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Home » Water Filtration Systems » Best Under Sink Water Filters Reviewed

Best Under Sink Water Filters Reviewed

By: Stephanie Nielsen
Last Updated:
best under sink water filters

Are you worried about what is in your drinking water? Or are you tired of buying bottled water?

You’re not alone.

In fact, a lot of people are very concerned about the quality of the water they consume every day.

While there are some ways to improve the quality of your home’s water, one way that many people don’t think about is getting a water filter.

We have spent countless hours researching, talking to manufacturers & customers, learning about new technologies, and testing different filters to determine which under-sink water filters are the best for clean drinking water. 

In this review, we will outline the top under sink filters on the market, and explain why they made the cut. 

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Top 10 Under Sink Water Filtration Systems

#1 Clearly Filtered 3-Stage
  • Filter Stages: 3
  • Dimensions: 13.75 x 3.5 x 16.75
  • Other: Quick DIY install & Lifetime Warranty
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#2 Waterdrop G3
  • Filter Stages: 7
  • Dimensions: 18 x 5.7 x 17.8
  • Other: Most powerful filtration with RO
#3 Aquasana OPTIMH20
  • Filter Stages: 6
  • Dimensions: 12 x 4.5 x 12.5
  • Other: Great filter with RO
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#4 Aquasana 3-Stage Max Flow
  • Filter Stages: 3
  • Dimensions: 12 x 4.5 x 12.5
  • Other: Fast water flow & top brand
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#5 Waterdrop 3-Stage Black
  • Filter Stages: 3
  • Dimensions: 15 x 5 x 14
  • Other: Zero waste & quality filtration
#6 ECO Soft 3-Stage
  • Filter Stages: 3
  • Dimensions: 15 x 5 x 14.5
  • Other: Affordable filtration
#7 iSpring RCC7AK
  • Filter Stages: 6
  • Dimensions: 15 x 8 x 18
  • Other: Reverse osmosis option
#8 CuZn UC 200
  • Filter Stages: 3
  • Dimensions: 5 x 5 x 15
  • Other: Compact option
#9 APEC WFS 1000
  • Filter Stages: 3
  • Dimensions: 6 x 15 x 12
  • Other: Middle of the line

Criteria to Consider When Buying an Under Sink Water Filtration System


With under-sink water filters, these are the criteria we considered and that you should consider when deciding which water filtration system to go with to get clean drinking water every day.

Contaminants Removed

The main purpose of purchasing under-sink filters is to filter out the contaminants in your tap water. So, you need to make sure it can remove the specific impurities you’re dealing with.

If you don’t know what contaminants you need to remove, be sure to test your water using a high-quality water test kit.

The specific contaminants that a filter can remove vary from model to model, but in order for it to be deemed suitable for drinking water it must meet these standards at the very minimum.

With under-sink filters, the most common types of filters used are carbon, reverse osmosis systems, and ion exchange. The specific types and number of filter stages will determine exactly what the unit can remove during the filtration process, including volatile organic compounds.

Common Filter Types in Under Sink UnitsContaminants Removed
Carbon (Block or Granular)Chlorine, taste and odors, asbestos, lead, mercury, VOCs, trihalomethanes, disinfection byproducts, some microorganisms
Ion ExchangeMinerals (calcium, magnesium), barium, radium, heavy metals
Reverse Osmosis (Most Effective)Most microorganisms, minerals, heavy metals, suspended particles, fluoride, arsenic, nitrates, hexavalent chromium, perchlorate, VOCs, most radionucleotides

Replacement Filters & Lifespan

Under sink water filters are generally designed so that you replace the filter cartridges every so often.

This can be done without a plumber, and most filters should be replaced every 6-12 months. 

The main things that affect your filter’s lifespan are:

  • The type of water filtration system
  • How much you use it
  • The number of contaminants in your water (which you should have determined already)

Overall, you want to look for a water filtration system that is durable and which you can easily replace only once every 6-12 months if possible.

Pure Water to Waste Water Ratio

Reverse osmosis style filters use water to flush away the contaminants they filter during the filtration process. This water has a higher contaminant concentration and is considered non-potable (meaning it isn’t fit for drinking) or water waste which is not eco-friendly. 

On average, RO filters use four gallons of wastewater for every gallon of fresh water generated, and systems that can minimize this waste are ideal.

Relative Price

When comparing the price of under-sink filters, there are two main things to take into consideration:

  1. The cost of the system and its initial installation
  2. The cost of the replacement cartridges

For example, you see a filtration system that costs only $150, but it needs a plumber to install for $100 and the cartridges are $150 to replace yearly. At the end of five years, you’ll have spent $1,000. 

On the other hand, you may see a drinking water filter system that costs $400 upfront but doesn’t require a plumber for the installation, and the cartridges are only $75 per year. 

If you go with this one, even though it’s more upfront, at the end of five years you’ll have only spent $775. 

Don’t forget to look at the long-term costs and savings of the systems you’re considering as well as the quality of filtration.

Flow Rate

Something else to consider is the effect that the filtration process has on your flow rate. The flow of water is measured in gallons per minute or GPM, and it describes your faucet’s water pressure or how fast it comes out. 

One of the biggest complaints people have about their under sink system is how it negatively impacts the flow velocity.

There’s usually a trade-off between the level of filtration and flow. 

RO filters have a notoriously low rate of flow – but that’s because they filter out the smallest particles. An ion exchange filter has a higher flow velocity, but it doesn’t remove the same amount of contaminants.

The best under-sink water filter will meet the quality standards you need for your water while still maintaining a functional flow.


There are two independent, 3rd-party associations that certify water filters – the National Sanitation Foundation (NSF) and the Water Quality Association (WQA).

If a filtration system is certified by either the NSF or WQA, it’s an extra assurance that the filter meets high-quality standards. 

RO filters, for example, may be certified for the NSF/ANSI 58 standard which evaluates things like the filter’s structural integrity, efficiency, contaminant reduction performance, and other criteria.

A carbon block filtration system, on the other hand, may be certified for the NSF/ANSI 53 standard, which evaluates the under sink filter’s ability to remove materials with detrimental health effects. 

For more information about water filter certifications, click here.

Ease of Installation

This is an often-overlooked factor when it comes to buying an under-sink filter, and one which you won’t usually find reliably described on the box.

The cost of engaging a professional plumber to install an under-sink filtration system is certainly going to outweigh any savings gained by opting for a cheaper under-sink water filter. 

While most manufacturers will downplay the complexity of installation, only first-hand user experience from customer reviews will give you a true picture of the ease with which water filters are installed.

Best Under Sink Water Filter Reviews 

Under sink water filter

Review Order

Using our evaluation criteria above we selected the best under-sink water filters on the market which we have reviewed in detail below to help you decide which filtration system is best for your kitchen needs.

1. Clearly Filtered 3 Stage

clearly filtered under sink

Our #1 recommendation for the best under-sink water filter is the Clearly Filtered 3-stage water filter system.

Clearly Filtered has a history of producing superior products that deliver quality results, and this product is a prime example:

  1. It removes the most contaminants of any residential filter
  2. It’s NSF certified
  3. You can install it yourself
  4. It comes with a lifetime warranty.

This sink water filter system has three stages of water filtration including a premium carbon priming filter, a heavy metal and VOCs (volatile organic compounds) filter, and a fluoride and arsenic filter.

The carbon priming filter contains granulated coconut carbon which removes chlorine, tastes, odors, cloudiness, and colors.

The heavy metal and VOC (volatile organic compounds) filter remove 99% of heavy metals, pesticides, and herbicides, and the fluoride and arsenic filter removes 99% of fluoride.

The filtration capability of this under-sink filter is one of the best in removing more than 200 contaminants.

This under-sink filter also comes with a pretty solid filter lifespan at around 2,000 gallons of water or around 12-15 months before needing replacement and the replacement filters are a breeze to install.

Lastly, this is one of the easiest under-sink water filter systems to install. They claim anyone can do it and it takes only 5-10 minutes.

Main Features & Benefits

Contaminants removed: This filter removes 99.7% of 232+ contaminants – more than any other system on the market.

Contaminants removed include fluoride, chlorine, perfluorinated chemicals, pharmaceuticals, herbicides, semi-volatile compounds, heavy metals, VOCs, radiological elements, and pesticides. 

You can click here to see all of Clearly Filtered’s test results.

Filter lifespan and replacement: One of the best things about this filtration system is that Clearly Filtered offers a lifetime warranty on it, so even if something goes wrong you can rest easy knowing there won’t be any extra expense. Otherwise, this filter has a 2,000-gallons of water filter life and is made with stainless steel hoses that offer extra durability.

Flow rate: Several customers have reported that this filter cuts your cold tap water flow roughly in half. Compared to many back osmosis filters, however, you get a higher flow velocity than you would with those while still achieving the same level of water purification and filtered water. Not to mention, there’s no waste water, either.

Certifications: Clearly Filtered systems have been NSF certified.

Price: While the $500 price tag may cause some sticker shock, you instantly get $100+ back in the installation. This filtration system is able to be DIY installed in 15 minutes or less without a plumber. The simplicity of installation can’t be overstated, which also makes it the perfect solution for renters because it’s easy to remove and not permanent. 

Another thing to consider with the price is the lifetime warranty. While you might have to pay $250 for one system now and another $250 when it breaks in 10 years, you can rest assured that Clearly Filtered has you covered. 

At $400 every 9-12 months, the filter replacement cartridges aren’t cheap either. When you compare them to the other under-sink systems at a similar price point, however, you’re paying the same amount for higher-quality water.


  • Filters out 99.7% of 232+ contaminants from your water supply
  • Lifetime warranty
  • Top of the line 3 stage filtration
  • Super easy to install and replace
  • Filter life 2,000 gallons
  • Just as good or better as a system with RO
  • NSF certified 
  • Sleek design – doesn’t take up much cabinet space


  • Not cheap but worth it for a lifetime warranty and quality
  • 50% reduction in flow velocity of the cold water line

Bottom Line:  All in all, if you’re looking for the best under-the-sink filter for your home then you need to purchase this Clearly Filtered model. You won’t be disappointed.

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2. Waterdrop G3


Another one of our top picks for the best under-sink water filters is the Waterdrop G3 reverse osmosis filter system. 

Waterdrop is becoming a top brand in high-quality innovative water solutions and this model is one of their best products.

This is one of the most powerful under-sink water filter systems with an impressive 400 gallons per day capacity, which would suit even a large household.

The powerful RO system removes 99% of TDS, it’s NSF certified, and it fits nicely under your sink. 

The Waterdrop G3 has a 7-stage filter system, making it one of the most effective and thorough water filter systems on the market. These are the following stages and components:

  1. Pre-sediment and carbon block filter (made from granulated coconut with PP cotton, removes sediment and cloudiness, chlorine, and other bad odors and tastes)
  2. 3-stage Reverse osmosis filter (DOW reverse osmosis system has a 0.0001-micrometer pore size to filter out even the smallest contaminants)
  3. Post-activated carbon block filter (refines the taste, odor, and color)

This sink water filter also reduces wastewater by 300% more than other RO units, which is more eco-friendly, the filters are easy to change, and it has the highest level of new technologies.

Main Features & Benefits

Contaminants removed: The Waterdrop G3 removes 99% of the total dissolved solids in your water using the RO system. 

Contaminants filtered include chlorine, foul tastes and odors, suspended particles, limescale, and other minerals, heavy metals, microorganisms, and other harmful contaminants.

Filter lifespan and replacement: Depending on your household size/water usage and the number of contaminants in your water, each set of carbon cartridges should last you 6-12 months while the RO cartridge can last up to 24. This kitchen sink system also comes with a one-year warranty to protect against manufacturer defects.

Filter replacement is easy, and the filters are available online. The integrated composite filter not only enhances the filtration performance but also reduces the number of cartridges. This will bring a lower replacement cost and easier maintenance.

Flow rate: This water filter system has a rate of flow of 400 gallons of water per day, which means it takes roughly 12 seconds to fill a cup. While this may seem like a low flow velocity, it’s faster than many other back osmosis filters on the market.

Fresh to waste water ratio: Unlike traditional RO systems, this filter has a 1:1 drain ratio. Many people are concerned about the amount of wastewater a RO system produces, but the G3 system has a low drain ratio meaning that for 1 gallon of purified water, it only produces 1 gallon of wastewater.

Certifications: This product has been NSF certified for 400+ chemicals. 

Price: The initial filtration system may set you back a bit at $545, though the good news is that you don’t need a plumber to install it. After that, you can replace all three cartridges for under $135 so you do end up spending less in the long run. 


  • The 7-stage filter removes 99% of contaminants 
  • Uses RO filtration
  • Largest capacity & most powerful system
  • Compact, tankless design that fits well under sink
  • 400 gallons per day rate of flow
  • Designed for DIY, this system is very simple to install


  • One of the more expensive under-sink filter systems but it’s worth the investment, and the replacement cartridges aren’t too pricey

Bottom Line:  If you’re looking for an under-counter option that uses RO filtration to get your water pure and clean, then this water filter system from Waterdrop is your ideal choice.

3. Aquasana OPTIMH20 RO+ Claryum

Aquasana Optimh20

Another one of our top picks is the Aquasana OPTIMH20 RO and Claryum filter. 

This water filter system also utilizes RO but is more sparing on your flow velocity, it removes over 87 contaminants, is NSF certified, and is a more budget-friendly option. 

Aquasana is another one of the leading brands in the water filtration market and they produce reliable, top-quality products that you can rely on to get clean water.

This under-sink water filter system model from Aquasana is a RO system, and it incorporates six different stages of filtration to remove over 89 different contaminants:

  1. RO filter (removes dissolved particles smaller than 1 micron such as arsenic and fluoride)
  2. Activated carbon filter (acts on organic chemicals and VOCs like pesticides)
  3. Catalytic carbon filter (removes chlorines and chloramines)
  4. Ion exchange filter (binds heavy metals in the water)
  5. Absolute sub-micron filter (removes protozoa cysts and asbestos)
  6. Remineralization (adds healthy minerals back into the water to make it more alkaline)

It comes with filters that will last from 6-12 months, an average rate of flow, and a high level of filtration capability.

The only downside with this sink water filter system is the wastewater it produces at 4 gallons of waste to 1 gallon purified ratio.

Main Features & Benefits

Contaminants removed: This model from Aquasana provides premium filtration technology with RO. It’s tested and proven to remove fluoride and 87 additional contaminants. 

Filter replacement and lifespan: You can expect the RO membrane and the remineralizer to last roughly a year before they need to be replaced, and the other cartridges have a 6-month lifespan on average. The cartridges are very easy to replace, and the system comes with a 90-day guarantee and a 2-year warranty. 

Flow rate: Compared to the Waterdrop G3, this filter has a rate of flow of 720 gallons of filtered water per day or 0.5 GPM. The heightened flow velocity is due to the larger pore size of the RO membrane, so while the Waterdrop filter removes more contaminants this one maintains pressure better.

Fresh to waste water ratio: Like most back osmosis filters, this system generates four gallons of wastewater for every gallon of water purified. 

Certifications: Aquasana conducts rigorous testing on their products, and this model is certified to NSF/ANSI standards so you can be certain it is effective.

Price: This tap water filter normally runs you $500 to purchase, but it does require drilling into the freshwater piping to install so it is recommended that you have a plumber do it. The good news is that the filter replacement cartridges only cost about $65 each. 


  • Rigorously tested and certified to NSF/ANSI standards to remove 87 contaminants including fluoride
  • 6-stage filtration system with RO
  • The reliable and trustworthy brand you can count on
  • The more affordable price point
  • 0.5 GPM rate of flow
  • Remineralization stage for better taste and alkalinity


  • Needs a plumber to install
  • High wastewater to fresh water ratio

Bottom Line:  Overall, if you’re looking for a top model with 6-stage filtration, RO, and one of the leading brands that you can rely on, then this OPTIMH20 model is a great choice. 

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4. Pelican Pentair 3 Stage

pelican undersink

Next is the PDF-1000VF under-sink filtration system by Pelican Pentair Water. 

Pelican Pentair Water is an established and trustworthy brand, and you can count on them to deliver a system that provides clean and tasty water. 

This system has a 1,000-gallon capacity, doesn’t generate wastewater, and contains a metered flow control.

This Pelican model is a 3-stage filtration system that utilizes both GAC and mechanical filters.

  1. 25-micron mechanical pre-filter (removes sediment and large dissolved particles)
  2. Two catalytic GAC filters (removes chemicals causing bad odors and tastes including chlorine as well as microorganisms)

Overall, we think this is an excellent carbon undersink water filter if you don’t need reverse osmosis.

Main Features & Benefits

Contaminants removed: This system removes 99% of bacteria, cysts, viruses, chlorine, lead, and particulates for clean, filtered water.

Filter replacements and lifespan: The filter cartridges last from 6-12 months on average, the system has a 1,500-gallon capacity and Pelican offers a one-year manufacturer warranty.

Flow rate: With a 1 GPM rate of flow, you can rest assured that you’re not compromising on your tap water pressure to get clean water.

Certifications: This product is IAPMO certified to the NSF/ANSI standards.

Price: The base price of this filter is $185, and the cartridges are $80 to replace in total. The price makes this system a budget-friendly solution.

Keep in mind that you will need a plumber to install this system, however, because it requires fittings that are not standard in most home piping. 


  • Removes 99% of contaminants
  • Rigorously tested and certified to NSF standards
  • Trustworthy and reliable brand
  • Affordable price point
  • 1 GPM flow velocity


  • Additional plumbing fittings needed for most installations
  • Awkward to fit under the counter

Bottom Line:  Overall, if you’re looking for another affordable, quality system, then this model from Pelican is one to consider.

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5. Aquasana AQ5300 3-Stage Max Flow

Aquasana 3 stage

This 3-stage filtration system from Aquasana has all of the features you’d expect from an under-sink tap water filter, at a truly affordable price, from a leading brand, and including a brushed nickel faucet.

Unlike their RO filter, this Aquasana product utilizes a multi-stage carbon filter with Claryum to achieve filtered water.

  1. Activated carbon filter (removes organic chemicals and VOCs like pesticides and some pharmaceuticals)
  2. Catalytic carbon filter (reduces chlorine and chloramines)
  3. Ion-exchange filter (works on lead, mercury, and other heavy metals)
  4. Absolute sub-micron mechanical filter (removes asbestos and microorganism cysts)

The difference between this unit and the other one we featured above is the RO system. 

RO just provides an added level of filtration and removal of harmful contaminants but this 3-stage system is a great option for the homeowner who doesn’t need to remove additional contaminants.

Main Features & Benefits

Contaminants removed: Reduces or removes 77+ harmful contaminants with its 3-stage system. 

Filter Replacements and Lifespan: The filter cartridges are good for 800 gallons of tap water and need to be replaced every six months. The main system itself comes with a one-year warranty and has a 90-day guarantee from the manufacturer. 

Flow rate: Because this model uses a multi-stage carbon filter system instead of a RO filter, the rate of water flow is a moderate 0.5 GPM.

Certifications: This product has been NSF/ANSI certified for multiple standards.

Price: The price of the under sink system itself is $225, and the replacement cartridges are $80. That makes this product a good middle-of-the-road option.


  • 77+ tap water contaminants removed
  • Tool-free filter change
  • Simple installation – good for DIYers
  • 0.5 GPM rate of flow
  • A separate faucet is included with the system
  • NSF certification


  • Some wear items (such as seals and o-rings) will not last as long as competing models

Bottom Line:  This is one of the budget choices we included on our list. Despite its cheap price, this sink filtering system is capable of producing clean and crisp water, like the expensive models.

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6. Waterdrop 3 Stage Black

waterdrop undersink

Next is the Waterdrop 3-stage ultrafiltration under the kitchen sink system. 

Waterdrop’s version of the carbon filter has several advantages including an integrated waterway and an indicator system that lets you know when the filters need to be changed. 

The Waterdrop ultrafiltration system does not require an under-sink electricity supply and produces quality purified water with zero wastewater.

It uses the following stages:

  1. PP Sediment filter (removes large suspended particles like sand, rust, etc)
  2. Ultrafiltration filter (a mechanical filter that blocks particles larger than 0.1 microns)
  3. Carbon block filter (reduces most of the chemicals causing bad odors and tastes as well as heavy metals)

The main difference between this model and the other one featured above is RO filtration. This unit is a standard carbon filter system that will remove most of the main water contaminants in your feed. 

Main Features & Benefits

Contaminants removed: The ultrafiltration membrane has a pore size of 0.01 micron, so combined with the other stages it can filter out most of the water contaminants for pure filtered water.

This kitchen sink filtration system does not remove TDS (total dissolved solids), which means that healthy minerals like calcium, magnesium, potassium, sodium, etc stay in the water. 

Filter lifespan and replacement: The sediment filter lasts 6 months, the carbon block filter lasts 12 months, and the ultrafiltration filter lasts up to 24 months.

It also has a cutting-edge integrated waterway to prevent water leakage, which allows you to replace the filters without cutting off the water supply.

Flow rate: Like most non-RO filters, this model has a water pressure of roughly 0.5 GPM.

Certifications: Unlike the other products, this model has not been certified by the NSF or WQA. 

Price: At $175 to install and $166 to replace the filters yearly, this is another great low-cost solution for your water filtration needs.


  • Low-cost and high-quality system
  • Innovative technology
  • 3-stage quality filtration
  • Sleek good looking design that fits nicely under the sink
  • Easy to install and maintain


  • Not as powerful as their G3 model
  • Does not reduce TDS
  • Smaller capacity than the G3

Bottom Line:  Overall, this system from Waterdrop is an innovative, all-in-one, intelligent purification system that is super cost-effective and easy to install.

7. Ecosoft 3-stage High Capacity


Ecosoft’s 3-stage tankless under-counter water filter was a real surprise for us and snuck into the top 10. 

This gem doesn’t have a big-name brand behind it, but the quality of water it produces certainly earns it a place on this list.

This 3-stage filtration system is made with the following components: 

  1. Sediment filter (filters out large particles and suspended material)
  2. Ecomix filter (reduces ammonium, organic matter, minerals, iron, and manganese)
  3. Carbon block filter (removes organic chemicals and VOCs as well as many heavy metals)

Overall, it’s a good filter for a budget option if you aren’t looking to spend the kind of money one of our top RO-style picks calls for.

Main Features & Benefits

Contaminants removed: This filter removes heavy metals, chlorine, and sediment, and reduces manganese and iron levels too. The Ecosoft filters scale-causing minerals like magnesium and calcium, softening the incoming water as well.

Filter lifespan and replacement: This filter system is a little different in that they recommend their cartridges be replaced every 6 months, and there is a built-in pressure gauge that will give you a heads up when it’s time. 

Flow rate: The flow rate and water pressure are slower than some of the other filters on our list, which is a downside. 

Certifications: This product is not certified by either NSF or WQA.

Price: The price for the system is $120, and while the cartridges need to be replaced every 6 months they are only $20.


  • Affordable setup kit and filters 
  • Faucet included
  • Easy installation
  • Very affordable budget option


  • Lower flow rate

Bottom Line:  Everything you need for installation comes in the box, and fitting is simple enough for most competent people. The low water pressure flow rate is a drawback though.

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8. iSpring RCC7AK


Another good option is the iSpring RCC7AK model

This model has 6-stage filtration with alkaline water remineralization and it is a RO system. 

Many users have reviewed this product, and the overall consensus is that it is one of the top reverse osmosis under sink filtration systems at an affordable price.

We also did a full iSpring filter review if you want more information about the company.

This filter has top-of-the-line filter capacity and reverse osmosis filters. It is made of the following stages: 

  1. 5-stage RO filter (uses standard RO to remove over 99% of contaminants)
  2. Remineralization alkaline water filter (adds electrolytes and healthy minerals back into the water to add a pleasant taste and alkalinity)

For an under-sink filter that also comes with RO and demineralization, this product is a great bang for the buck.

Main Features & Benefits

Contaminants removed: This system removes 99% of total dissolved solids, chemicals, and VOCs including fluoride, asbestos, arsenic, etc. 

Filter lifespan and replacement: The filters should be replaced every 6 months roughly, and both replacement and installation are easy DIY projects. 

Flow rate: At 75 gallons per day, this filter has a water pressure flow rate that is more like you would expect from a RO under sink system. 

Wastewater to pure water ratio: This system produces three gallons of wastewater for every gallon of water purified, which is slightly better than the average for back osmosis filters. 

Certifications: This product has been NSF certified. 

Price: The initial cost for the under sink system is about $300, which is less than you’ll pay for most other RO systems. For a year’s supply of replacement filters, it’s $95. 


  • 6-stage filtration using RO
  • Good customer service
  • Good overall customer feedback
  • Affordable
  • NSF certification


  • Wastes more water than a non-RO option
  • Bulkier and takes up more space under the sink
  • Low flow rate

Bottom Line:  Overall, if you’re looking for a sink reverse osmosis system option this is another good product to consider. 

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9. CuZn UC-200 Under Counter Water Filter


With an average 4.8 star rating from almost 1,500 Amazon reviews, it would be fair to say that the UC-200 is a popular under-sink filter…and 91% of reviews rate it as five stars.

This product incorporates several different filtration components to purify your water:

  1. Microsediment membrane (reduces the amount of smaller suspended particles)
  2. KDF-55 filtration media and catalytic carbon block filters (remove metallic elements, VOCs, organic and inorganic chemicals, bad tastes, and odors)

The best feature of this filter is the 5-year filter life and the high filter capacity 3-stage system it comes with.

It’s easy to install and very cost-effective for someone looking for a standard carbon under sink filter option.

We also reviewed this unit in full detail at our CuZn UC-200 review.

Main Features & Benefits

Contaminant removal: The UC-200 doesn’t actively soften water and is unsuitable for use with well water, but it provides outstanding results when used with municipal water supplies.

The unit inhibits bacterial and mold growth whilst providing excellent filtration of chlorine, pesticides, metallic elements, sediment, algae, and bad tastes and odors.

Filter lifespan and replacement: Connecting directly to your current dedicated faucet, this unit has a filter rated to last for 5 years – that’s a pretty long time. 

Easy to install, the unit doesn’t require the installation of an additional faucet and requires virtually no maintenance. The only downside is the unit’s size, which is quite bulky.

Flow rate: This product’s water pressure flow rate is not available but there are no customer reviews stating that there has been a significant reduction in pressure. 

Certifications: This product has been NSF certified. 

Price: One of the main appeals of this filter is its cost. Its longevity means that you’re not going to pay as much for this system. There’s also a five-year warranty on each filter that ensures its life expectancy.


  • Excellent filtration
  • Very long filter life
  • Responsive customer support


  • Larger than other under-sink water filtration systems
  • Does not reduce TDS or PPM meter readings

Bottom Line:  Overall, you can get great value from this popular filter and still remove most contaminants.

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10. APEC WFS 1000

apec wfs

Last on our list is the APEC WFS 1000 model. This honorable mention is another budget option that offers good filtration at an affordable price.

This under-sink system uses a 3-stage system to filter out impurities similar to many of the other filters on our list.

  1. High-capacity polypropylene sediment (removes suspended particles like dust, sand, and rust)
  2. Carbon block filter (takes out chlorine, bad tastes and odors, VOCs, and other chemicals)
  3. Second carbon block filter (further refinement and filtration of the same contaminants)

Each filter in this system is designed to last around 1 year and the system is simple and easy to use.

Overall, APEC is a solid brand in the water filtration market that competes with our top picks.

Main Features & Benefits

Contaminants removed: It’s guaranteed to remove chemicals, taste, and odors and has a 3 stage filtration system with 2 super-capacity carbon blocks and a super-capacity sediment filter.

Filter longevity and replacement: While this filter system isn’t as durable as some of the others, it does come with a 1-year manufacturer warranty and the cartridges last for roughly a year. 

Flow rate: This model boasts a higher water pressure flow rate than some of the other filters. 

Certifications: This filter has not been NSF or WQA certified. 

Price: For the main system the price is $160, and the replacement cartridges run about $45 per year to change out. 


  • Affordable price
  • Effective filtration
  • Made in the USA


  • Not as effective as our top picks
  • The brand is not as reputable
  • Just ok

Bottom Line:  Overall, this model does not match our top picks, but if you’re looking for an average budget option then it’s worth a look. This product is also made in the USA, it’s earth-friendly and easy to install.

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Under Sink Water Filter Buyer’s Guide


It’s easy to be swept away in a flood of technical jargon and perplexing comparisons when it comes to water treatment.

Our goal is to make these useful systems as simple as possible so that you know what matters and what doesn’t, allowing you to pick the finest under-counter water filter for your needs.

What is an Under Sink Water Filter?

An under-sink water filter is a filter that is installed beneath a sink (usually in the kitchen) and connects to the incoming cold water feed line.

Water passing through the filter is purified and delivered from the dedicated faucet with higher quality and fewer contaminants, tastes, and odors.

These units are usually best for people looking for just drinking water filtration and who aren’t as concerned with having all their home water filtered.

How Do Under Sink Water Filters Work?

Most under-sink filters use a combination of activated carbon block filters and pre-filters to trap sediments and organic materials within the incoming water feed as well as RO membrane filtration. 

Filters or casings can be bacteriostatic or are often given an antimicrobial coating to prevent mold and bacteria growth within the filter.

UV filtration and KDF filters are also often used in under-sink models. 

Learn more about the different types of under sink water filters.

Different Types of Under Sink Water Filters


There are 3 defined types of under-counter water filters:

  1. Conventional
  2. Simple
  3. Reverse Osmosis

The differences between each have been described below.


Conventional under-counter water filters connect to the existing cold water line to the sink and feed a separate faucet (usually included with the filter kit). These systems can be more complicated to fit.


Simple water filters are fitted in line with the cold water feed to your current faucet. This minimizes complications when installing as fewer plumbing changes are required, and it also removes the need to drill through your countertops and fit the additional filtered faucet.

Simple water filtration systems tend to require replacement filters more regularly because they are filtering all water that goes to the faucet. This causes a significant increase in the wear and tear on the filter in a busy home. 

Reverse Osmosis

Reverse Osmosis (RO) filters work differently from other filtration systems.

Most other filters use the incoming water pressure to push feed water through the filtration devices designed to trap sediments, destroy organic particles such as bacteria, and filter out contaminants like pesticides and metallic elements (depending on the model).

RO uses pressure across a semi-permeable membrane to force pure water to one side of the membrane while contaminants remain on the other. This results in purified water which is stored in a tank for use at the faucet, and a brine mixture containing all of the contaminants, which is then flushed away as waste.

The nature of the flushing process means that a significant volume of water is wasted with RO systems, and the need for pre-filters and a storage tank results in a bulkier system needing to be situated below the sink.

Why Use an Under Sink Water Filter?

under sink filter

There are many benefits to using an under-sink water filter in your home:

  • Improves the taste of drinking water
  • Removes contaminants that can cause short-term and long-term illnesses
  • Takes up very little space
  • A very affordable way to improve water quality
  • Saves money on buying bottled water, as well as plastic waste
  • Easy to install without a plumber (depending on the model)

The reality is that water quality is becoming more widely discussed in America, and catastrophes such as those seen in Flint, Michigan have made more and more people aware of potential contaminants within their water feed.

Under sink water filters are a simple, cheap, and reliable way to achieve this.

Under Sink vs Countertop Filters


You may be wondering if you have other options besides an under-sink water filter, and the answer is yes. You can also look at getting a countertop filter, and we’ll take you through the pros and cons of both.

Under Sink Filter Pros and Cons


  • Hidden within cupboard unit
  • Easily accessed for filter changing and maintenance 
  • Provide effective filtration to the dedicated or existing faucet
  • Wide range of models available
  • Cheaper than whole-house filtration systems 
  • Easy to fit


  • Only filters water to one outlet 
  • Can be awkward to install depending on the cupboard size 
  • Can take up space in the cupboard 
  • Leaks can go unnoticed

Countertop Filter Pros and Cons


  • Small 
  • Easy to access for maintenance and filter changes
  • Leaks are obvious as the unit is in full view


  • Slower filtration rate
  • Take up space on the kitchen worktop

How to Install an Under Sink Water Filter


The installation method will vary according to the model of the under-sink water filter that you purchase and you should always follow the manufacturer’s instructions.

However, fitting the units will usually follow the same steps:

  1. Isolate your water feed and switch on the tap until any excess pressure and water have drained.
  2. If your filter has a dedicated faucet, fit this to the countertop by drilling a hole in the desired position and inserting the stem. Secure using the fixings provided.
  3. Fix the filter body below the sink in the kitchen cabinet.
  4. Connect the existing cold water feed to the new filter. If using a simple under-sink filter, this will connect in line to your existing tap. If using a conventional filter, you will need to cut a tee into the cold water feed, then connect one side to the existing faucet pipework and the other side to the new filter.
  5. Connect and tubing and ensure joints are tight.
  6. Close the taps and slowly switch the water back on. 
  7. Reopen the taps to vent any air from the cold water pipes – switch off again once the water runs through normally.
  8. Check all joints for any sign of leaks.
  9. Flush the filter through as directed by the manufacturer, usually for 5-10 minutes
  10. The under-sink water filter is ready to use!

See our complete guide on how to install an under-sink filter & how much it costs.

When Do You Need to Change the Filter Cartridge?

The manufacturer will always include guidelines for the expected cartridge filter life within the product literature however as you get used to using your under-sink water filter you may notice some early warning signs that the filter is coming to the end of its life.

1. Flow rate is reduced 

This can be a sign that the tiny pores within carbon filters are becoming clogged up with residue.

2. Changes to Taste 

As a filter becomes clogged with contaminants removed from the water feed it will begin to allow some particles through that would otherwise have been filtered – these will affect the taste of the water at the faucet.

3. Low Flow Rate

This can be a sign that the tiny pores within carbon filters are becoming blocked as they reach capacity or that the RO membrane is becoming more permeable. Check that all valves are properly open but if the flow rate to other outlets is unaffected, it is time to buy a new cartridge. 

See our guide on how often you should change your under-sink filters and how to change them.

Under Sink Water Filtration System FAQs


What Type of Under Sink Water Filter is Best?

There is no one best filter because it depends on your water quality and home needs. If you’re looking for the highest filtration capability go with a reverse osmosis under sink model.

If you just need pure filtered water with the normal contaminants removed check out the carbon under-sink models.

Should I Get a Reverse Osmosis or Standard Model?

If you want to remove the most contaminants under counter reverse osmosis systems will be best.

If you just want a solid water filter at a reasonable cost, check out the sediment and carbon filters that fit under the sink.

Will I Need an Electricity Source to Power The Filter?

No, an electricity source is usually not needed since these filters hook up to your main cold water supply line.

Can you DIY your own Under Sink Water Filter?

Sure, if you have the handyman skills to DIY your own under sink filter go ahead and give it a shot but it’s much easier and more cost-effective to purchase one.

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Stephanie Nielsen
Stephanie worked as a department supervisor of kitchen, bath, and appliances at Home Depot, and water filters were part of the inventory she was responsible for assisting clients with so she learned the ins and outs of matching the right filtration device to homeowner’s needs. She also worked closely with Culligan water to educate customers about whole-home water treatment and softener systems.

Learn More About The Water Tech Editorial Team