berkey Water Filter System

Tip: How To Clean Berkey Water Filters

Tip: This is a really interesting perspective on the ‘size of things’ when we’re talking about bacteria and virus: Cell Size and Scale (from utah.edu)