Yes, within a narrow job. A refrigerator cartridge is a compact carbon block sized for the water going to one dispenser and ice maker, so it takes out chlorine taste, odor and grit, and depending on its certification a short list of other reductions. It does nothing about hardness, and it is not a purifier for a supply you have reason to distrust.
What the cartridge is actually doing
Water is pushed through compressed carbon at low flow. Carbon adsorbs chlorine and the organic compounds behind musty, plastic or swampy tastes, and the block itself strains fine particles. That is why filtered fridge water tastes cleaner and ice comes out clear instead of cloudy. The effect is real and immediate, and it is the reason most households notice the difference the day the cartridge is changed.
What it will not do, no matter which brand you buy
Carbon does not remove dissolved calcium and magnesium, so filtered fridge water still leaves scale in a kettle and still spots glassware. It is not a disinfection device, so it is the wrong answer to a positive bacteria result. Anything beyond taste and chlorine reduction, including lead or emerging contaminants, is only true if that exact reduction is printed on the cartridge as a tested claim. Treat an unlabeled claim as absent.
How you know it has stopped working
Carbon exhausts quietly. There is no alarm and no visible change, which is why the indicator light on the door is a calendar timer and not a measurement of the media. The honest signals are a chlorine taste returning, ice that smells of the freezer again, or a noticeable drop in dispenser flow, which usually means sediment has blinded the face of the block. Once carbon is loaded, contaminants it once held can be pushed through by fresh water.
Choosing a replacement without wasting money
Buy on two things: physical fit for your fridge model, and the reduction claims printed on the box. A cheap universal inline cartridge fitted to the supply line behind the fridge does the same taste job as a costly proprietary one, but it may carry fewer tested claims. If the whole house needs help rather than one dispenser, a fridge cartridge is the wrong tool and the money belongs in a point of entry or under sink system instead.
Questions people ask about do refrigerator water filters work
Does a refrigerator filter soften water?
No. Carbon does not remove calcium and magnesium, so the filtered water is exactly as hard as the water entering the fridge.
Can an old cartridge make water worse?
It can. An exhausted block traps sediment and can shed accumulated taste back into the water, and slow flow at the dispenser is the usual first clue.
Is it safe to run the fridge on bypass?
The appliance runs fine on a bypass plug, but you get unfiltered water and ice. It is a stopgap while you wait for a cartridge, not a plan.
Should I filter at the fridge or under the sink?
Under the sink treats the drinking tap and can be a larger, longer lived cartridge. The fridge filter only ever treats the dispenser and ice maker.