The box says six months. Your water says otherwise.
Enter your zip code for a replacement schedule based on how hard the water actually is where you live.
Replace your filter every months
Your filter is about overdue
- Next replacement
- Water hardness
- Classified as
- Data source
Grains per gallonThis measures how many minerals are in your water. Higher means harder water and a faster-clogging filter.
Estimate based on regional water-hardness data — not a reading from your utility.
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How the estimate works
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Step 1
We find your area. You type your zip code. We use it to look up your county.
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Step 2
We check how hard your water is. Hard water has extra minerals in it. Those minerals build up inside your filter and clog it. We look up a hardness number for your county. The higher the number, the harder your water, and the faster your filter fills up.
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Step 3
We tell you when to change it. A fridge filter can handle a set amount of water before it stops working. Hard water uses that up faster. Soft water makes it last longer. We start with the standard six months printed on the box and move it earlier or later based on your water. Tell us how many people are in your home and we adjust for that too.
Common questions
How often should I really replace my refrigerator water filter?
The box says six months, but that's a guess that ignores where you live. Hard water clogs a filter faster. Soft water lets it last longer. Most people in hard water areas should change it every four to five months. Soft water areas can stretch to seven. Enter your zip and we'll give you a number based on your actual water.
What is hard water and why does it matter for my filter?
Hard water has extra minerals dissolved in it — mainly calcium and magnesium — picked up as water moves through rock underground. Those minerals build up inside your filter over time and clog it. The harder your water, the faster that happens, and the sooner you need a new filter.
What happens if I don't change my filter?
A clogged filter stops removing contaminants and slows your water flow. You end up drinking water that's going through a blocked filter — which is worse than no filter at all in some cases. Changing on schedule keeps your water clean and your fridge's water system working properly.
Does hard water affect anything else in my home?
Yes. The same minerals that clog your fridge filter also build up in your pipes, water heater, dishwasher, and shower head. You'll see it as white scale on faucets and spots on glasses. Hard water makes soap less effective too — you need more of it to lather. A fridge filter won't fix those problems, but it does protect the one appliance most people forget about.
Do I need my fridge brand's official filter, or will a compatible one work?
Compatible filters from other brands work fine for most people and cost less. Look for ones that are NSF/ANSI 42 or 53 certified — that's the standard that confirms they actually filter what they claim. The Amazon links on this site show both official and compatible options for your fridge brand.
Is this the same as a water quality or safety report?
No. We only estimate water hardness and tell you when to change your filter. We say nothing about whether your water is safe to drink — that's a different question. For contaminant and safety data, read your utility's annual water quality report, which is mailed to customers every year and available on your utility's website.