Micron rating is an important factor to the effectiveness and filtration performance of a filter cartridge or a filter bag. If you want to get a perfect filtration result, it is essential to select the right micron rating for your operation condition.
If you want to know more about microns, or choose a proper filter cartridges based on needed micron ratings, feel free to contact us.
What Micron Rating Do You Need for Well Water?
Well water carries a different mix of contaminants than municipal water, typically higher levels of sediment, sand, rust, and sometimes bacteria or iron depending on your geology and well depth. A single micron rating rarely covers everything, which is why well water systems almost always use two filtration stages.
Recommended well water filtration sequence:
Stage 1 – Coarse pre-filter: 20–50 micron
This removes sand, silt, and large sediment particles that would rapidly clog a finer filter. Use a 20 micron pleated or 50 micron bag filter here.
Stage 2 – Fine filter: 1–5 micron
This removes finer sediment, rust particles, and fine silt before the water reaches your tap or appliances. A 5 micron depth cartridge is the most common choice for well water.
If bacteria or cysts are a concern in your well water, add a 0.5 micron absolute-rated filter or a UV disinfection stage after the sediment filters. A 5 or 10 micron sediment filter alone does not remove bacteria.
For most residential well water systems with moderate sediment: a 20 micron pre-filter followed by a 5 micron polishing filter is the standard starting point.
Related Question About Microns in Water Filter
Here are the questions people mostly asked:
Is a lower or higher micron rating better?
It depends on what you need to remove. A lower micron number means the filter captures smaller particles, a 1 micron filter is finer than a 10 micron filter. Lower is not always better though. A 0.2 micron filter clogs far faster than a 5 micron filter when the water carries a heavy sediment load. For most applications, match the micron rating to the particle size you need to remove rather than always choosing the lowest available.
Which is better, 5 micron or 20 micron?
A 5 micron filter removes finer particles but clogs faster. A 20 micron filter flows more freely and lasts longer but passes particles that a 5 micron would catch. For most residential whole house systems, a 20 micron pre-filter protecting a 5 micron fine filter downstream gives you the best of both, coarse particles are removed first so the fine filter lasts significantly longer.
What does a 5 micron water filter remove?
A 5 micron filter removes sediment, rust, sand, silt, and fine particulates down to 5 micrometres in size. It does not reliably remove bacteria, viruses, or dissolved contaminants such as chlorine, heavy metals, or salts. For bacteria removal you need a 0.2 or 0.5 micron absolute-rated filter, and for dissolved contaminants you need an activated carbon or reverse osmosis stage.
What does a 1 micron water filter remove?
A 1 micron filter removes fine sediment, rust, and parasitic cysts such as Cryptosporidium and Giardia, which are typically 3–10 microns in size. At 1 micron you are approaching the size needed to physically block some bacteria, but for reliable bacteria removal a 0.2 micron absolute-rated membrane filter is the correct specification.
Will a 5 micron filter remove bacteria?
Not reliably. Most bacteria range from 0.2 to 2 microns in size, which means a nominally rated 5 micron filter does not block them consistently. For effective bacteria removal you need either a 0.2 micron absolute-rated membrane filter or a UV disinfection stage. A 5 micron sediment filter is a pre-filter, it protects downstream equipment but is not a disinfection method.
What micron filter is best for drinking water?
For municipal tap water, a 5 micron sediment filter followed by an activated carbon stage handles most drinking water concerns, sediment, chlorine taste, and odour. For well water or water with biological risk, add a 0.5 micron absolute filter or UV disinfection stage. If you want the highest purity, a reverse osmosis system with a 0.0001 micron membrane removes dissolved salts, heavy metals, and most contaminants.
What micron filter is best for well water?
A two-stage approach works best for most well water: a 20–50 micron pre-filter to capture coarse sediment and protect the second stage, followed by a 1–5 micron fine filter for polishing. If your well water tests positive for bacteria or cysts, add a 0.5 micron absolute filter or UV stage after the sediment filters. Get your well water tested first, the results tell you exactly what you need to remove.
What micron rating do I need for a whole house water filter?
For city water with normal sediment levels, a single 5–10 micron whole house cartridge is sufficient. For well water or homes with older iron pipes, use a 20–50 micron coarse filter as the first stage and a 1–5 micron filter as the second stage. Running a 1 micron filter directly on unfiltered well water without a coarse pre-filter will clog the fine filter within days.
What micron size does a reverse osmosis system use?
RO membranes operate at approximately 0.0001 microns, small enough to reject dissolved salts, heavy metals, bacteria, and viruses. However, RO membranes are sensitive to suspended solids and require pre-filtration. Most RO systems use a 5 micron sediment pre-filter to protect the membrane from fouling and extend its service life.
Is a 10 micron filter good for water treatment?
A 10 micron filter is good for removing sand, silt, rust, and coarse sediment. It is widely used as a whole house pre-filter and as a first-stage pre-filter before reverse osmosis systems. It does not remove bacteria, viruses, or dissolved contaminants. For most households on city water with visible sediment or rust issues, 10 micron provides effective protection without the rapid clogging risk of finer ratings.
