Which is better 5 micron or 20-micron

Spend enough time researching and comparing water filters, and you’ll come across the oft-advertised micron. But what exactly is a micron, and what does it mean for your water filter?

We’ve collected a selection of the most frequently asked questions about water filter micron size. We’ll translate the answers into plain English to help make you better informed about your next water filter purchase.

What is a micron filter?

A micron filter, then, is any type of filter that can remove contaminants down to a certain micron size. They’re useful in removing common materials like dirt and debris. But they really shine in their ability to remove things other filter media might miss, like bacteria and cysts.

How big is a micron?

Micron is the common name for a unit of measure also known as the micrometer (μm). It’s equivalent to 1 one-millionth of a meter, making a single micron invisible to the naked eye.

To put that in perspective, human hairs measure on average 20 to 200 μm. The micron is also used to measure bacteria, which range from 1 to 10 μm. Take note of this, as it will be important later.

Impact on Water Pressure

There’s an inverse relationship between how fine a micron filter is, and how much it might affect your water pressure.

Think of it this way: If you try to pour a glass of water through a funnel with a tiny opening, it will take quite a while. But if you increase the size of the funnel’s opening, it pours faster.

The same is true of micron size for filters. The smaller the micron size, the longer it takes for water to pass through it. So while smaller micron filters will remove more contaminants, they are also more likely to decrease your flow rate and water pressure.

So ideally, you’ll get a micron filter that is appropriate to the contaminants in your water. If your water is relatively clean and pure, a micron filter may not even be necessary. But if your water is heavily compromised, the smaller the micron filter the better (at least 5 microns, though 1 or .5 microns is better).

Nominal vs. Absolute Micron Rating

You’ll find two types of micron ratings: Absolute and nominal.

Nominal micron ratings show the approximate size of particles that the filter can remove.

Absolute micron ratings guarantee that the filter will remove 99.9% of the particles that are larger than the given micron size.

So nominal ratings are approximate, and absolute ratings are guaranteed. In effect, absolute ratings are more reliable.

Popular Micron Ratings

Water filters come in a wide range of micron ratings. The smallest micron filters will be found at .5 microns. From there, you’ll also find filters with 1 and 5-micron ratings. After this, the numbers start to jump more quickly to 10, 25, 50, 75, and 100 microns.

How Many Microns Do You Need?

With all of the above questions in mind, how can you find the best micron filter for your needs? You’ll need to start with a Consumer Confidence Report. It’s a readout of your water quality that’s specific from location to location. The EPA provides a tool for finding and requesting your CCR at this link.

Once you know what contaminants are in your water, you can compare their micron size to this chart. Then it’s as easy as identifying the smallest micron contaminant and getting a filter that has a micron rating equal to or lower than that.

Frequently Asked Questions

What is micron rating?

The micron rating for a given filter represents how fine its filter media is. This relates directly to the micron size discussed above. It matters because the micron size will determine what the filter removes from your water, and what it lets stay in.

Are there any disadvantages to using a micron filter?

Smaller micron filters may reduce your water pressure. That’s because the water has to pass through smaller areas, reducing its speed and flow rate. Additionally, the smaller end of micron filters can be prone to clogging from larger particles. In short, there’s no one size fits all solution to micron water filters.

The contaminants that are removed will depend on the size of the filter, which can range from 0.0001 to 800 microns.

The higher the micron rating, the bigger the particles it can trap.

Table of Contents

What is Micron Filter Rating?

The size of the perforations in the mesh determines the micron filter rating.

This can range from 0.0001 to 800 microns, comprising materials (1)such as nylon, polyester, and polypropylene.

To put this is perspective, here are a few examples of particle or micron filter size of day-to-day materials:

Carbon dioxide0.00065 micronsBacteria0.3 – 60 micronsTobacco smoke.01 – 4 micronsFine silt 4 – 8 micronsHuman hair40-300 microns

The molecule size of any material will determine whether or not it can pass through a micron filter. If the molecules are bigger than the holes in the mesh, they will be unable to percolate through and will remain in the water or air.

The human eye can see objects that are greater than 40 microns, such as dust mites.

What is the Difference Between Micron and Mesh Filters?

Mesh Filter
Micron Filter

Micron filters comprise various porous materials which have a specific gap size between the fibers.

Mesh filters comprise wire mesh which is measured by a number of strands or threads per linear inch.

You cannot correlate directly between mesh size and microns as the diameter of the wire itself will differ according to its manufacture.

The size of the aperture cannot be used as a micron measurement, as the greater, the number of wire strands present, the smaller the gaps between them will be, reducing the micron size.

Understanding Micron Ratings

One micron measures 1/25400 of an inch, or one inch contains 25,400 microns.

Thus, the greater the micron rating, the greater the size of the particles that can be filtered.

Here is a comparison of different micron sizes:

ParticleParticle Size
(microns)Anthrax1 – 5Antiperspirant6 – 10Asbestos0.7 – 90Atmospheric Dust0.001 – 40Auto and Car Emission1 – 150Bacteria0.3 – 60Beach Sand100 – 10000Bone Dust3 – 300Bromine0.1 – 0.7Burning Wood0.2 – 3Calcium Zinc Dust0.7 – 20Carbon Black Dust0.2 – 10Carbon Dioxide0.00065Cayenne Pepper15 – 1000Cement Dust3 – 100Clay, coarse2 – 4Clay, medium1 – 2Clay, fine0.5 – 1Coal Dust1 – 100Coal Flue Gas0.08 – 0.2Coffee5 – 400Combustion0.01 – 0.1Combustion-related – motor vehicles, wood burning,
open burning, industrial processesup to 2.5Copier Toner0.5 – 15Corn Starch0.1 – 10Dot (.)615Dust Mites100 – 300Eye of a Needle1230Face Powder0.1 – 30Fertilizer10 – 1000Fiberglass Insulation1 – 1000Fly Ash1 – 1000Gelatin5 – 90Ginger25 – 40Glass Wool1000Grain Dusts5 – 1000Gravel, very fine (0.08 inch)2000Gravel, fine (0.16 inch)4000Gravel, medium (0.3 inch)8000Gravel, coarse (0.6 – 1.3 inches)15000 – 30000Gravel, very coarse (1.3 – 2.5 inches)30000 – 65000Ground Limestone10 – 1000Hair5 – 200Household dust0.05 – 100Human Hair40 – 300Human Sneeze10 – 100Humidifier0.9 – 3Insecticide Dusts0.5 – 10Iron Dust4 – 20Lead, solder radiator manufacturing – mean value1.3Lead, battery and lead powder manufacturing12 – 22Lead Dust0.1 – 0.7Liquid Droplets0.5 – 5Metallurgical Dust0.1 – 1000Metallurgical Fumes0.1 – 1000Milled Flour, Milled Corn1 – 100Mist70 – 350Mold3 – 12Mold Spores10 – 30Mustard6 – 10Oil Smoke0.03 – 1One inch25400Oxygen0.0005Paint Pigments0.1 – 5Pesticides & Herbicides0.001Pet Dander0.5 – 100Pollen10 – 1000Radioactive Fallout0.1 – 10Red Blood Cells5 – 10Rosin Smoke0.01 – 1Sand, very fine (0.0025 inch)62Sand, fine (0.005 inch)125Sand, medium (0.01 inch)250Sand, coarse (0.02 inch)500Sand, very coarse (0.02 inch)500Saw Dust30 – 600Sea Salt0.035 – 0.5Silt, coarse (0.0015)37Silt, medium (0.0006 – 0.0012 inche)16 – 30Silt, fine 8 – 13Silt, very fine4 – 8Skin flakes0.5 – 10Smoke from Natural Materials0.01 – 0.1Smoke from Synthetic Materials1 – 50Smoldering or Flaming Cooking Oil0.03 – 0.9Spanish Moss Pollen150 – 750Spider web2 – 3Spores from plants3 – 100Starches3 – 100Sugars0.0008 – 0.005Talcum Dust0.5 – 50Tea Dust8 – 300Textile Dust6 – 20Textile Fibers10 – 1000Tobacco Smoke0.01 – 4Typical Atmospheric Dust0.001 to 30Viruses0.005 – 0.3Yeast Cells1 – 50Micron Filter Size Chart

5 micron

This will filter out some bacteria, including anthrax, some molds, coffee granules, and paint pigments.

10 micron

This will filter out red blood cells, carbon dust, fertilizers, and insecticides.

Recommended Reading: Best Whole House Water Filters – Reviews + [Guide 2021]

25 micron

This will filter out white blood cells, salt, sand and rust particles.

30 micron

This will filter out algae, solvents, silt and milled flour.

50 micron

This will filter out coal dust, pet dander, human hair, and plant spores.

Which Micron Filter Size is Best for Me?

Before you decide on which filter and which micron is best suited to your needs, you need to know what contaminants or other materials are in your water.

We know that smaller micron sizes will remove more material, but that may slow down your water flow.

Filters with smaller micron ratings will have to be replaced regularly due to the debris they accumulate.

You may find that it is better to have more than one filter that will progressively remove particles in your water. These would be installed from the coarsest to the finest.

Why Does Micron Size Matter?

The smaller the micron size, the more contaminants are removed during the filtration process.

If you are mainly concerned with removing bacteria, viruses and parasites, a one micron filter will suffice.

If you need to remove sand and silt and other solids, you will need a larger micron size filter, or a series of filters of different micron sizes.

Smaller micron filters may cost more, but will be better for your health in the long term.

What Are Nominal and Absolute Micron Filters?

All filters, regardless of their micron rating, are effective at removing impurities to some degree.

Nominal filters will remove most of the defined pollutants for its particular rating, from about 60% to 98% efficiency levels.

This will vary according to the extent of the pollution and the environment. The capacity of filters may also vary by manufacturer.

Nominal filters will possibly only remove 70% – 80% of the bacteria that cause Cryptosporidium (2), a form of gastroenteritis that will lead to diarrhea and vomiting.

Absolute filters will filter 100% of contaminants at their micron rating. They are tested more exhaustively, including for:

Concentration
Identification
Particle size
Pressure

Absolute filters may be constructed of a solid layer like ceramic, metal or Teflon. The holes are a regular size and are created using a nuclear (3)process.

Absolute filters are used in extreme sterile environments such as NASA.

To ensure that a filter is ‘absolute’, it should include the wording “NSF 53” or “NSF 58” as well as “cyst reduction” or “cyst removal”. Any product that does not feature one or more of these clauses cannot be deemed to be an absolute filter.

What Micron Filter Do I Need for My Well Water?

Filters with micron sizes of between 0.5 – 2 will remove the majority of water contaminants.

You may want to install depth filters, where the micron sizes vary from larger to smaller. The larger holes trap larger toxins and scale down to smaller micron ratings that will catch bacteria and viruses.

Our Recommended Sediment Filter for Well Water in 2021

For water sources with a large surface area, you may consider a pleated filter that can net substances between 30-500 microns. These can also be used for finer filtration of required.

Conclusion

Whatever filtration system you are using, it will be necessary to consider the micron rating of each filter.

The micron ratings used in various categories of filtration include:

Reverse osmosis0.0001 micronNanofiltration .001 micronUltrafiltration.01 micronMicrofiltration0.1 micronParticle filtration0.3 micron

All filters must be inspected and either cleaned or replaced at least once a year, or more often if you deem it necessary.

Is higher or lower micron better?

When filtering solids from liquids, the smaller the micron rating, the more effective the filter and the greater the number of particles that are removed from the final filtrate.

What is finer 5 micron or 10 micron?

The smaller the micron rating, the finer the particulate removed. Which size micron filter you need depends on the size of the smallest particle that needs filtering from your water. A 5-micron filter, for example, removes particles as small as 5 microns. Anything smaller passes through the pores.

What is bigger 5 micron or 50 micron?

The micron rating refers to the distance between pieces of filter media. This determines the size of particles that the filter will allow to pass through. A 50 micron rated filter will allow larger particles to pass through than say a 5 micron rated filter.

Is a 5 micron filter better than a 10 micron filter?

This rating filters a little less than the 5 micron rating. Filters with a 10 micron rating can remove some unseen materials from liquid but not bacteria or viruses. However, 10 micron is still very small and can benefit many industries, from oil to chemical plants, because of their ability to filter so much.