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With so much going on in our lives, you may forget to change your water filter in time. But it’s not just human error; it often gets confusing when to change filters exactly.
That’s what we aim to resolve with this article. Generally speaking, a water filter would last as long as its lifetime mentioned by the manufacturer. But that varies with different types of filters and is also influenced by your water quality and usage.
We’ll discuss everything you need to know about water filter lifespans here.
So, here is our guide answering the questions, how long do water filters last and how often to change them!
- 1 Why Change a Water Filter in the First Place?
- 2 Factors that Influence the Lifespan of a Water Filter
- 3 How Long Does a Water Filter Last?
- 4 How Often to Change a Whole House Water Filter?
- 5 How Long Do Water Filters Last if Unused?
- 6 Signs Your Water Filter Needs Replacement
- 7 Conclusion
Why Change a Water Filter in the First Place?
Well, this shouldn’t even be questioned. But if you’re wondering why you need to replace water filters, here’s the answer.
Water filters have a limited life after which they don’t function as effectively. As a result, bacteria and other contaminants may make their way through the filter and enter your water supply. That essentially kills the main purpose of installing a water filter, i.e., getting safe and pure water.
If the contaminants are large in size, they can even clog your sinks and drain, causing flooding; and that would be a nightmare.
More importantly, the contaminants in your drinking water can impact your health negatively. So an old and expired water filter will be just as good as no filter at all.
To summarize, you must replace a water filter in due time if you want to avoid trouble.
Factors that Influence the Lifespan of a Water Filter
How long your water filter lasts depends on a number of factors:
1. Filter Type
First and foremost, the type of water filter determines its life, as some are more long-lasting than others. Their construction, filtration method, and size all contribute to their lifespan.
Here are rough estimates for different types of water filters:
- Sediment pre-filter cartridges in a whole house water filtration system, for example, may last a few months only, while the large media tank can last 5-10 years.
- A carbon block post-filter in a reverse osmosis system may last up to two years.
- Faucet water filters need replacement every few months.
- Pitcher filters have the shortest service life and only last 30-120 gallons of water usage on average.
2. Your Water Quality
The more dirty and contaminated the water, the quicker the filter expires. On the contrary, if the water is already pretty clean and carries only a handful of impurities, the water filter will last longer.
If the filter is too overworked and dysfunctional, it may even leave residue behind, which can hamper the functionality of new filters. So make sure to get rid of this residue before you replace any filter cartridge.
3. Your Water Usage
The actual water usage in your home also drastically impacts the life of your water filter. That applies to both point-of-entry and point-of-use units.
The water usage, in turn, depends on the number of occupants and bathrooms in the house. If you have a bigger family, your water filter will have to work hard all the time. Naturally, it will reach its end sooner than the designated lifespan.
In such a case, you may need to ignore what the manufacturer has recommended as the time limit for replacement and change sooner.
How Long Does a Water Filter Last?
The life of a water filter can be indicated by time (months or years) or quantity (gallons of water). In most cases, it’s the latter unit, which basically means you have to replace the filter after it has filtered a certain amount of water.
Suppose a water filter has a lifespan of 500 gallons. Now, if you use 10 gallons of water daily, the filter would need replacement after about one and a half months.
Pre-filters usually have the shortest lifespans, lasting three to six months. This applies to both sediment and carbon pre-filters. Post-filters have a lifetime of up to 1-2 years. The main treatment stage of a water filtration system can last up to several years if it’s tank-based. Cartridge-based water filters have a shorter service life.
It’s important to note these timelines are for individual filters or cartridges only. In most cases, you don’t need to replace the whole system; just replace the filter element in question.
For example, if your pre-filter is clogged and needs replacement, your carbon filter might still be doing well.
No matter how compact or efficient countertop water filtration systems are, they are not perfect. Based on the usage of one gallon a day, this type of water filter may last for up to six months. However, some units don’t require replacement until 10,000 gallons have been processed.
Faucet-Mounted Water Filters
Faucet-mounted filters typically require more frequent replacement as these are small and quite heavily used for drinking and cooking. You may have to replace them every two to three months.
Under Sink Water Filters
This entirely depends on your particular model. Generally, under sink water filters can last anywhere from three months to a whole year. You should check your user manual for exact recommendations and the schedule of maintenance.
Reverse Osmosis Systems
Reverse osmosis systems’ main filter is the RO membrane, which has a considerably long lifespan. These commonly last for 2 to 5 years.
However, the other filter stages, the pre and post-filters, require replacement a lot sooner than the membrane. Make sure to replace them timely as you don’t want to damage the membrane or any other system component.
Here’s what a typical reverse osmosis system filter replacement schedule looks like:
- Sediment filter: 6 months to 1 year
- Carbon filter: 6 months to 1 year
- Reverse osmosis membrane: 2 to 5 years
- Polishing filter: 1 to 2 years
Pitchers can only filter water regularly for up to three or four months. That also depends on the use, though, as frequent or daily use may require earlier filter replacement.
Refrigerator Water Filters
If your refrigerator has a built-in water dispenser, it will also have a water filter. This cartridge will require replacement every six months on average. However, newer models may last longer (consult owner’s manual).
Shower filters have a lifespan of about six months. However, that’s only for normal family use. If these are installed in public facilities or hotels, they may need changing more frequently.
Similarly, if the water has too much chlorine, a filter will expire earlier than six months.
How Often to Change a Whole House Water Filter?
Lastly, let’s focus on whole house water filters which tend to have several filter stages, filtering out different contaminants from your water. Such systems generally require replacement after three to six months on average, when cartridge-based.
Large tanks filled with one or more cubic feet of filter media can provide you with filtered water for up to a decade and longer.
How Long Do Water Filters Last if Unused?
Maybe you’re on vacation and haven’t turned on a tap in months; will you still need to replace your water filter according to the general lifespan? No, not really!
Filters don’t really have an expiry date; they just have expiry terms. They only go bad when exposed to water and impurities. So as long as a water filter hasn’t been used, it will not require replacement.
This means that most water filters have indefinite shelf lives. So if you get a good bargain on a bundle, don’t miss out on it! These things can be used anytime, even months and years later.
Signs Your Water Filter Needs Replacement
While you should follow the manufacturer-recommended timeline of water filter maintenance, sometimes your filter may get clogged or stop working earlier for another reason.
You can look for the following signs if you don’t have access to a user manual and don’t know exactly when to change water filters.
If your water is starting to taste bad, your water filter clearly isn’t doing its job. The unpleasant taste is usually because of the presence of dissolved or undissolved chemicals, such as chlorine, or dirt, or bacteria.
If the taste is pretty foul, you need to change the filter immediately, specifically the one that deals with chemicals and solids.
Some contaminants can also make the water give off a strong stench. In case of sulfur, it may smell like rotten eggs. Surely, no one would want to drink bad-smelling water. If this happens after months of not replacing the water filter, you should know the cause.
Water Pressure Drop
This is a common issue in whole house water filters, as when the filter gets clogged, the water flow and pressure drop noticeably. You can also measure water pressure by installing a gauge before and after the system.
Are there dark floating bits in your water? It’s most likely mold. This is a dangerous pathogen that can lead to some serious complications. Not only should you replace the water filter right now, but immediately stop water usage until it’s dealt with.
Rust particles in water can turn it brownish. When this happens, the water leaves stains on dishes, clothes, and the fixtures in your kitchen and bathroom.
If your water has any kind of discoloring, it’s an indication that the filter is not working right. Usually, it’s iron, copper sulfate, or manganese that’s causing these color changes.
If the water feels slippery, it’s probably because of impurities. In other words, your water filter may need replacement as certain substances are bypassing it.
This refers to refrigerator ice. If it’s smaller than usual and smells odd, it’s a sign that the fridge water filter needs changing. Sometimes, the ice cubes have small black spots too.
Advanced water filter systems have built-in indicators that tell you when it’s time to replace the filter stages. Such systems are great as they notify you just in time before anything bad happens.
Normally, it’s an LED light indicating the replacement time. As soon as you replace it, the light will turn off.
If you have such a system, consider yourself lucky and closely follow the indicators to carry out timely replacements.
In conclusion, a water filter loses its filtration capability over time which is why it needs replacement at a certain point.
How long a unit lasts depends on its type, your water quality and your water usage.
Countertop, under sink, reverse osmosis and refrigerator filters tend to last the longest – up to several months to a year. Faucet-mounted water filters, filter pitchers and shower filters usually need replacement every few months.
Whole house water filters vary a lot. Sediment pre-filters can be clogged after 1-2 months while backwashing filter media tanks can serve for more than a decade.
When not used at all, a water filter lasts indefinitely.
The most common signs a water filter needs replacement are bad water taste and odor, a drop in water pressure, floating particles in the filtered water and a overall decrease in output water quality.
Some water filter systems also use filter change indicators to notify you when a filter element has reached the end of its life.
-  https://www.michiganradio.org/post/study-bacteria-can-grow-faucet-water-filters
-  https://www.wqa.org/Learn-About-Water/Perceptible-Issues
Rory has joined the Water Masterz team as a contributing writer. He has covered all sorts of topics in the last several years.
Outside of his writing work, Rory enjoys photographing the Irish landscape and making music!