Two cartridges with the same micron rating can behave completely differently, because how a cartridge is built determines where it holds the dirt it catches. Depth constructions hold it through their thickness; surface constructions hold it on their face. That single difference decides how long a cartridge lasts on your water and whether it can be cleaned and reused.
Spun and melt blown: depth, for heavy loads
These are made by spinning fine fibres into a graded structure, coarse on the outside and progressively finer towards the core. Particles are captured throughout the thickness rather than on the surface, which means a large dirt holding capacity and a gradual rather than sudden rise in pressure drop. They are inexpensive, cannot be washed, and are the right choice on well water carrying real sediment, where a surface filter would blind in days.
Pleated: surface area, and washable
A pleated cartridge folds a filter sheet into a concertina, presenting several times the surface area of a plain cylinder in the same housing. On light sediment loads that means good flow and a long life, and many pleated cartridges can be rinsed and reused several times, which suits a household that would rather clean than buy. On heavy loads they blind relatively quickly, because everything collects on the surface, and washing recovers less each time as fine material works into the sheet.
String wound: the traditional depth option
String wound cartridges are yarn wrapped around a core in a pattern that creates a graded depth structure, and they are robust, tolerant of pressure fluctuation and available in a wide range of ratings. They handle heavy sediment well and are often chosen for well water and industrial duty. The trade against melt blown is a slightly less uniform structure, which matters where a tighter rating is being relied on, and some grades shed fibres if run far past their capacity.
Reading the rating, and staging
Whichever construction, check whether the rating is nominal, meaning most particles at that size are caught, or absolute, meaning essentially all are. Only an absolute rating supports a specific claim. And on any supply with a real load, stage the cartridges: a coarse depth cartridge first to take the bulk, a finer one behind it to polish, which makes the fine element last many times longer. Our replacement cartridge guide covers matching elements to the standard housings.
Questions people ask about sediment filter cartridge
Which cartridge type lasts longest on well water?
A depth construction, spun or string wound, because it holds dirt through its thickness rather than blinding on the surface.
Can pleated cartridges be washed and reused?
Many can, several times, which suits light sediment loads. Each wash recovers less as fine material works into the sheet.
Does the same micron rating mean the same performance?
No. Construction decides dirt holding, and the rating may be nominal or absolute, which are quite different claims.
Should I use more than one cartridge?
On any real sediment load, yes. Coarse first then fine makes the fine element last many times longer.