Bacteria and parasites
Outside what a normal filter jug does, and one jug is built specifically to do it.
Most filter jugs cannot do thisA carbon cartridge is not a microbiological barrier. Worse, a damp carbon bed at room temperature is a rather good place for bacteria to grow, which is the real reason manufacturers insist on replacing cartridges on schedule and refrigerating filtered water. On a treated mains supply this is not a problem worth solving, because chlorine already solved it. On a private well, a rainwater supply, or travel to somewhere the supply is not reliably treated, it is the whole problem — and only a membrane jug addresses it.
How you know you have it
- A private well, borehole or spring supply rather than treated mains
- A boil-water notice
- Travel to a country where the tap supply is not reliably potable
What works
LifeStraw Home, whose hollow-fibre membrane is tested to the NSF P231 microbiological protocol. That is the only mainstream jug that makes this claim.
What does not
Every carbon and ion exchange jug — Brita, PUR, ZeroWater, Philips, BWT and all the rest.
Cartridges that reduce bacteria
Ordered by strength of evidence, not by brand. An independently certified claim outranks a lab-tested one, which outranks a manufacturer’s word for it.
Cartridges that do not
These make no claim here, and that is not a criticism — it is what their manufacturers say. Buying one of these for this problem is the mistake.
Questions
Does a filter jug remove bacteria?
Very few do. LifeStraw Home, whose hollow-fibre membrane is tested to the NSF P231 microbiological protocol. That is the only mainstream jug that makes this claim.
What does not work: Every carbon and ion exchange jug — Brita, PUR, ZeroWater, Philips, BWT and all the rest.