How Often to Replace a Brita Filter? Every 4 Weeks

Reading time: ~10 minutes

1. How often should you replace a Brita filter, by type?

In its own FAQ, Brita applies one main rule: the filter cartridge in a water filter jug comes out at least once every 4 weeks. The manufacturer also states a capacity in litres, and in practice that figure matters more than the calendar. If you filter very little, you will reach the 4 weeks comfortably. If you fill the jug three times a day, you will run through the capacity before you run through the month.

That bottom row is not there by accident. The difference in replacement frequency between a filter jug and an inline system under the worktop is a factor of thirteen, and that difference is the heart of this whole subject. If you first want to understand which technologies exist and what they do and do not remove from your water, our overview of the different types of water filter sets it out.

2. Why four weeks, and does a filter really last that short a time?

This is the question that comes up most often on forums: are those four weeks a technical limit or a business model? The honest answer is that two different clocks are running, and both of them count.

Clock one: the capacity in litres

Activated carbon works by adsorption. Substances attach themselves to the vast internal surface area of the carbon granules, and that surface area is finite. That is exactly why the NSF/ANSI standards 42 and 53 are built around a tested capacity: a reduction claim only holds within the number of litres the system was tested for. With a cartridge rated at around 150 litres, that limit is therefore in sight within a month if your household drinks and cooks with a few litres a day.

How quickly that happens also depends on your region. Harder ground means more calcium and magnesium in the water, and that fills up the ion exchange resin faster. In the Netherlands, hardness averages around 8 °dH according to Vitens, which counts as soft to moderately hard water; the law does not allow drinking water companies to soften below 5.6 °dH. If you live in an area with a harder tap supply, you will reach those 150 litres sooner. You can see how hard the water is where you live in our overview of hard water in the Netherlands.

Clock two: the open reservoir

This is the clock most people forget. A filter jug often stands in the fridge or on the worktop with a half-full reservoir, at room temperature, for days on end. A damp, nutrient-rich carbon bed at 20 degrees is a perfectly good habitat for bacteria. That is why the four-week interval is not only a capacity limit but also a hygiene limit. An inline cartridge that is permanently under pressure and fully sealed does not have that second clock, and therefore lasts many times longer.

3. The indicator: how it works and what if the battery is flat?

The lid of most Brita jugs carries an electronic reminder. It does not measure what is in your water; it counts. Depending on the model, it looks at the number of days since the reset, at how many times the lid has moved, or at a combination of the two. As soon as the counter reaches four weeks, the icon or the bar display starts flashing.

That is important to know, because it means two things. First: the reminder is a calendar, not a sensor. If you filter far more than average, you will be through your capacity before the light starts flashing. Second: on virtually every model, the battery in that reminder cannot be replaced. Once it is flat, the indicator stops working, while the jug itself carries on perfectly well. In that case you do exactly what the reminder used to do: put the replacement date in your phone or write it on the cartridge.

Do not forget to reset it either. On most jugs, after fitting a new cartridge you hold the button down for a few seconds until all the bars light up. Skip that step and the reminder will start flashing again within a few days, and you will lose confidence in the system.

4. What happens if you replace it too late?

There are two consequences, and the second weighs heavier than the first.

You stop filtering, without noticing. A saturated cartridge looks identical and the water flows through just as quickly. The taste of chlorine is usually the first thing to return, because that is the function you actually taste. Every other reduction stops without any signal at all.

Water quality can end up worse than with no filter at all. Milieu Centraal states that the quality of your drinking water can actually deteriorate because of a filter, since bacteria can grow on the filter material. Waternet likewise points out that Dutch tap water is already tested daily and that, in their view, a filter at home adds little to that. It is a fair point, and it is exactly why a filter you forget to replace is the worst possible scenario: you get the drawbacks without the benefits.

At PureFilter we see this cited most often by people moving on from a jug. Not the price of the cartridges, but the guilt about the jug that sat on the worktop for three months.

5. Can you clean or reuse a Brita filter?

No. This is the most persistent misconception about filter cartridges, and it is quickly explained. The substances the activated carbon has captured are chemically bound to it. Rinsing, boiling, putting it in the dishwasher or letting it dry does not undo that bond. What you can clean is the jug and the funnel around it, and that is worth doing: rinse them out at least once a week and let them dry.

What people sometimes experience as "it works again" after rinsing a cartridge is flow, not filtration. Water runs through freely again because loose particles have been washed away, but the adsorption capacity has not come back. The same principle applies to all carbon filters; we explain it more broadly in our article on how often you should replace a water filter.

6. How to replace a Brita cartridge in five steps

The job itself takes a few minutes, but two of the steps are often skipped and those are the ones that make the difference.

1. Take the new cartridge out of its packaging and submerge it in cold water for about fifteen minutes so the air can escape. Tap it gently until no more bubbles rise.
2. Rinse the jug and the funnel with cold water and let them drain briefly.
3. Click the cartridge firmly into the funnel until you hear it lock, so no unfiltered water can run past the edge.
4. Discard the first two jugs of filtered water. The first use releases fine carbon particles that can temporarily make the water look greyish. Use that water for your plants.
5. Reset the indicator by holding the button down for a few seconds, and note the date.

Step one and step four are the ones most often skipped. A cartridge that has not been de-aerated lets the water through slowly, which then gets mistaken for a faulty cartridge. And if you do not discard the first jugs, you will taste dust on day one.

7. What does changing twelve times a year cost?

Work the interval through over a full year. Thirteen cartridges a year is not just an expense; it is also thirteen times remembering, thirteen times ordering or fetching, and thirteen fifteen-minute de-aerating sessions. Put the maintenance of an inline system next to that and the picture shifts.

The tap water itself is negligible in this calculation. According to Vewin, the weighted average drinking water tariff in 2026 is 2.05 euros per cubic metre excluding taxes and 2.71 euros including them. That is less than three tenths of a cent per litre. The cost of filtered water therefore sits almost entirely in the cartridges, not in the water. For the PureFilter Mineral+, a single replacement filter costs 65.00 euros for up to 12 months and the twin pack 115.00 euros for up to 24 months, which works out at less than one cent per litre.

If you are considering the step from jug to mains purely because of the hassle, you will find the comparison in our piece on alternatives to Brita filter cartridges. And if someone in your household is still buying crates of water, that calculation is in tap water versus bottled water.

8. Is a Brita filter pointless? An honest answer

No, but it does something different from what many people assume. A filter jug is built to tackle taste, odour, chlorine and limescale. That is the domain of NSF/ANSI 42, the standard for non-health-related contaminants. If your complaint is a smell of chlorine or wisps of limescale in your tea, a jug will serve you well. You can read more about the limescale side in our article on filtering limescale out of your tap water.

The health-related substances fall under NSF/ANSI 53, a separate standard with its own reduction claims for lead, pharmaceutical residues and pesticides, among others. That is a different certification route and a different filter build. Take PFAS: since October 2022 the Netherlands has applied a guideline value of 4.4 nanograms per litre in PFOA equivalents, and the RIVM finds that more than half of the measurements in drinking water sourced from river water come out above it. That same RIVM considers it responsible to carry on drinking tap water, because exposure through drinking water alone stays below the health-based limit value. So if you are basing your filter choice on PFAS, you need to look at exactly what has been tested; our page on the water filter for PFAS sets out which technologies qualify.

The much-asked question "what are the drawbacks of filtered water" has only two real answers in practice: a filter that stays in too long, and a filter that removes the useful minerals along with the contaminants. The second mainly applies to reverse osmosis, which we devoted a separate analysis to in osmosis water and health. Filter jugs from other brands also handle minerals differently; we describe how that plays out with a strongly decalcifying system in our ZeroWater review.

9. Buying advice: change less often, filter out more

If you are sticking with a jug, the advice is simple: buy cartridges several at a time, set a recurring reminder in your phone and rinse the jug out weekly. That way you get everything out of it that is in it.

If it is mainly the rhythm you are struggling with, look at the four points that determine replacement frequency. How many litres does one cartridge cover? How many separate parts do you need to replace? What does a year of filtering cost, not just the purchase? And has the reduction claim been independently tested against NSF/ANSI 42 and 53?

On that last point, the PureFilter Mineral+ is certified to NSF 42, 53, 61 and 372, removes more than 100 contaminants including PFAS, microplastics and heavy metals, and adds calcium, magnesium and potassium back via Swedish Mineral Rock™. The system costs 149.00 euros including the first filter, installation takes 5 to 10 minutes without a plumber or tools, and it comes with a 5 year warranty and 40 days of free returns. After that it is one cartridge a year. If you want to see the options side by side, start with our overview of the best water filter or browse the full range of water filters for the home. Still torn between a jug and a brand alternative? Our Brita water filter review sets out the performance by substance group.

10. Frequently asked questions

11. Conclusion

The question of how often you should replace a Brita filter has a short answer and a long one. Short: every 4 weeks or 150 litres for the jug cartridges and the MicroDisc, around 4 months or 600 litres for the On Tap. Long: two clocks are running, and the hygiene clock of an open reservoir is at least as decisive as the capacity in litres. Cleaning and reusing is not an option, and the indicator on the lid is a calendar, not a sensor.

If you are tired of that rhythm of thirteen changes a year, you will end up at a sealed system under the worktop. The PureFilter Mineral+ brings it back to one cartridge a year at 65.00 euros, is NSF certified to 42, 53, 61 and 372, and adds calcium, magnesium and potassium back after filtering via Swedish Mineral Rock™. Pure water, then, without having to think about it twelve times a year.