Microns Defined: Understanding Your Whole House Water Filter

What are microns and how important are they to your filtered water?

This is what you know: water goes into your home through your filter, and clean, healthy water pours into your glass. You know that when your drinking water has gone through a reliable whole house water filter system, you don’t have to worry about unseen chemicals, bacteria, or pesticides getting into your body either through your drinking water or via inhalation from your shower. That’s great news! 

But your whole home filter system is a fully functional ecosystem on its own, with many moving parts. And when it inevitably comes time to replace your filter, understanding each function can get confusing – fast.  

So, let’s start with the basics.  


A “micron” is a unit of measurement of the size of a unit of water contamination. So, then, a micron level is the number of micron sizes that the filter can eliminate contamination. Micron levels in water filtration are usually between .5 and 5 microns.  

For example, a human hair is as large as 70 microns. A piece of household dust can be 40 microns, and white blood cells can be as small as 25 microns. If your filter removes particles smaller than 5 microns, it can reach particles as small as lead. Funny how something so small can make such a large impact on your body, your health, and your peace of mind.   

If your filter removes particles smaller than 5 microns, it can reach particles as small as lead.

But this is just a part of a whole, so how does this play into your whole home filter system? 


As we’ve covered on our previous blog, whole home filters typically involve a three-step process in filtering your water from bacteria, sediments and silt.  

First, you’ll start with the pre-filter process that works to remove larger particulates, impurities, and contaminants found in your tap water. Keep in mind the size of the particles that it microns_blog_bodyremoves at this stage – many sediment pre-filters are equipped to handle silt down to 1 micron. 

Then, you’ll go into the Carbon Block. This includes a carbon and zinc mineral stone that works to reduce chlorine and chloramines from your water that your municipality uses to treat the water at the water treatment plant. Chlorine and chloramines often have remarkable staying power, and can damage skin and hair, as well as be a cause for concern for those who suffer from asthma.  

After that, you’ll go to the activated carbon filter stage. It’s at this stage that your water filter works to reduce herbicides, pesticides, and more. In the Aquasana OptimH2O Water Filter System, the main carbon block filters down to 0.5 microns to tackle lead, cysts, PFOA/PFOS, chlorine, chloramines and more all in one swoop. 

Finally, post-filter acts as a polishing agent to catch any remaining sediment in your water.  

Micron levels played a key role at every stage of the process. They’re what makes whole house water filters such worthy investments. 


We touched on this a bit earlier, but the lower the micron number, the more contaminants caught and purified from your waterSo be sure to pay extra attention to the micron level when you are researching or looking to purchase any carbon filtration water filter.  

Charcoal filters are the most popular filtration systems, commonly used in whole house filtersunder sink drinking water filters, and shower water filters. These types of filters work the same way as a carbon filter, except the contaminants pass through charcoal instead of carbon. Micron levels are also present in a charcoal filter. 

If a charcoal filter can stop anything 1-micron level or lower, the filter is most likely to be able to filter out cryptosporidium and giardia. Both cryptosporidiosis and giardiasis are caused by these parasites that affect the small intestine and can result in symptoms like diarrhea, dehydration, stomach cramps, and vomiting, to name just a few. Remember a lower micron level is better when it comes to cleaner and healthier drinking water. 


So why does it matter to filter down to the smallest micron? Ultimately, low micron levels determine how well a carbon filtration water filter will function. Most likely, if a filter only removes so much chlorine or so much lead, it is probably because of the micron level. The price of a good water filter with a low micron level will be a little bit more expensive than a filter with a higher micron level, but it’s worth it. A low micron-level filter will even get the hard stuff that is typically impossible to eliminate, like excessive fluoride from your water 

Our biggest advancement yet, the OptimH2O Whole House Filter, is a first-of-its-kind system that filters down to 0.5 microns to reduce lead, cysts, PFOA/PFOS, chlorine, chloramines and much more. Designed with a giant, ultra-dense carbon block, this system is engineered to offer superior filtration compared to granular media. It also uses catalytic and activated carbon, combined to perform ion-exchange and sub-micron filtration for first-of-its-kind effectiveness. 

Shop OptimH2O Whole House Filter


Related to this article

  • How To Choose A Drinking Water Filter

    Drinking water filters have a lot of components. Read this comparison list when deciding which one is right for you. Drinking Filters

  • Your Comprehensive Guide to Whole Home Filtration

    Get healthy, great-tasting water from every tap in your home with a whole house water filtration system. Learn more about which whole home solution is right for you. Choosing Whole Home

  • Reverse Osmosis Explained

    Reverse osmosis offers to provide the "cleanest" water available. Are there any down sides to the RO process? Reverse Osmosis 101

More Products

To give you the best possible experience, our website uses cookies. You can review our privacy policy to find out more about the cookies we use and how to adjust your browser settings to block cookies. If you close this box or continue browsing our website, you accept our use of cookies.