How Long Do Water Filters Last? How Often to Change a Water Filter?

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When was the last time you changed the water filter in your home? That’s a question most homeowners are reluctant to answer.

Well, as a rule of thumb, you should change water filters occasionally, depending on their lifespan. Pretty vague, right?

In this article, we discuss the longevity of water filters and how often you need to change them.

Key Takeaways

How long water filters last depends on the filter type, your water usage, and water quality. These are some common types and their filter lives:

  • Under sink water filters – Depending on the model, these could last for 3-12 months.
  • Countertop water filters – Countertop filters have a typical lifespan of about 6 months.
  • Most faucet-mounted water filters need to be replaced every 2 to 3 months.
  • Refrigerator water filters usually need to be changed every 6 months.
  • Shower filters typically last about 6 months.
  • Reverse osmosis systems – An RO membrane last up to 5 years. The other filter elements need replacement much sooner.
  • Pitchers – Pitcher filters only last for about 1 to 4 months.

Why Should I Change My Water Filter?

If you don’t change your whole house water filter, harmful bacteria and other germs and impurities could enter your plumbing system. How?

They find their way through cracks in old or damaged filter cartridges and media.

If you go long periods of time without changing water filters, it’s possible that these contaminants will build up, posing a risk to your health and causing clogs in your sink and shower drains.

A clogged drain can result in flooding, which may damage your furniture or flooring. It can also make it difficult to dispose of waste from your bathroom sinks, tubs, showers, kitchen sink, and washing machine.

Moreover, clogged water filters can reduce water pressure and affect the taste of the filtered water. If a filter hasn’t been changed well past its expiration point, it will no longer be functional, allowing contaminants to seep into your (drinking) water. Thus, and old water filter may be doing more harm than good. By the way, this applies to whole house and point-of-use filters alike.

Factors That Influence How Long a Water Filter Lasts

Here are some factors that determine the longevity of a water filter:

Type of Water Filter

Some water filters last longer than others.

  • For instance, you need to change a sediment pre-filter in a whole house filtration system every few months.
  • Meanwhile, a granular carbon-based post-filter that is part of a reverse osmosis system can last for up to 2 years.
  • Some pitcher water filters are known to last no more than 20 gallons.

Water Usage

The amount of water used either at the point of use or in your entire house also determines how frequently a water filter needs to be changed. How much water you use each day will depend on the size of your family and your household habits.

If your water consumption is high, the filter will have to work more. Thus, it will reach the end of its lifespan sooner. Consequently, if more water is used, the filter needs to be replaced more frequently.

Water Quality

If your water is relatively clean, a filter will last a long time since it doesn’t have to work as hard.

On the other hand, if your household water quality is extremely poor – high in sediments and other impurities – the filter’s functionality will be used up sooner.

In such instances, when you change your water filter, it’s important that you do not leave any residue of the previous filter in place. Doing so will shorten the lifespan of your new cartridge and may cause damage to your home plumbing system.

Different Water Filter Cartridges and Membranes

How Long Does a Water Filter Last?

The lifespan of a water filter is measured either in months or gallons.

Most manufacturers specify the number of gallons of water a filter can purify before it needs to be replaced. Meanwhile, others would say a filter can last for X months or X years.

For instance, if a manufacturer says that Filter XYZ can purify up to 60 gallons before needing replacement and your family uses half a gallon every day, the filter will last for up to four months.

On average, pre-filters last for three to six months; carbon filters can last up to a year, while post-filters need to be replaced every year or two.

Besides, keep in mind that not all elements of a water filter may need replacement at once. For instance, you may need to replace the pre-filters of your countertop reverse osmosis system while the RO membrane is still going strong.

How Often to Change a Whole House Water Filter?

A whole-house water filter should be changed every three to six months on average. However, the filter may last longer if it’s not used as extensively or the water is cleaner.

The replacement frequency for other types of filters are discussed below:

Under Sink Water Filters

Depending on the model, some under sink water filters last for just three months, while others have to be replaced every six to twelve months.

Countertop Systems

Countertop water filters are useful for compact spaces in households with little to moderate water consumption.

These filters typically have a lifespan of or about six months (based on one gallon of purified water per day). If you use more than this amount, it’s advisable to change the filter more often.

Some models may even filter up to 10,000 gallons before needing replacement.

Faucet-Mounted Water Filters

Faucet-Mounted water filters should be replaced every two to three months. Since you use the faucet for filling water bottles and dispensing water for cooking, these filters need replacement more often.

Refrigerator Water Filters

If you use it moderately, replace your refrigerator water filter every six months. It’s also helpful to consult the manufacturer’s guide to learn more about the filter’s lifespan.

Shower Filters

Shower filters last for about six months since they’re not used frequently throughout the day. However, if there’s high chlorine content in your home water, you need to replace the filter more often.

Reverse Osmosis Systems

Reverse osmosis membranes typically last longer than other types of filter elements. Most models need replacement every 2 to 5 years.

As for the other filter stages, make sure to replace the post-filter in a timely manner, since failure to do so will allow residual contaminants to pass into your drinking water.

Here’s the replacement schedule for a typical RO system:

  • Sediment filter: 6 to 12 months
  • Carbon filter: 6 to 12 months
  • Reverse osmosis membrane: Every 24 months
  • Polishing filter: 12 to 24 months


Filters in pitchers last for about 1 to 4 months, after which they need replacement. But if you fill the pitcher multiple times a day, you need to replace the filter even sooner.

3 Water Filter Types

How Long Does a Water Filter Last When Not Used?

Water filters do not expire.

Therefore, as long as they are not being exposed to moisture, they can last forever. Brita explains that the shelf life on their filters is indefinite since they only start their lifespan once they come in contact with moisture.

So, if there’s a water filter sitting unused in your garage, it’s ready for use whenever you want.

Signs You Need to Change Your Water Filter(s)

It’s wise to replace water filters when they reach their manufacturer-specified lifespans rather than waiting for any alarming signs. However, if you notice the following signs, filter replacement is paramount.

Unpleasant Taste

If you do not change the water filter, you will start noticing an unpleasant taste in the water. The nasty taste is due to the presence of foreign particles in the water. If the water tastes like foul or downright dirty, then it is definitely time to change the filter.

Chlorine also makes your water taste awful. So, if your household water has high chlorine content, change the filters periodically.


The presence of contaminants also gives a bad odor to drinking water.

Over time, this can get unbearable. As soon as you start smelling a nasty odor and you haven’t changed your filter in months, it’s time for a replacement.

Drop in Water Pressure

Over time, impurities clog the pores of a water filter, reducing its efficiency. As a result, the water pressure drops since the filter cannot work at its original pace.


Another sign your filter needs replacement is staining. It may begin with the appearance of brown-colored water. This results from rust particles in the water.

Some contaminants in water give it a strange color, such as red or yellow. This is an indication that the water isn’t good to drink and may contain iron, manganese, copper sulfate, arsenic, and other harmful chemicals.

Floaty Mold Bits

If you notice floating bits of dark-colored particles in your drinking water, they’re most probably mold.

Mold in drinking water is hazardous to health and can cause several complications. Moreover, it’s an evident sign that the water filter is old and needs to be replaced.

Slippery Water

If the water feels slippery it’s possibly due to high content of unfiltered impurities.

Some minerals give water a slippery feel, and if they have escaped through the filter, it means the filter is well past its highest efficiency and needs to be replaced.

Small, Odd-Smelling Ice

If the ice is coming out of your refrigerator smaller than usual and has an odd smell to it, that’s an indication for your refrigerator filter to be replaced. In some cases, the ice may have black specks in it.

System Tells You So

Some filters have certain mechanisms like LEDs that alert you when it’s time for a replacement. Don’t ignore the system’s warning, and make sure you change the filter as required.

If you have any questions about how long water filters last and how often to change them please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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