An In-Depth Comparison Of The Best Under Sink Water Filters

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Water filters are a necessary addition to any home, and under sink water filters are some of the bests on the market. In this post, we will compare three of the best under sink water filters on the market to help you decide which one is right for you.  

We will discuss the features and benefits of each filter, as well as when it would be most appropriate to use it. By the end of this post, you will have all the information you need to make an informed decision about which water filter is right for your home. 

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What Is Under Sink Water Filter?

There are at least four different types of under-sink filters: 

Activated Carbon Filter

Carbon filters use activated carbon to remove contaminants from the water supply. They consist of a large carbon block with smaller carbon grains and produce a large amount of wastewater as a by-product. Whole house filtration systems can have an under-sink filter added for convenience, but the more economical reverse osmosis systems are a better alternative. 

Reverse Osmosis

Reverse osmosis filters out contaminants, using pressure to push the water through a membrane which blocks things such as lead and arsenic that affect health. It is used to produce less wastewater as a by-product. There are three types of membranes, each with advantages and disadvantages. 


A distiller uses heat to boil water into steam, leaving contaminants behind. The steam is condensed back to water, resulting in purer water than the original supply (distillation does not remove volatile organic compounds). An advantage is that it can provide distilled water for small applications. A disadvantage is that it only works on a continuous supply of high-quality water, not well water or standing tap water. 

Ultraviolet (UV)

Ultraviolet (UV) filters use ultraviolet (UV) light to deactivate bacteria in the water supply. There are two types: germicidal UV, which is commonly used for water disinfection, and the low-pressure mercury vapor lamp. These lamps are also very good at removing contaminants such as VOCs (volatile organic compounds) from water supply. The small size of UV light causes little waste-water production, but since it is an electrical unit, ultraviolet filters must be used with care to avoid electrocution. 

Under sink water filter advantages

Even though we live in a highly modernized society it is still ever so important to make sure you are drinking clean and healthy water.  

There are many kinds of water filters to choose from but the best option for those who do not want to constantly change filter cartridges would be under sink water filters. 

Under Sink Water Filters is a company that specializes in making the best under sink water filters. They have many different installation options, and they also provide you with customer service so there is no need to worry about installation or lack of knowledge about your filter system.  

Here are some of the most popular and best benefits and features of an under-sink water filter: 

  • No Wasted Water 
  • Get Rid of Bottled Water and Save the Environment 
  • Under Sink Installation is Easy 
  • Variable Filtration Options for Better Health 
  • Convenient when Traveling 

Many people living in highly populated areas do not have access to clean and healthy drinking water.  

This can cause problems regarding health and energy levels. When you are drinking fresh, clean, filtered water then you will be giving your body the nutrients that it needs to stay healthy without spending too much money on bottled water or constantly worrying about filtering the tap water yourself. 

10 Best Under Sink Water Filters Reviews

If you purchase an under-sink water filter, you might as well buy the most effective one. But with so many available options and sales pitches, how can you determine which is the best? Certain products provide superior filtered water, whether you’re searching for a reverse osmosis (RO) system or a carbon-block system. 

To ensure that you can find the best under-sink water filtration system for your home, I have spent the last four weeks evaluating, comparing, and ranking the following filtration systems. 

Here’s what I discovered. 

1. Best Overall: iSpring RCC7P-AK 6-Stage Reverse Osmosis System Under Sink Water Filter

This iSpring reverse osmosis system eliminates up to 99 percent of over 1,000 contaminants found in tap water, including lead, arsenic, chlorine, fluoride, and asbestos. Its six stages of filtration include sediment and carbon filters to remove large contaminants and protect the reverse osmosis membrane from chlorine and chloramines. 

The reverse osmosis filter eliminates contaminants as small as 0.0001 microns, allowing only water molecules to pass. An alkaline remineralization filter restores healthy minerals lost during the filtration process. The final filtration stage polishes the water before it is delivered to the brass faucet, which features a sleek, brushed nickel design. 

A ratio of 1 gallon of filtered water to 1.5 gallons of wastewater is achieved through an electric pump to increase water pressure. Filters must be replaced every six to twelve months. The user can install it with the company’s written and video guides. Those who encounter problems or have questions that aren’t addressed in the manuals can contact a live phone support agent. 

Key Features 
  • 3 Pre-filters: PP sediment filter. Carbon KDF (GAC) filter. Carbon block (CTO) filter. They remove large contaminants and protect the RO membrane from chemicals like chlorine and chloramines. 
  • The heart of the system is the Reverse Osmosis (RO) filter that removes contaminants down to 0.0001 microns – so small that only water molecules can squeeze through but virtually nothing else. 
  • Fine GAC filter provides final polishing before the purified water is delivered to the faucet. 
  • An Alkaline Remineralization filter restores healthy minerals and a natural alkaline balance, while also producing a more natural taste. 
  • The result is great-tasting bottled-water quality. 
  • Capable of removing 1,000 contaminants through 6 filtration stages
  • Electric pump aids water pressure
  • Brass faucet and reverse osmosis filter included
  • Easy to install; written and video instructions included
  • Expensive compared to other systems

2. Runner Up: Express Water RO5DX Under Sink Water Filter

Express Water RO5DX Reverse Osmosis Filtration NSF Certified 5 Stage RO System with Faucet and Tank – Under Sink Water Plus 4 Filters – 50 GPD, 14 x 15 x 5, White


This reverse osmosis system with five stages of filtration is an excellent option for any home that uses municipal water, as it comes with an assortment of simple-to-install fittings and upgrades, such as ultraviolet, alkaline, and deionization filters. 

Before reaching the RO membrane, which removes the smallest contaminants, the water in this system passes through a sediment filter and two carbon filters. The final stage consists of a third carbon filter to remove any lingering toxins. 

The system is inexpensive and includes four replacement filters that must be replaced twice yearly. This system’s lack of a pump results in approximately 1 to 3 gallons of wastewater per day. 

Key Features 
  • Reverse Osmosis Water Filter 
  • Water Purification System 
  • Under Sink Water Filter 
  • Leak Detection 
  • Customizable RO Water Filter System 
  • Budget-friendly system
  • 5-stage filtration; ultraviolet, alkaline, and deionization filters
  • 4 replacement filters included
  • Slightly large; takes up more space than other systems

3. Best under-sink filter for your home: Aquasana 3-Stage Max Flow Claryum Under Sink Water Filter System

Aquasana 3-Stage Max Flow Claryum Under Sink Water Filter System – Kitchen Counter Claryum Filtration – Filters 99% Of Chlorine – Brushed Nickel Faucet – AQ-5300+.55 , White


Aquasana has established itself as an industry leader in water filtration over the past 25 years. Its innovative multi-filtration technology, NSF-certified to remove 77 contaminants, including heavy metals, pesticides, pharmaceuticals, and water treatment disinfectants, earns high marks from our engineers.  

It is also one of the few filters certified to remove PFAS, which is a significant reason why Birnur Aral, Ph.D., director of the GH Health, Beauty, Environment, and Sustainability Lab, installed this Aquasana in her own home. As she attests, the device performs all this filtering without premature clogging or a decrease in flow rate, despite her using it for cooking, filling the coffee machine each morning, and, of course, hydrating throughout the day! 

Key Features 
  • Instantly Transform Ordinary Tap Water Into Clean, Extraordinary Water 
  • High Flow Rate 
  • Cost Efficient & Long Lasting 
  • Easiest Filter Replacement 
  • Top-Grade Components 
  • Superb filtration, including PFAS
  • Easy to install
  • Resists clogging
  • Takes up more cabinet space than some

4. Best Value Under-sink Water Filter: Culligan US-EZ-4 EZ-Change Sink Drinking Water Filtration System

Culligan US-EZ-4 EZ-Change Sink Drinking Water Filtration System with Dedicated Faucet and Premium Filter, US-EZ-4, Chrome


Even though we have not tested this system, Culligan is a well-respected brand in the water filtration industry with a solid track record from previous Good Housekeeping reviews. Additionally, replacement filters are relatively inexpensive.  

It is certified to remove various contaminants, including lead, mercury, and cysts, and it reduces chlorine taste and odor. However, its granular activated carbon filtration is not as robust as that of other leading products: For instance, the filter is not certified following NSF standard 401, which covers pharmaceuticals, herbicides, and pesticides. The EZ-Change can filter 500 gallons of water before it must be replaced. This is commendable for a low-cost filter but less than the 700 to 800 gallons we observe with other models. 

Key Features 
  • Provide your family with visibly clean, great-tasting water for drinking, cooking and more 
  • Features: Reduces particulates class 1, chloride, cyst, chloroform, MTBE, mercury, lead, turbidity, per fluorinated chemicals; 0.5 GPM flow rate; Includes 1 twist-on/off filter cartridge replacement, tubing, dedicated faucet, and installation hardware 
  • Compatibility: Culligan US-EZ-4 cartridges 
  • Filter life: Up to 6 months or 500 gallons, depending on usage and water conditions 
  • Certification: Tested and certified by IAPMO to NSF/ANSI Standard 42 for the aesthetic reduction of Chlorine Taste and Odor, Chloramines and Nominal Particulate Class 1. Standard 53 for the reduction of Cysts, Mercury, lead, VOC, MTBE and Turbidity 
  • Excellent price
  • Simple installation and filter replacement
  • Not certified to remove PFASs

5. Best Compact Under-sink Water Filter: Multipure Aquaversa Model MP750 Drinking Water System

Multipure Aquaversa Model MP750 Drinking Water System With Below Sink Kit and Chrome Faucet

If kitchen cabinet storage space is limited, the compact design of MultiPure’s under-sink water filter will be appreciated. In field tests, our specialists observed that the 5.8″ x 5.8″ x 8.5″ housing can be mounted to a cabinet wall, leaving ample space under the sink for additional items. Initial installation was straightforward, and filter replacement was also simple.  

Certified to NSF standards 42, 53, and 401, the solid carbon block filter effectively captures a wide variety of contaminants. Our tester reported that, if the filter is replaced annually, the flow rate remains strong and consistent even during the summer, when household water consumption is at its highest. 

Key Features 
  • Widest Range of Contaminant Reduction 
  • Cost-Effective 
  • Peace of Mind 
  • Protection   
  • Taste/ Convenience 
  • Compact design
  • Excellent filtration
  • Resists clogging
  • Pricey

6. Best Reverse Osmosis Under-sink Water Filter: Waterdrop G3 Reverse Osmosis System

Waterdrop G3 Reverse Osmosis System, Tankless RO Water Filtration Systems, Under Sink, NSF Certified, TDS Reduction, 400 GPD, Smart LED Faucet, UL Listed Power, USA Tech


Although the Waterdrop under-sink water filter is not inexpensive, it is significantly less expensive than other reverse osmosis (RO) systems. According to the manufacturer, the tankless design conserves space and increases water efficiency.  

Although we have not tested the unit, previous reports on RO technology confirm its effectiveness at removing contaminants. The Waterdrop is NSF 58 certified, one of the most stringent standards, so that it can resist heavy metals, pharmaceuticals, and PFAS.  

Our engineers appreciate the device’s intelligent design, including a filter light indicator on the faucet and a monitoring panel that displays the amount of TDS, or total dissolved solids, removed from the water. The Waterdrop is not intended for well water, unlike the other filters in this roundup, as the presence of large particles can cause clogging. 

Key Features 
  • NSF 58 & 372 certified 
  • Outstanding filtration performance 
  • Smart display faucet 
  • 400 GPD&1:1 pure to drain ratio 
  • Integrated water way design 
  • Automatic flushing 
  • Exceptional filtering
  • Compact, tankless design
  • Smart controls
  • Pricey
  • Not suited to well water

7. Best Budget: Waterdrop 15UA Under Sink Water Filter System

Waterdrop RF15 Replacement Filter Cartridge For 15UA/15UB/15UC Under Sink Water Filter, Reduces Lead, Chlorine, Bad Taste & Odor, NSF/ANSI 42 Certified, 19K Gallons High Capacity


Water filtration does not have to cost an arm and a leg, nor does the installation of a filtration system have to consume an entire weekend. This inexpensive under-sink water filter system from Waterdrop can be installed in three minutes, making it simple to obtain clean tap water. 

 This model is also an excellent option for consumers who lack the cabinet space to accommodate a more extensive filtration system. The small attachment connects directly to the cold-water line. It dispenses carbon-filtered water from the main faucet, reducing odor and contaminants such as chlorine, sediment, rust, and other heavy metals. Although it does not remove as many pollutants as a RO system, it does preserve healthy minerals such as calcium, potassium, and magnesium. 

Waterdrop’s push-to-connect fittings and twist-and-lock filter-changing system make for a simple installation. Each filter has a maximum service life of 24 months or 16,000 gallons for straightforward maintenance. 

Key Features 
  • Ultra-Long Service Life 
  • Innovative Multistage Filtration 
  • WQA Certified Filter 
  • Easy Installation 
  • Fast Flow Rate & Multiple Uses 
  • Affordable system
  • Removes heavy metals with 3-stage carbon filtration
  • Filters last for up to 2 years
  • 3-minute installation process
  • Not suitable for well water

8. Best Faucet Options: Aquasana 2-Stage Under Sink Water Filter System

Consider this model from Aquasana if you’re looking for a replacement faucet for your under-sink water filter. The system has two stages of filtration and can remove up to 99 percent of 77 contaminants, including lead and mercury, and 97 percent of chlorine and chloramines. It is available in three stylish finishes to complement a variety of kitchen decors. The filters are designed to be environmentally friendly with minimal disposable plastic components. 

Since the system does not employ a RO membrane, there is no water waste, and the filtration process preserves healthy minerals. It has a filter capacity of approximately 600 gallons, lasting up to six months. With the aid of a comprehensive manual, the owner can perform the installation. 

Key Features 
  • Removes up to 99% of 77 contaminants including lead, mercury, asbestos, herbicides, pesticides, pharmaceuticals, and more 
  • Nothing added and zero waste – no water is wasted, and no harmful contaminants are added to your water during filtration 
  • Only 10 cents per gallon – 12 times the capacity of the leading gravity pitcher. Healthy, clean water for less 
  • Retains the healthy minerals – Claryum filtration keeps calcium, potassium, and magnesium for the healthiest drinking water 
  • Stylish all metal faucet included in the finish of your choice to match your kitchen decor – 100% lead free 
  • Includes first set of filters and all parts required for DIY installation – no plumber required 
  • Full system NSF certified to standards 42, 53, 401 +P473 – will not leach contaminants back into your water 
  • Capable of filtering 77 contaminants with a 2-stage filtration system
  • Environmentally friendly filters
  • Water-saving design
  • Includes faucet; choice between 3 finishes
  • Similar sets come with more options for faucet finish

9. Best For Alkaline Water: APEC Water Systems ROES-PH75 Essence Series

This carbon-filter model from CuZn is in a class by itself for those searching for a long-term water filtration solution. Unlike most under-sink filters, which typically last between six months and two years, this model has a five-year lifespan. The capacity of this filter to purify municipal water is up to 50,000 gallons. 

Its three-stage filtration process creates a bacteriostatic environment within the system that inhibits the growth of mold and bacteria, extending its lifespan. This, combined with a sediment and carbon filter, effectively removes chlorine, heavy metals, and other contaminants. 

However, the filter is still more compact than those with an additional tank. It should not be used in well-water households. Additionally, it features a rapid flow rate and zero water waste. 

Key Features 
  • Safe US Made Alkaline Filter 
  • Super Efficient APEC Carbon Blocks 
  • Superb Taste & Water Purity 
  • Easy Installation and Maintenance 
  • 2 year extended manufacturer warranty 
  • 3-stage sediment and carbon filtration
  • Filters 1,000+ contaminants including heavy metals and chlorine
  • Water-saving design
  • Long lifespan (5 years)
  • Larger than comparable systems; less suitable for small spaces
  • Does not filter well water

10. Best For Well Water: Home Master TMHP HydroPerfection Undersink Water Filter System

Some prefer alkaline water due to its flavor and purported health benefits, whereas plain water is satisfactory for most individuals. Due to a mineral cartridge that adds high-purity calcium carbonate back into the filtered water, alkaline water drinkers can now enjoy this higher pH beverage straight from the tap with this APEC Water Systems filter. 

In terms of filtration, double carbon blocks and a RO membrane eliminate 99 percent of over a thousand contaminants, such as chlorine, fluoride, arsenic, lead, and heavy metals. The system’s certification by the Water Quality Association (WQA), which ensures the quality of water filtration products, makes it a dependable option. 

A faucet in brushed nickel is included with the filter. Consider the water waste associated with this filter, as it has a ratio of 1 gallon of filtered water to 3 gallons of wastewater, which is slightly above average. Those who opt for do-it-yourself installation can access videos and a manual. 

Key Features 
  • Five-year limited warranty 
  • Modular Design 
  • Faster Flow 
  • Iron KDF85 media in the prefilter 
  • EPA approved UV light Sterilization 
  • Artesian Mineral Water on Tap – Patented “Full Contact” Technology 
  • Non-electric permeate pump – improved efficiency and reduced TDS Creep 
  • Double carbon and ultraviolet filtration system removes 1,000+ contaminants
  • Adds calcium carbonate and balances water pH
  • Faucet included
  • Easy to install
  • Wastes water while filtering (1 gallon filtered to 3 gallon waste ratio)
  • Slightly large; may not be suitable for small under sink spaces

Factors To Consider When Choosing Under Sink Water Filter

When it comes to choosing which sink water filter is best for you, there are several factors to consider. What are your specific needs? How big is your family? Do you have pets that drink water as well? These are just some basic considerations to help determine which type of system would be best for you. 

Filter Capacity 

The first thing homeowners should consider before purchasing an under-sink water filter is the number of people who will be using purified drinking water.  

The average person needs two gallons of filtered water per day, according to the Water Quality Association (WQA).  

When choosing a system, keep in mind that some filters work faster than others; if more people are in your household, opt for a filter system that can produce enough filtered water in a shorter amount of time.  

Type of Water Used 

It is important to use the same type of water throughout the entire home when installing under sink water filters because different types of water require different filtration systems and purification techniques.  

Hard and soft water need to be filtered in different ways because the minerals in each water cause them to flow through the plumbing differently. Hard water is difficult to remove due to its higher mineral content, but it can usually be treated with a system that uses sodium or potassium ions.  

Soft water contains very low levels of calcium and magnesium minerals, so it does not require ionization treatment. The type of under sink water filter you need depends on the quality of water used in your home. 

Space Available 

The size and shape of an under-sink water filter will determine how it is installed, so homeowners should measure the space available underneath their countertops before purchasing a system.  

Some filters can filter large amounts of water at once, while others are smaller and need to be replaced more frequently. There are even some under sink water filters that can hold up to two different kinds of water at once. This feature is beneficial for homeowners who want filtered drinking water but also use well water on their lawns or gardens. 

Ease of Installation 

When considering which filter system to purchase, homeowners should consider the ease of installation. S 

ome under sink water filters are simple to install and connect to existing plumbing with regular household tools, while others require professional plumbers to connect the filter correctly.  

If you do not want to hire a plumber or if you simply need something for your guest bathroom or outdoor kitchen, find an under-sink water filter that is easy to install. 

Filter Change Frequency 

Just like any other home appliance, under sink water filters have a lifespan and must be replaced when they are spent.  

The frequency in which you change a filter will depend on how much household members use the filtered drinking water and the mineral content of your tap water. 

 According to the WQA, most filters need to be changed every six months to one year. Sometimes an under-sink water filter needs replacing without any indicators of malfunction.  

Because some systems last longer than others, it is important to monitor their performance and efficiency by checking for leaks or other malfunctions that might indicate the unit needs replacement. 

FAQs About Under Sink Water Filter

A water filter removes impurities from tap water using a variety of methods, including ion-exchange, adsorption, and activated carbon absorption. 

Under sink water filtration has the advantage of having an easy-to-clean filter that is easily accessible for most people. Filters can be installed under either mounted or drop-in sinks. Drop-in filters are usually used when countertop space is not available, but mounted sink filters may look better with a specific style of kitchen faucet. 

Under sink water filters change the standard filters every 6 months because of hard water. They need to be checked more often if their water is very hard (i.e., 175 ppm). Softer waters may only require changes once a year, but this should be done according to the manufacturer’s specifications. 

Under-sink water filters can be moved from one sink to another, making them more versatile than other types of countertop systems. Systems with easy-connect hoses make it possible for two or more separate sinks in a household to have filtered water. 

Some people do not like the look of a filter that is connected to a faucet or a hose, and others complain that water pressure may be lower if the filter is attached to the kitchen sink’s supply line. Water flow from an under-sink filter is slower than that of a system connected to the main water supply. 

Most under-sink filters do not have any special filtration technology that is designed to remove or reduce fluoride levels in drinking water, but some are now available with activated carbon. These filters may reduce up to 40% of the fluoride present in your tap water. 

Under-sink systems can be categorized as: 

  1. Reverse osmosis (RO). RO water filters produce highly purified and nutrient-void H2O. Reverse osmosis systems have a high starting price but create water that is clear and odorless. Since they use a membrane as a filter, these filters also tend to be the most challenging to clean.
  2. Activated carbon (AC). AC filters can remove chlorine from your tap water and improve its taste and smell. These units, however, are not designed to purify water; they simply work as small water softeners for impurities that affect the taste and smell of the water.
  3. Enhanced filtration (EF). EF filters can also reduce chlorine from water, but may use activated carbon treatment, ion exchange technology, or a combination of these methods to remove impurities. Although these units may not produce as clear or odorless water as RO units, they are usually less expensive than comparable RO systems.
  4. Distillers. Good for producing pure distilled water, but does not reduce heavy metals, chemicals, or bacteria like an under-sink water filter would. Distillation is more of a purification process, not an oxidation or chemical reduction process.
  5. Ultraviolet light (UV). UV water filters are often used in conjunction with other types of under-sink units to kill bacteria in the filtered tap water. They are known largely for their ability to remove algae and parasites from filtered water, but they may also reduce chlorine and improve the taste of tap water.
  6. Iron removal filters. A good under-sink filter can remove up to 70 percent of the iron in filtered water, but these units are not effective for removing fluoride or other heavy metals. 

Under sink systems may be more convenient because they can be moved from sink to sink, but countertop water filters may be less expensive, and the filters are easier to replace. 

If you have basic plumbing skills and know how to shut off the main water supply in your home, you may be able to install an under-sink water filter yourself. Otherwise, ask a plumber or find out if installation costs are included in the price of the system. 

Most brands recommend that their filters be replaced at least once every six months or after about 500 gallons of filtered water have been used. 

Yes, replacement filters vary in cost and can be purchased at a home improvement store. For instance, a filter from the Big Berkey system costs about $50 while a replacement for a basic faucet-mounted filter may only cost $25. 

Yes, these filters are typically easy to install with no tools required. However, once they are attached, you cannot move them from sink to sink like some under-sink filters can be moved. For example, you might have one filter for your kitchen sink and another filter installed on the bathroom basin. 

Solid carbon block filters are made from granulated active carbon, which is molded while in a highly compacted state, producing micro-pores so small that they cannot permit the passage of contaminants. They are the most effective filtration systems for providing safe drinking water. 

Carbon block filters are designed to remove impurities at the molecular level while solid carbon filters will absorb other chemicals that affect taste, color, or odor. Carbon blocks can also reduce heavy metal contaminants like lead and mercury. 

Reverse osmosis (RO) systems force water through a special membrane which acts like a filter trapping dissolved particles, bacteria and viruses while passing on the clean water to the faucet. RO filters are good for treating large quantities of impure or contaminated water, but they also waste more water than other types of filters. 

RO systems can be installed under the sink or near to where you need them like on the countertop, and they may come with a storage tank for easier dispensing of filtered water. Systems that are installed under the sink may contain between one and four filters to remove different contaminants like arsenic, fluoride, lead, or chlorine. RO systems will normally require regular maintenance. 


The best under sink water filter will be the one that meets your needs. We hope this article has given you some insight into how to choose a model and we encourage you to keep reading about these filters, as well as check out our buyer’s guide for more information on what features are important when choosing an under-the-sink water filter.  

If you need help finding the right option for your home or office, please contact us! Our team of experts would love to work with you and produce a plan that fits your budget and satisfies all your wants and needs. 

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