Replace the charcoal water filter in your coffee maker every 60 days or after 60 uses, whichever comes first. Change it sooner if your tap water is heavily chlorinated or your coffee starts to taste flat or off. The filter takes out chlorine, odors and other impurities that change how coffee tastes, and a spent one stops doing that.
Updated October 2026. This answer first ran in our FAQ. We've added how to tell a filter is spent, how to put in a new one, and why you still need to descale.
Fresh brewed coffee is about 98% water, so your water matters as much as your beans. The small charcoal filter that sits in many coffee makers' water reservoirs is there to strip out chlorine, odors and impurities before the water reaches your grounds.
How often to change it
Every 60 days or 60 uses is the standard for coffee maker charcoal filters, and the box for your filter will give its own rating. Treat that as a ceiling, not a target. If your water is heavily chlorinated, or you brew several pots a day, the charcoal fills up sooner. Many filter holders have a date dial, so set it to the month you put the new filter in and you won't have to remember.
Signs your filter is spent
- Your coffee tastes flat, bitter or a little like a swimming pool, with the same beans and grind as before.
- The water itself smells of chlorine as it fills the reservoir.
- The date on the holder, or your machine's filter reminder, says it's been two months.
How to put in a new filter
Check the instructions on the filter's package, since soak times vary by brand. Most coffee maker filters get a short soak in cold water to push out trapped air and loose carbon dust, then a rinse under the tap. Fit the filter into its holder, put the holder back in the reservoir, and set the date dial if there is one. Run one reservoir of plain water through the machine and pour it out before you brew.
Black specks in your first cup after a change are loose carbon dust from a filter that wasn't soaked and rinsed. They're harmless, but annoying. Run another reservoir of water through and they'll clear.
A charcoal filter doesn't replace descaling
Activated charcoal is good at taste and smell. It does much less against the calcium and magnesium in hard water that turn into scale, so even with a fresh filter your coffee maker still builds scale and still needs descaling on its own schedule. Our guide on how to descale a coffee maker covers Keurig, Nespresso, De'Longhi and most drip machines, and our descaling guide by appliance covers everything else.
What about pitcher and refrigerator filters?
They run on their own ratings, usually a number of gallons or months printed on the filter or in the manual. Follow that rating rather than the 60-day coffee maker rule.
Frequently asked questions
What happens if I don't change my coffee maker's charcoal filter?
The charcoal fills up and stops filtering, so chlorine and odors go straight into your coffee. Very old filters can also pick up stale tastes of their own.
Do I need a charcoal water filter in my coffee maker?
No. The machine works without one. The filter is there to improve taste, and it matters most if your tap water tastes or smells of chlorine.
Does a charcoal filter mean I don't have to descale?
No. Charcoal does little against the minerals that form scale, so keep descaling on your machine's schedule.