A cartridge fits one housing, and the thread says which

The best water filter cartridges for 2026

A cartridge is a spare part, and the first question is not performance but which housing it fits. Filter bodies are proprietary far more often than they look: makers list the exact models a cartridge drops into, and a cartridge of the same shape from another brand generally does not seal. Where a cartridge screws onto a bottle or a pouch, the fitting is usually a 28 mm threaded neck, and the maker names the standard. Once the fit is settled, read what is published rather than what is implied. The pore rating in microns — hollow-fibre cartridges are commonly stated at 0.1 or 0.2 µm — is a manufacturer figure describing the membrane, and the maker's own instructions state what the cartridge is intended for and what it is not. The rated capacity in litres is the service life the maker claims before replacement, and the flow rate is quoted for a new, clean element. Check the backflush method, since a cartridge that can be cleaned in the field lasts a trip longer. Follow the manufacturer's instructions in all cases. We compare compatible housings, thread standard, stated pore rating, rated capacity in litres, stated flow rate, and backflush method.

The ones worth packing

1. 

   NATURBUMMLER spare element for the 750 ml and 1000 ml filter bottles, 200 litres

   A replacement element sold for two named bottles from the same maker, with a 200 litre rated capacity and nothing published about the membrane behind it.

   Compatible housings

   The maker's own 750 ml and 1000 ml filter bottles — stated as compatible with both

   Thread standard

   Not published on the listing

   Stated pore rating

   Not published on the listing — no micron figure appears in the title or in any of the five bullets

   Rated capacity

   200 litres — stated in the title and repeated in the bullets

   Stated flow rate

   Not published on the listing

   Backflush method

   Not published on the listing — the maker describes changing the element in seconds without tools, which is replacement rather than cleaning

   Amazon reference

   B0C81HV4P1 (same reference on 1 Amazon marketplace)

   EAN

   4262372760067

   • Names the two bottles it belongs to, by capacity, in the first bullet — which is the question a spare element has to answer
   • The 200 litre figure is printed in the title rather than left for the small print
   • No pore rating anywhere, which leaves the column this hub leads with empty

   Best for: Keeping a NATURBUMMLER filter bottle in service without hunting for the model number.

   ≈ 15 €

   Check price on Amazon
2. 

   BACHGOLD two-stage replacement element for the maker's Squeeze filter, 0.2 micron stated

   A two-stage element for the maker's Squeeze filter — and a different housing from the Selfpress bottle reviewed on this site, which is exactly the distinction this hub exists to keep.

   Compatible housings

   The maker's own Squeeze outdoor water filter — stated as the original replacement element for it, developed for an exact fit

   Thread standard

   Not published on the listing

   Stated pore rating

   0.2 micron on the hollow-fibre stage — stated as a 0.2 micron hollow-fibre membrane

   Rated capacity

   Not published on the listing — no litre figure and no service interval appear anywhere

   Stated flow rate

   Not published on the listing — the maker describes manual squeeze operation without quantifying it

   Backflush method

   Not published on the listing — the maker advises pre-filtering heavily sedimented water instead

   Amazon reference

   B0FL8YCP6Z (same reference on 6 Amazon marketplaces)

   EAN

   7649988624858

   • Names both stages rather than calling the element a filter — an electro-adsorptive nanofibre layer and a hollow-fibre membrane, in that order
   • Publishes a pore rating flat at 0.2 micron, with no hedge in front of the number
   • No rated capacity at all, which is the figure that turns a cartridge price into a cost per litre

   Best for: Owners of the maker's Squeeze filter who want the original element rather than a look-alike.

   ≈ $15 / £17 / 20 €

   Check price on Amazon
3. 

   Membrane Solutions C3 bottle cartridge set, one UF element and two ACF elements

   A year of cartridges for one named bottle, publishing a pore rating, two separate capacities and the interval at which each element is meant to be changed.

   Compatible housings

   The maker's own C3 filter bottle — stated in the title and in the first bullet

   Thread standard

   Not published on the listing

   Stated pore rating

   0.1 micron — stated as the filtration accuracy of the combined ACF and UF filter

   Rated capacity

   Up to 500 litres on the ACF element and 4000 litres on the UF element — stated separately, with a recommended change after one year for the UF and after four to six months for the ACF

   Stated flow rate

   Not published on the listing

   Backflush method

   Not published on the listing — the maker publishes replacement intervals in place of a cleaning routine

   Amazon reference

   B0F6LKYPMS (same reference on 6 Amazon marketplaces)

   EAN

   0850071881370

   • Publishes two capacities separately, one per element, instead of one figure for the whole pack — the highest rated capacity of the seven cartridges here at 4000 litres on the UF element
   • States the change interval in months as well as in litres, which is the pair that actually schedules a swap
   • No thread standard, so it is bought by bottle name only

   Best for: Keeping a C3 bottle running for a year in one order, with the change intervals already worked out.

   ≈ $22 / £23 / 23 €

   Check price on Amazon
4. 

   OUTDOOR-FRIENDS EasyPress replacement element, 0.01 micron stated, 2000 litres

   A spare element publishing the finest pore rating and the second-longest capacity on this shelf, sold by a model number that the listing itself gives twice and differently.

   Compatible housings

   The maker's own EasyPress filter bottle — stated; the listing identifies the element by a model number, and the title and the recorded part number give different ones

   Thread standard

   Not published on the listing

   Stated pore rating

   0.01 micron — stated as 0.01 µm in the title

   Rated capacity

   2000 litres — stated in the title as a filter capacity

   Stated flow rate

   Not published on the listing — the maker describes pressing as needing no great force, which is not a figure

   Backflush method

   Not published on the listing

   Amazon reference

   B0D9R1B2FK (same reference on 4 Amazon marketplaces)

   EAN

   4270004275445

   • Publishes a pore rating and a capacity together in the title, which two of the seven cartridges here manage
   • 0.01 micron is the finest figure published on this shelf, and 2000 litres is second only to the 4000 litre element in this hub
   • The bullets describe the bottle — magnetic lid, grip band, handle — rather than the element being sold

   Best for: Replacing the element in an EasyPress bottle, once the model number on your own filter has been read off it.

   ≈ 24 €

   Check price on Amazon
5. 

   GRAYL UltraPress replacement purifier cartridge, 300 cycles

   A press cartridge that names its bottle exactly, publishes its life in cycles as well as litres, and never states the pore size that would let the rest of its claim list be compared.

   Compatible housings

   The maker's own UltraPress purifier and filter bottle of 16.9 fl oz — stated in the first bullet

   Thread standard

   Not published on the listing

   Stated pore rating

   Not published on the listing — the listing describes at length what the cartridge is claimed to handle, and gives no micron figure

   Rated capacity

   300 cycles, quoted by the maker as 40 gal./150 L — stated; unused cartridges are stated to keep for ten years in proper storage

   Stated flow rate

   Not published on the listing

   Backflush method

   Not published on the listing — a shelf life is published instead of a cleaning routine

   Amazon reference

   B09NYLCGTS (same reference on 6 Amazon marketplaces)

   EAN

   0850015512575

   • Names one bottle and gives its size in the same line, which leaves no room for a wrong order
   • Publishes its life two ways — in press cycles and in volume — so it can be compared with cartridges counted either way
   • No pore rating, on the most talkative claim list in this hub

   Best for: Travel with an UltraPress, where a spare cartridge is stored ahead of the trip and replaced as a routine cost.

   ≈ $25 / £30 / 35 €

   Check price on Amazon
6. 

   MSR replacement cartridge for the Guardian pump purifier

   Four bullets, one of which names the pump it belongs to and three of which say nothing — five of the six columns here left blank, and the one that is filled is the one that decides.

   Compatible housings

   The maker's own Guardian pump purifier — stated in the title and in the first bullet

   Thread standard

   Not published on the listing

   Stated pore rating

   Not published on the listing

   Rated capacity

   Not published on the listing — no litre figure, no cycle count and no service interval appear

   Stated flow rate

   Not published on the listing

   Backflush method

   Not published on the listing

   Amazon reference

   B0199BGJ8C (same reference on 6 Amazon marketplaces)

   EAN

   0040818024072

   • Names the pump it belongs to in the title and again in the bullets, which is the one field a spare part cannot leave blank
   • Sold as the maker’s own cartridge for its own purifier, so the fit is the maker’s statement rather than an inference
   • Five of the six columns this hub compares are empty, matched here only by the under-sink cartridge

   Best for: Guardian pump owners buying the maker’s own cartridge, with the specification looked up in the manual rather than on the listing.

   ≈ $180 / £156 / 123 €

   Check price on Amazon

This family belongs to the cooking and water kit — see everything that has to work with it.