A household jug filter is the cheapest meaningful improvement to brewing water.
What it does
Removes chlorine via activated carbon. This alone transforms water that tastes of the pool.
Reduces hardness and alkalinity by ion exchange, typically by 30 to 60% depending on the cartridge and how fresh it is.
Removes some metals and organics.
What it does not do
Produce a consistent output. A fresh cartridge removes far more than one near the end of its life, so your water changes over the month.
Give you a target profile. It reduces what is there; it cannot add what is missing.
Over-soften. In very soft-water regions, a jug filter can leave the water too low in minerals, giving hollow coffee. Rare, and it happens.
Is it enough
For most people, yes. It handles chlorine and excess hardness, which are the two big problems in ordinary tap water.
For a coffee machine, yes — it substantially slows scale.
For competition-level filter brewing, no — that is what recipe water is for.
Getting the most from it
Change the cartridge on schedule. An exhausted cartridge does nothing and can harbour bacteria.
Rinse new cartridges as instructed — the first litre carries carbon dust.
Keep the jug in the fridge and use it within a couple of days. Filtered water has no chlorine and therefore no biological protection.
The upgrade path
Jug filter, then bottled with a known profile, then recipe water.
Last reviewed 8 August 2026