House & Beyond is reader-supported. We may earn a commission through products purchased using links on this page. Learn more about our process here
An inline water filter is a small but handy appliance which you can simply install directly to your cold water main line and then forget about it! Best for those looking to access cleaner and a contaminant-free water supply, they’re also favored by those looking for instant filter solutions in caravans, motor homes, and boats. The best inline water filter allows you to keep your existing kitchen tap/faucet and they replace the need for a large under sink filter. They also work well in refrigerators and water coolers.
This review looks at no less than ten of the best rated inline water filters available on the market, as well as highlighting our Editor’s Choice product, the CuZn UC-200 Under Counter Water Filter. Looking at features that we consider the most important, we focus on where these filters can be installed, what their capacity and life expectancy are, their flow rate and their overall dimensions.
By undertaking such research, we’ve been able to present those products we believe offer the best value and performance for a reasonable price. Giving all this information in an easy to access table, we provide an in-depth review of each model chosen, alongside an important buying guide so you can get the most out of your purchase. We also attempt to answer a couple of the most commonly asked questions relating to these products. When combining all this information, we believe you’ll be able to select that best inline water filter to suit your individual requirements.
The CuZn UC-200 Under Counter Water Filter is our Editor’s Choice as it combines a fantastic performance with a very generous filter life capacity. Ready for installation under the sink or in refrigerators and suitable installing in RVs, this USA-designed and made product offers an ultra-high capacity, giving you access 50,000 gallons throughout its filter life. Providing a flow rate of two gallons per minute, you could possibly be looking at a lifespan of five years using this model! In addition to such a long life span, this also comes complete with a five-year pro-rated warranty, alongside a standard 90-day satisfaction guarantee. This is a water purification system which is perhaps one of the better of models to install with ease. All you need to do with this is connect it directly to your sink cold water line. All that’s needed is an adjustable wrench to tighten the connection, and it can be completed in just a few minutes. You could even access the installation video, which now comes with this purchase. Offering a fantastic three-stage filtration process which purifies without removing beneficial minerals, this ensures a bacteriostatic filtration system which is not susceptible to bacterial growth or mold.
Customers of the CuZn inline water filter find it not only the easiest of models to install, but equally believe it to work exceptionally well filtering the water.
What do we love it for?
Huge filter life!
Five-year pro-rated warranty
Ease of installation
Three stage filtration process
Fantastic customer service from CuZn
What were we disappointed with?
Some suggestions of persistent cloudy water remain
Our vote for the best inline water filter system goes to the iSpring CUA4. This is an excellent product which offers the most superior of four stages and is a unique multipurpose water filtration system. The result is not just better tasting water all-round but most importantly, water which is safer and indeed healthier for all who consume it. By utilizing a four-stage design, you can access the best ultrafiltration process possible as the KDF/GAC stages included ensure you get the most effective water filtration in its class via this filter solution! With claims that it can work to remove a staggering 99% of those most problematic pollutants, it also ensures that it keeps back those healthier of minerals as it does this. Therefore, it will work to remove things such as bacteria, chlorine and chlorine treatment by-products, lead, arsenic, giardia, and much more besides. A simpler idea but one that is most effective in use, this is also a compact and flexible filter which means it can be used for a variety of practical solutions as well as under the sink. Therefore, it’s excellent for use in the RV, under the sink, in the refrigerator and even for use in some coffee machines! Simple to install and even more straightforward to maintain, these cartridge types will just twist on and off.
Customers of the iSpring CUA4 inline water filter find that it encourages a wealth of better-tasting water all-round, as well as being one of the easier of filters to fit and use in an instant!
One of the best inline drinking water filter products reviewed here, the Woder inline water filter also gains Amazon’s choice award for the best water filtration system. This is an ultra-high capacity model which you can connect directly under the sink. It, therefore, doesn’t require any plumbing beforehand as it comes with a direct connect hose that will fit under most standard US kitchen and bathroom sinks. The idea is to easily install it directly on the existing cold water balance and faucet stem, which is located under the sink. The result is pure and healthy water all-around, which reduces the need to keep those annoying bottles in the fridge. This fantastic concept also ensures that it will last for 10,000 gallons, which is around a staggering three years in total, dependent on your usage levels. This is almost as much as six-times longer than most standard filter types offer. What’s more, this model provides what is known as selective filtration. Therefore, it boasts of a unique technology that aims to remove as much as 99.99% of contaminants present but all the while leaving in those most essential of minerals. This is referred to as reverse osmosis whereby everything that is not required is filtered out, while everything needed is kept back. This means your tap water comes out tasting like that of spring water!
Customers of the Woder inline water filter find this an excellent purchase whereby it makes filtering water in the home much more accessible, and, indeed, better-tasting as a result.
Why are we impressed?
Good filter life
No plumbing required
Produces spring freshwater taste
Selective filtration process
What negatives must you be aware of?
Some mentions of decreased water flow when in operation
The APEC inline water filter is our pick for the easiest to install inline water filter as it comes complete with a trouble-free installation process. This means it offers standard 3/8 hoses which directly connect to your existing cold water valve as well as your faucets stems. This ensures that there are no holes to drill as a result. In addition to the easy installation process, when you do need to change this filter, all you need do is access the quick twist connection design and filter replacement is instant. Constructed using a supreme quality throughout, this is designed and engineered in the USA and includes the exclusive US made filter. All components are made up to the highest and most trusted of filtration capabilities when compared to numerous other products in this category. With the aim of removing chlorine, lead, heavy metal, bad taste, odors, and other chemicals, it also works hard to ensure that those various minerals that are actually good for us are left behind. These include things such as potassium, calcium, and magnesium. This makes it ideal for using for cooking, washing vegetables and fruits and also when cleaning dishes as it doesn’t leave behind any visible watermarks. Above all, this does all this and more while allowing you to gain clean, purified water directly from your existing faucet, therefore eliminating the need for separate taps or inlet valves.
Customers of the APEC inline water filter state this is one of the easiest of filters to apply and offers a good source of water flow throughout.
Our choice for the best inline water filter for RVs
is the AQUACREST RV Inline Water Filter. This is perhaps one of the more affordable inline water filter types, but equally one of the most effective when it comes to removing anything negative you may find in your water supply when traveling in the RV or indeed in your boat. This includes those heavy metals, fluoride, chlorine, and arsenic. Sold in a pack of two for increased practicality, it is claimed you can get a grand total of three months from these filter types, therefore increasing it to around six months with this double pack. Utilizing a high-grade filtration material, the idea here is to ensure that you’ll always have that most refreshing and safe water at all times. Furthermore, this has been designed to provide a leak free fit and therefore makes installation simple. Though the company also suggest it can be used for gardening and even car washing when used in RVs and on boats, you can have instant access to greater tasting water from your tank rather than having to continually rely on purchasing cases of water and therefore carrying an endless supply of bottles with you on your journey.
Customers of the AQUASCREST RV inline water filter find water taste significantly improves with this model, but also like the benefit of a faster water flow rate as well as its increased filtration effect overall.
The Frizzlife makes it onto our list for the Best Powerful Inline Water Filter as this is a bigger and more powerful of choice both in stature and what it offers as a whole. This has two phases of a highly precise type of compound filter, which includes some of the most unique technology. With the intentions of removing a staggering 99.99% of contaminants found in most water supplies, this also resolves to leave all those most essential of minerals in the process. With a fully inclusive package, you’ll also find a converter, two wrenches, water tape, three screws, one inlet hose, and an outlet hose. So, you can enjoy pure and indeed healthy water straight from the tap. This directly connects to your under sink water supply and doesn’t need any plumbing to do so. This means that you can install this model within a space of just three minutes’ tops, and all without even having to switch off the water supply. Therefore, replacing it is almost child’s play! An excellent idea for using when cooking, washing vegetables and fruits and cleaning dishes properly, this is thoroughly a money-saving device.
Customers of the Frizzlife inline water filter highly rate the ease of installation while considering it the best choice for great tasting drinking water.
The PureWater Inline Water Filter Kit gets our vote for the best inline water filter for an ice maker. This filter improves the taste of your water by way of removing any chlorine taste or odors present. It also aims at reducing the cloudiness that is often caused by slow freezing. A more economical option overall and with an ability to fit it to most ice makers, this is also one of the easier of filters to install. This comes complete with quick connect fittings, which means you can access results in minutes! This model features a new filter type, 15 feet of a ¼ inch NSF certified water line, a ¼ inch shut off value, two quick connect water line adapters, a mounting bracket with accompanying screws and complete installation instructions with graphics included! Furthermore, the company state that this comes complete with a PureWater filter promise – therefore, it gives a lifetime warranty for any defective or malfunctioning parts alongside lifetime telephone support, which is free! Though flow rate is not specified here, this complete kit does offer a good filter life of 1500 gallons. It is worth noting here though that this product is purely an ice maker model and not suitable for use under a kitchen sink!
Customers of the PureWater inline water filter find this one of the easiest to install and offer some high ratings for its ability to make the water taste noticeably different than before.
The Watts product has our vote for Best Maintenance Free inline water filter. Ideal for use in a variety of areas, this is effective for refrigerators and ice makers that are both residential and commercial, coffee and tea brewers, water fountains, motor homes and campers! With a functional capacity of 20,000 gallons in total, this has excellent compatibility and works really well with almost all water supplies using those ¼ inch lines. A most lightweight of inline filters at just 3.5 lbs, it includes with the purchase two ¼ inch connectors and is designed to fit with ease to the existing plumbing arrangements. Better still, this is a thoroughly maintenance-free product, therefore all you need to do here is cast an eye over it for inspection every six months, leaving it to do its magic in the meantime! The concept of this water filter is to work on reducing the harmful element of water supplies such as chlorine, contaminants, odor, sediments, and any particulates. The result is drinking that which is not only better tasting, but also a healthier choice. In addition to such properties, this also works hard to reduce the scale build up that is a problem in many an appliance. It, therefore, works to inhibit bacterial growth as it does this.
Customers of the Watts inline water filter claim this is one of the longest lasting of water filters that creates an all-around better tasting water supply that eliminates all previous lousy taste and rancid odors and is one of the easier of models to install.
The Omnipure is our choice for the best inline water filter for the refrigerator as it is one of the simplest of water filters on this list. Therefore, it’s the easiest of products to install and use in not just the refrigerator, but also in ice makers, drinking fountains, under the counter systems and in some beverage equipment. With a good filter life of 1500 gallons in total, this is very well priced and available in packs to suit. Designed with an aim to reduce that chlorine taste and odors that often persists in the water supply, this filter has quick ¼ connect fittings included which makes it the easiest to not just install, but also makes it straightforward when it comes time to replace it. Better still, because of its ease of installation, no tools are required here. An extremely lightweight product, it weighs a mere 12 ounces and works on a small assembled diameter of just two inches total. When you receive the filter for installing, all you need to do is remove the cap that sits at the ends of the filter while pushing the line into it. It will then automatically lock it and seal it for immediate use. Most people suggest it takes a few minutes maximum to do this.
Customers of the Omnipure inlet water filter state that they really can tell the difference when they begin using this product. A thoroughly incredible money saver, it also claims to offer great value as well as being one of the easiest of water filters to fit within a short space of time.
The LASCO 37-1813 is our Budget Pick of the bunch and is sold at a fantastic lower price. An extremely straightforward type of inline water filter, this is a universal size and therefore can fit the majority of sinks. This model offers a great filtration capacity, especially at this cost, capable of filtering around 2000 gallons’ worth of water. With the idea of providing the ability to filter the taste in the water supply, this may weigh a mere 12 ounces, but it offers strong properties throughout. Furthermore, it is backed up by a one-year warranty. LASCO is well-known throughout for its selection, service, and support, and the family-owned company has been in operation for well over eight decades! Furthermore, this is a company who is one of the most extensive retail plumbing lines in today’s industry. One of the more basic of product types, this water filter works to improve the taste of the water you drink all the while offering an adequate life expectancy as it does so. One of the easiest to attach, fit, and then immediately use, it’s perhaps its ease of inserting under the sink that makes it one of the more popular of choices for many customers.
Customers of the LASCO inline water filter seem perfectly happy with this no-frills product and find that it works exactly how it should do, with no complaints
What stands out?
Fantastic filter life
Great universal fitting
What cons did we manage to find?
More simplistic of models
Things to Consider
Now that you’ve been able to read through these detailed reviews, you should have a better idea of what the best inline water filter can do for your needs. However, just before you make that final purchasing decision, why not take a few minutes to read through the additional buying guide we have attached here? This section is designed to elaborate a little more on those important features we touched on above. By the end of this guide you should have everything that you need to help you select the best inline water filter possible and therefore spend your money wisely on your purchase.
How will an inline water filter improve my water?
Many people will select an inline water filter predominately for the basis of improving the water they drink. If this is of importance to you, an inline water filter is said to offer some fantastic benefits including:
Removing those contaminants that are unfortunately often found in general water supplies. These include things such as chlorine, chromium, volatile organic compounds, lead, heavy metals, mercury, carcinogens, and many more besides
Removing harmful contaminants while leaving behind essential minerals in the meantime
Improving the overall taste of your water significantly
Removing any odors present in your water
Encouraging improved skin health as a result of a cleaner and healthier water supply
Reducing the visible stain of watermarks on dishes and cutlery due to a reduction in limescale build up, therefore equaling a non-scaling water supply produced throughout
Features to consider when choosing an inline water filter
Though it may seem as though choosing an inline water filter is initially straight forward, upon closer inspection you’re bound to find those additional features that apply more to your specific reason for using such a product. Though there are other added benefits when you search the marketplace here, we recommend that you do look toward those most essential of features to start. This includes considering where you’ll be using the filter, what media and filtration stages it offers, what the life expectancy of it is, the rate of its flow, its overall dimensions, weight, and warranty, alongside how easy it is to install.
Where do you need it?
First things first, where and how do you intend to use your inline water filter? This is perhaps the most important question because you need to make sure before you spend your money that the type of filter you purchase can actually fit in the space you need it to, as well as work to offer everything you need from your filter choice.
As you can see from the inline water filters reviewed above, there is a selection of filter types available, and some may cater more to specific areas than others. Look towards the filter type initially. Is it a universal type, allowing plentiful choices such as the LASCO? Is it an under sink type, such as the more common of options, like the Watts and Frizzlife? Or is it a more specific type aimed at ice makers, RVs, boats, refrigerators or even ice makers, such as the PureWater, AQUACREST and Omnipure K2533JJ, for example?
Filter media and filtration stages
When looking at inline water filters, you’ll often discover that they are composed of a whole variety of different types of filter media. This is merely because they have various purposes in ridding of nasty chemicals, keeping hold of those essential minerals and even working to reduce limescale while encouraging more beneficial flow rates! Therefore, you’ll notice they rely on a blend of media and more than likely some form of activated carbon.
The filter life is usually referred to as the number of gallons present in that particular model. Therefore, the higher the number here, the longer your inline water filter should last you.
However, note that this can often vary depending on how often much water you consume.
Therefore, you may find the length of time a filter lasts you is vastly different from others who use the same product if your usage and needs vary greatly here.
Sometimes, you’ll find an average time estimate quoted next to your particular model, and this can range from a few weeks to many months. The CuZn UC-200, for example, offers 50,000 gallons, which means you could get up to almost five years of use from just this one filter! In addition to this, the APEC CS-2500 suggests a life capacity of around a whole year. Therefore, double check the finer print and if you need to, look for those that offer more than one filter in your initial purchase.
Inline water filters are fantastic when it comes to supplying an excellent, consistent flow even in low flow environments. In short, they aren’t as fussy when it comes to water pressure requirements! Therefore, they are often the favorite choice for those places such as caravans, boats, and RV’s, for example, whereby low flow environments are always deemed more problematic.
When searching for the better filter that will encourage an improved flow rate, look toward the GPM figure, that is the gallons per minute. This figure will tell you how many gallons will flow through your inline water filter each minute. Therefore, the higher the number here, the better. The highest GPM rate here at 2GPM comes from the CuZn UC-200, Woder, and Frizzlife.
A most practical of areas to consider is the dimensions of your filter. Though these do tend to be the smaller of products overall, they do vary in size and structure, especially if they are designated to be used in specific areas. Therefore, if you are in an RV for example, you wouldn’t want to buy a filter only to find when you come to fit it, it’s more suitable for larger spaces in the home!
We suggest gaining an idea of the space you have available for your inline water filter before you make your final section. Get the measurements available first to ensure this won’t be a problem.
We’ve made sure to include all the dimensions of every inline water filter reviewed here, showing them in inches for you to ensure a perfect fit beforehand.
Once again, as in the case of dimensions, you may want to pay closer attention to the weight of your inline water feature. As we’ve said before, these products are usually the smaller and lighter of items, but this is only so when they are used in the right circumstances. Therefore, if you are shopping for a water filter for the home, you can perhaps afford to forgo the issue of weight here. However, if you’re selecting a model for use in the caravan, RV or even in a small ice maker, you may want to look for those that are lighter for this purpose.
Installation: fittings and hoses
In general, inline water filters tend to be the easier of product types to install. Furthermore, if you can find those models that also come complete with quick connect fittings as standard, your installation should be faster and take no longer than a few minutes.
This will also then apply to each time you replace the filter, and should you need to access the filters during any routine maintenance.
Therefore, check that your water filter comes with the necessary fittings and hoses, for example, so you don’t have to search for extra items just to install it, neither do you need to have an extensive amount of plumbing experience beforehand.
We’ve made sure to include those easier of installation filters to get you up and running immediately after purchase.
Though it may not be a product type whereby an attached warranty immediately springs to mind, if you’re considering spending quite a bit of money on your inline water filter you may want to think about whether it comes with a standard company warranty, for extra peace of mind.
As you can see from the above reviews, we have mentioned in the extra features section those water filters that offer a warranty worth highlighting. For example, for a budget pick, the LASCO provides a fantastic one-year warranty, and CuZn give a tremendous five-year warranty for their filters! This may be more of personal preference, but if it’s something that you feel you may want to find as standard when you make your purchase, many inline water filters do offer ongoing confidence through some great standard warranty types.
How to improve your filter’s performance and lifespan
Be sure to read and follow the exact manufacturer guidelines that come complete with your water filter
Try to avoid exposing your filter to extreme hot or cold temperatures regularly to prolong its life and function
Make it a habit to check on the progress and state of your filter on a regular basis. Though it may not necessarily need regular maintenance, you should also ensure it is running at its most efficient and is not damaged in any way over time
Finally, avoid using your product with very harsh water if the filter itself is not designed exclusively to handle this
For best practice, we always recommend using those more neutral temperatures when you have an inline water filter fitted. This means steering clear from temperatures that are too hot or cold. This is because most filters cannot cope with such surges of increased heat and large fluctuations over some time.
You may notice on closer inspection that most models such as these reviewed here will mention that such filters should not be used for well water. This is merely because they are not designed with this purpose at their core. If you need a filter for well water, it’s best to look for one that has been designed with this purpose in mind.
The gallons suggested by each manufacturer refers to the filter lifespan and should be used as a guideline. This is because you cannot be guaranteed to get that exact amount as many factors may change the timeline here. This can include in general how much water you tend to use on average in your home or where the filter is installed. As a guideline, we suggest aiming for the higher gallon figures where possible but being mindful of when you may need to change this, in particular, if you notice any reduction over time in the flow rate or water pressure.
Now that you’ve had a chance to read through some of these fantastic reviews, you’ll have a clearer understanding of what makes the best inline water filter. You may also now have a better idea of which one from this list would most suit your individual circumstances and needs!
We have three favorites on the list here. First place and our Editor’s choice goes to the CuZn UC-200 Under Counter Water Filter. We believe this offers as much as you could possibly need from your water filter including a superb filter life, a brilliant long term warranty and all coupled with some of the most fantastic filtration results possible! In second place is the iSpring CU-A4, which makes our list for the best inline water filter system, namely because it delivers an exceptional and focused filtration process which is unbeatable. Third place is Woder 10K-Gen3 Inline Filter, which we liked for its selective filtration and extended filter life.
In concluding, we’ve hopefully proven that these products are unbeatable when it comes to getting the purest and best tasting water possible wherever and whenever you choose to utilize them.