How Often to Change a Water Filter: What to Look For

Water Filter Attached to a Faucet - How Often to Change Filter Article

Water filtration is great. It provides a solution to just about any mineral or even chemical and bacteria that might be lurking in your home’s drinking water. Unfortunately, filters are far from a “fix it and forget it” solution. They need to be maintained according to the recommendation of the manufacturing company in order to ensure the life of the filtration system and ultimately, the quality of the water in your home.

How Often to Change a Water Filter

So, how often should you change a water filter? There is an easy and less straightforward answer.

The simple answer is about every two months. Over the course of a couple of months most filters will filter 40 gallons of drinking water which is also a good number to keep in mind.

  • Based on time: About 2 months
  • Based on volume (pitchers): About 40 gallons
  • Based on volume (faucet mount or reverse osmosis): About 100 gallons

That said, there are some things that might change the answer for your specific situation such as:

  • What is being filtered
  • Level of contaminants in the water
  • How much use your filter gets
  • Kind of filter you have


Part of the reason there isn’t always an easy answer to this question is because different water contains different amounts of contaminants. If you have particularly hard water or know you are filtering out high levels of contamination (sediment, chemical, or biological), you may need to change the filter more often then the conventional two months.

Depending on the kind of filter you have, some of the minerals in your water may be pretty hard on the filter itself.

Think of a fine mesh sieve as an example; if you are straining something through the sieve, the bigger the particle the sooner the sieve will become blocked and need to be cleaned (or replaced).


Even if you don’t have hard water, or a whole bunch of contaminants you are treating, you still may need to change a filter more often than every couple months if there are lots of people using the system.

Water Filter Banner Photo

One person living alone and using a filtration system to treat their drinking water can probably wait longer  than a family of 6 using the filter. Even a couple of people filtering all the water they use instead of just drinking water may not get as long out of a filter as a family filtering drinking water only.

In my experience it can be easy to install a water filtration system and get lulled into a false sense of clean water security by the idea of the filter working indefinitely.

To add a level of mystery to the topic: Dirty or unhealthy water can look and even taste fine. How in the world are you supposed to know when to replace that filter?

Understanding the type of filter can help you out.

Timing of Replacement based on Filter Type

Obviously there are lots of varieties of filters from pitchers to systems inside a refrigerator.

The good news is that often there are instructions that come with your water filter or even a handy indicator to tell you how the filter is functioning and give you notice of when it will need to be replaced. If not, fall back on the 40 gallons for pitchers and 100 gallons for faucet mounted filters rule based on the numbers we listed earlier.

For larger systems installed throughout the whole house, check with the manufacturer for specific instructions on the lifespan of your filter. Pitchers and jugs often come with little calendars to remind you which can be very helpful. If all else fails, err on the side of caution especially if you are particularly concerned about what is in your water.

A conservative approach would be to change the filter between 2 and 6 weeks for those who need to be extra careful.


So, to recap: changing a water filter is crucial to the function of the filtration system, but a straightforward solution can be hard to determine. I highly recommend researching your specific system as well as the kind of water you are putting through it to determine a tailored approach to keeping your filter functioning well. Keep in mind the factors mentioned above as well as the general rules or 2 months/40 gallons for many filtration systems.

Leave a Reply

Your email address will not be published. Required fields are marked *

Click outside to hide the compare bar
Compare ×
Let's Compare! Continue shopping