Water Filter Comparison
...NSF.org Made Easy

Water Filter Comparison

This makes NSF.org an important resource to be used in doing research on different filter models and in making water filter comparison. It is right here that there's a problem. To my way of thinking, and this is coming from a low tech guy, their site is not very user friendly. It is for this reason I have created this page to try and simplify your use of their site. I spent several hours trying to figure out how to find certain filter models and how to understand the information they gave me on those models. I finally ended up calling an NSF representative and talking through some of the mysteries of their site.

I will organize my explanations around some key questions. You may have come with certain filter models to check out in making water filter comparison. The first cluster of questions relate to finding and reading what NSF.org has to say. The second cluster of questions relates to those who have in mind specific contaminants they want to have removed from their water and are wondering which filters are best to remove them. Then I have a final cluster of questions that relate to definitions of terms or clarifications that will help you better use the site.

I. Questions Related to Checking Specific Filters

Question #1: I have a specific filter name and model number that I want to check and find out if it is NSF certified. How do I go about it?

Answer: Go to the page entitled "NSF Product and Service Listings". Near the bottom of the page you will see a box for entering "Model Name or Model Number". You'll just have to try various ways of writing it. Start with just the number or just the model name. If you get nothing and you know the manufacturer, try putting that in the first box on the page labeled "Manufacturer" and look through all their filters to see if your model is there. Another approach is to enter "Product Type". If you know it is a reverse osmosis filter, for example, go through all the filters in that category. It can try your patience just finding models that you know are NSF certified let alone finding ones that may or may not be certified.

Question #2: I have found the filter model, but want to know which standard it is certified for. Is it certified for Standard 42 (aesthetic effects) or Standard 53 (health effects) or Standard 58 (reverse osmosis) or Standard 55 (ultraviolet) or Standard 62 (distillation) or what? Some are certified for two or more standards.

Answer: After finding the model see what it says. If under "reduction claim" it has just a few items including chlorine and "taste and odor reduction" you know it is certified for Standard #42 (aesthetic effects). Then keep going down to see if there is another section entitled, "NSF/ANSI Standard 053". See if your model is listed in this section as well and which contaminants are listed under "reduction claims". Most of the other standards are specific to only one standard. All the reverse osmosis filters that are certified, for example, are under "Product Standard". You will find "Reverse Osmosis...(NSF 58) on the drop down menu. Your model should be listed there with a list of the contaminants that have been effectively reduced under "reduction claim".

Question #3: Exactly which contaminants is this filter certified to effectively reduce?

Answer: If it is certified under Standard 42, it means that the taste and smell is improved. When it says "taste and odor reduction" this would include a reduction of chlorine, chloramine, ammonia, hydrogen sulfite, and metallic tastes, all of which affect taste and odor. If it is certified under Standard 53 for contaminants that affect health, they will list the contaminants which this filter effectively reduces. You can see how critical this is for water filter comparison.

Question #4: What is meant by VOC? What is included?

Answer: VOC stands for Volatile Organic Chemicals. This is a category that includes about 53 man made and naturally occurring chemicals. Some VOCs are pesticides, herbicides, or insecticides that seep into the ground water. Others enter the water through industrial or other waste disposal. You can find the complete list below the list of contaminants given under standard 53 for a filter, if the list contains VOC. In short, when VOC appears in the list it means that the filter effectively removes all these additional 53 chemicals. Whether or not a filter removes VOC's is important in making water filter comparison.

II. Questions on Removing Certain Contaminants

Question #1: I have specific contaminants in mind that I am concerned about removing from my drinking water. How do I find a filter that will remove these?

Answer: It is here that the page entitled, "NFS Product and Service Listings" is particularly helpful. Check off the contaminants you are concerned about in the long list of contaminants provided, indicate the "Product Type" of filter you are interested in, and click "Search". They give you a list of filters that will remove those contaminants which you have indicated.

Question #2: How do I get more information on particular contaminants?

Answer: There is a useful "Contaminant Guide" on the NFS site. You will find clear and useful information about each contaminant you are interested in.

III. Questions on Definitions and Clarifications

Question #1: What is the process that NFS follows in certifying a filter?

Answer: A filter that is certified means that 1) NFS has reviewed the filter by extensive testing to assure that it does what it claims. If, for example, it claims to effectively reduce lead, etc. for 500 gallons, they put those contaminants in the water and test this claim, taking samples periodically to determine if each test meets the standard. 2) They do regular on-site inspections of the manufacturing facilities and analyze the materials used to assure their safety. 3) They conduct annual audits of the filters to assure that they continue to comply with the standards for which they are certified. 4) They assure that the literature promoting the filter is accurate and not misleading. You can see why NFS certification is so critical in water filter comparison.

Question #2: How are filters rated when it comes to the size of particles that they remove? Or, what does a "Class I" filter mean?

Answer: Carbon filters are rated according to the smallest size of particles that they remove. The size is measured in microns. For perspective, a human hair is about 100 microns and a piece of dust is 1 micron. Whole house filters tend to only remove the larger particles (15 microns, or 30 microns). Sediment filters usually come in three sizes: 5, 10, and 20 microns. Carbon block filters will often remove particles down to .5 microns. These are called Class I filters. Class VI filters remove particles down to 50 microns. Part of water filter comparison is taking note of the class of the carbon filter. Following is a table of the classes used by NSF.

Go to "The Question of Filter Certification" for a broader discussion of the meaning of certification and it's role in choosing a filter as you make water filter comparison.

For more information on the whole process of comparing and choosing a water filter go to "Water Filter Comparison".