By Marcus · Updated May 2026
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Your coffee maker has a little charcoal filter tucked inside the water reservoir, and if you haven’t swapped it in the last sixty days, your morning cup tastes like whatever’s in your tap water — chlorine, minerals, maybe a hint of metal. Most brands recommend replacing it every two months or after sixty brew cycles, whichever comes first. Skip it and you’re not getting sick, but you’re definitely not tasting the coffee you paid for.
Cuisinart, Mr. Coffee, and KitchenAid all use similar charcoal filters, but they’re not universal. Each brand has its own size and holder design. The good news: they’re cheap, easy to find online, and take about three minutes to install once you know where to look.
What you’ll need
- Replacement charcoal filter (brand-specific — check your model number)
- Cold tap water
- Small bowl or mug
- Paper towel
- Your coffee maker’s manual (or a flashlight to peek inside the reservoir)
Step 1: Find the filter holder
Open your water reservoir and look for a small plastic cage or slot — it’s usually in the back corner or along the side wall. Cuisinart models have a blue or gray holder that twists out. Mr. Coffee and KitchenAid versions typically slide or snap out from a track.
Step 2: Remove the old filter
Pull the holder out and pop open the cage. The old filter will be discolored — gray or brown instead of black. Toss it. Rinse the holder under tap water to clear out any grit.
Step 3: Soak the new filter
Drop your new charcoal filter into a mug of cold water and let it sit for five minutes. This flushes out loose carbon dust and primes the charcoal so it starts filtering right away.
Step 4: Insert the new filter
Shake off excess water, slide the filter into the holder, and snap or twist the cage shut. Some Cuisinart models have a date wheel on the holder — set it to two months from now so you remember when to replace it again.
Step 5: Reinstall and run water through
Push the holder back into its slot in the reservoir until it clicks or seats firmly. Fill the reservoir and run a full brew cycle with no coffee grounds. This rinses any remaining carbon dust out of the system.
Pro tips & common mistakes
If your machine doesn’t have a date reminder, stick a note in your phone for sixty days out or write the replacement date on the filter holder with a Sharpie. The biggest mistake is forgetting to soak the new filter — if you skip it, your first couple of pots will have black specks floating in the carafe. Also, some Mr. Coffee models ship with a filter holder that isn’t installed at all. Check the box or the manual insert if you can’t find it inside the reservoir.
Generic filters work fine if they match the dimensions, but double-check reviews. I’ve seen off-brand versions that shed carbon like a shedding dog. If your machine is older than five years and the holder is cracked, most brands sell replacements for under ten bucks.
Related guides
- Review of the Braun Brewsense 12-Cup Drip Coffee Maker
- Coffee Maker under $200 Buyer’s Guide 2026: Top 7 Picks
- How to Descale a Cuisinart Coffee Maker
- How to Replace a Keurig Water Filter
Frequently asked questions
Can I use my coffee maker without a water filter?
Yes. The machine will brew just fine. You’ll taste your tap water more clearly, and mineral buildup inside the machine may happen faster, but it won’t break anything. If you use filtered or bottled water already, skipping the charcoal filter is totally reasonable.
Are charcoal filters universal across brands?
No. Cuisinart, Mr. Coffee, and KitchenAid filters are different sizes and shapes. Always check your model number and buy the brand-specific filter. Using the wrong one means it won’t fit in the holder or won’t seal properly.
How do I know when it’s time to replace the filter?
Most brands say every two months or sixty brew cycles. If you brew daily, that’s about eight weeks. If your coffee starts tasting flat, metallic, or like tap water, the filter is probably spent even if it hasn’t been two months.
Do I need to descale my coffee maker if I use a filter?
Yes. The charcoal filter removes chlorine and some impurities, but it doesn’t stop mineral scale from hard water. You still need to descale with vinegar or a descaling solution every three to six months depending on your water hardness.
What if my coffee maker didn’t come with a filter?
Many budget models don’t include a filter holder at all. Check your manual or the manufacturer’s website — sometimes it’s an optional accessory you can buy separately. If your model doesn’t support one, just use good water and descale more often.