5-Micron vs 25-Micron Water Filter – Which to Choose?

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5-micron vs 25-micron water filter – understanding micron ratings is important for choosing a suitable set of (sediment) water filters for your home.

Not all filters are the same, and some do a better job at removing certain contaminants than others.

While there are many parameters to consider, you should start with micron ratings in your planning.

Key Takeaways

  • Test your water to determine if you need a 25 or a 5-micron sediment filter.
  • A 25-micron sediment filter catches large dirt and debris, dust, sand, silt, and asbestos.
  • A 5-micron filter removes all of the above plus certain pathogens and even more dust, silt, and asbestos.
  • Many households can benefit from using a 25-micron filter in at least one step of their overall filtration. Supplementing it with a 5-micron filter can make a lot of sense in some circumstances as well.

About Micron Ratings

A sediment filter’s micron rating identifies the size of contaminants that can be removed by that filter. Anything larger than the filter’s micron rating will be successfully captured by it. Smaller particles on the other hand will still make it through the filter.

How Small Is a Micron?

A micron is equal to 0.000001 of a meter. As such, it’s a pretty small unit of measurement. For comparison: Human hair is usually around 60-70 microns in diameter.

Nominal vs Absolute Micron Ratings

You might notice that some filters are listed with a nominal and some with an absolute micron rating.

The main difference between the two is that the nominal rating is somewhat like an approximation. About 70 to 80% of contaminants of the indicated size will be removed.

An absolute micron rating is the more important indicator, as a filter is guaranteed to remove all contaminants with a size of/above the absolute rating.

sediment water filter cartridges

What’s a Micron-Rated Water Filter?

Simply put, a micron-rated water filter is a filter that’s been tested to verify its contaminant removal capabilities. The manufacturer provides their firm guarantee that the filter will be able to remove contaminants of and above the stated micron rating.

5-Micron vs 25-Micron Water Filter – Choosing the Right Micron Rating

You should always have your water quality tested before choosing the right micron rating. Otherwise, you’re just shooting in the dark and might end up spending a lot of money on something that you don’t actually need.

For example, a 25-micron sediment filter will be ineffective if most of the contaminants you’re dealing with are smaller than that. If you’re mostly dealing with dirt and other larger particles, then a 25-micron filter would make more sense.

What’s more, many homes use step-down filtration. This involves starting with a large filter – for example 100 microns – and adding more filters to the chain, going down in size with each one. You can follow the 100-micron filter with a 25 and lastly a 5-micron step for optimal filtration.

What Do You Want to Remove from Your Water Supply?

Your main consideration for choosing an appropriate sediment filter micron size should be the types of contaminants you’re dealing with. Here are some examples of contaminants that can be removed by a 25-micron filter and a 5-micron filter.

25 Micron

  • Larger dirt such as rust chips
  • Any sand
  • Larger silt
  • Some dust and asbestos

5 Micron

All of the above plus

  • Certain types of bacteria and cysts
  • Even more asbestos and dust
  • Some mold
  • Most silt

micron size chart

Don’t Neglect Water Pressure

You might be wondering why you should even bother with micron ratings instead of just buying the smallest available filter on the market. The reason is that smaller filters come with some inherent downsides: They could limit water flow and cause pressure to drop as they clog up.

Thus, always pay attention to how a specific filter would affect your water pressure. Ideally, you should not go below the size of the smallest contaminants you’ve identified through water testing.

If you have any questions about 5-micron vs 25-micron sediment filters please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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Leave a Comment:

Sharon says May 26, 2023

I am pulling water from a creek with lots of sand which turns to mud. 5micron or 25micron?

    Gene says May 27, 2023

    Hi Sharon,
    If it is sand, 25 microns should be enough.

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