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under sink water filter

If the water from your faucet or refrigerator tastes or smells bad and you're concerned it's quality, then an under-sink water filter may be your best water treatment solution. With so many under-sink filter options, it's hard to know which is right for you. We've recommended five best under-sink water filters based on their efficiency, reduction capabilities, and convenience to help narrow your selection. Our under-sink filter buyer's guide will help you find the best kitchen water filter for your home or RV. 

What is an under-sink water filter?

An under-sink water filter is point-of-use (POU), which means it's installed right where you need access to clean water. They filter water directly at your faucet or through your refrigerator for clean drinking water. Under-sink filters are in-line filters that connect right on your waterline. Water passes through the filter on the way to your faucet. Some under-sink filters dispense water through an additional dedicated faucet. Water pitcher or countertop filters are alternatives to an under-sink installation, but under-sink filters are preferred for their convenience and ease of maintenance. 

Under-sink water filters are one of the most popular water treatment choices for homeowners. For many people, whole house filters are not feasible or necessary. Water may be suitable for laundry or showers, but that doesn't mean you'll want to drink it. Even if your water comes from a municipal plant, it may still collect contaminants on the way to your faucet. Some contaminants are dangerous, while others just ruin the taste or smell of water. An under-sink water filter is your best option for optimal water quality in drinking water, foods, and beverages. 

The Best Under-Sink Water Filters

How to choose an under-sink water filter

As you search for an under-sink water filter, the task may seem daunting. Under-sink water filters come in a variety of filtration options at a range of prices. This list will help you discover the perfect drinking water filter for your needs. 

1. Know what needs filtering out of your water.

The type of under-sink filter best suited for your home depends on what contaminants or particles are in the water and need removing. If you're concerned about chlorine taste, then a simple carbon filter can solve your problem. If you want to remove dissolved particles, like sodium from a water softener, then you may need more complex filtration like reverse osmosis (RO). If you're unsure about the quality of your water, conduct a home water test or request a report from your city treatment plant. 

2. Consider ease of installation.

Some under-sink filters are easier to install than others. Many in-line water filters only require a simple connection with an adapter. Other installations, like under-sink RO systems or UV systems, are more involved. Reverse osmosis systems need a drain line connection for reject water, and UV systems require an electrical connection. All under-sink systems can be installed without the aid of a plumber if you're handy with tools and follow the instructions, but you may need help with more complex installations. 

Most under-sink water filters require a faucet connection. Some filters connect directly to your primary faucet or soap dispenser, but others need an additional dedicated faucet. Installing the dedicated faucet is the most difficult part of the process, especially if you must drill a hole in your countertop. You may want assistance if you have granite countertops. 

A more complicated installation, however, may be worth the time and investment to solve your drinking water problem. For example, if your water contains harmful bacteria, then UV disinfection is the best solution.

3. Consider the maintenance required.

Think about the filters' or filter membrane's capacity. How long will those filters last? Most water filters need replacing once a year, and membranes last two to three years. Your water quality could influence the lifespan of the filter. If water contains large amounts of dirt and debris, a filter may reach its maximum capacity sooner. So you should replace the filter if it clogs, no matter how long it's been installed. 

How long do under-sink water filter systems last? 15- 20 years with proper maintenance. Manufacturers recommend that the sumps or body of filter housings (if required) be replaced every 10 years to avoid cracking.

4. Know the cost of filter replacements.

Under-sink filters are less expensive than whole house water filtration, but keep in mind that installing an under-sink filter is not a one-and-done. Effective filtration year after year depends on you. It's important to schedule and budget for the cost of filter replacements to keep your drinking water safe. 

 Filter Filtration Type Ease of Installation Cost of Maintenance Flow Rate Filter Replacement Price
RO- 4300RX Reverse osmosis (RO) Involved $133- 187 1 gpm Annual (membrane 2-3 years) $319.99
ADC RV Carbon Simple $37 0.5 gpm Annual $174.99
DWS-UV Germicidal UV light Involved $100 1 gpm Annual $519.00
K-NPQ1 Carbon Simple $25 0.5 gpm Annual $68.99
TL3 Ultrafiltration Simple $130 1 gpm Annual (membrane every 2 years) $169.99


Under-Sink Water Filter Product Reviews

Neo-Pure RO- 4300RX- DLX - Best Reverse Osmosis Under-Sink Filter

Advantages

  • Alkaline water
  • Pharmacy-trusted
  • Permeate pump 
  • Dual purpose prefilter

Disadvantages

  • Does not contain quick-change filter cartridges

Contaminants reduced

  • Sediment
  • Bad tastes and odors
  • Chlorine
  • Dissolved inorganic contaminants
  • Chemicals

Why the RO-4300 is the best under-sink reverse osmosis filter

All reverse osmosis systems use the same technology-- carbon prefilters, sediment filters, and membranes. The Neo-Pure deluxe under-sink RO, however, has three features that distinguish it from other systems:

The permeate pump

A permeate pump makes a significant difference in the efficiency of a reverse osmosis system. Many people think of RO systems as energy-squanderers because of the significant amount of water sent to the drain during the reverse osmosis process. Installing a permeate pump, however, makes the RO system more efficient. The pump decreases the amount of water to the drain by 85%, and every drop of water passes through the membrane filter. Since many under-sink reverse osmosis systems are compatible with a permeate pump, the Neo-Pure RO deserves the award for most eco-friendly under-sink RO.

Learn more about the benefits of a permeate pump and how to install it.

The alkaline water filter

People shy away from reverse osmosis systems because they do such a great job filtering that they strip all mineral content from water. While we receive most essential minerals through food, some prefer the flavor of mineral water or want to retain minerals to enhance coffee flavor and aroma. As water passes through the alkaline filter of the Neo-Pure RO, it's remineralized. 

Pharmacy-trusted

Pharmacies, including Walmart and Walgreens, use Neo-Pure reverse osmosis systems to reconstitute medicine. The RO 4300 brings the same level of water quality trusted to fill prescriptions to your tap. 

Maintenance on this under-sink RO system is more difficult since the filters aren't quick-change. But this also means that the filters don't require plastic housings, which makes them cheaper to replace. 

How often should you replace the RO filters? Once a year.

How often should you replace the RO membrane? Every 2-3 years.

Stage 1: Carbon/ sediment prefilter

Stage 2: RO membrane

Stage 3: Carbon/ sediment prefilter

Stage 4: Alkaline water filter

Stage 5: Postfilter

Everpure ADC RV - Best Under-Sink Water Filter for RVs

Advantages

  • Treated with bacteriostat to prevent bacterial growth in filter media
  • Quick-change filter cartridges

Disadvantages

  • No scale control for locations with hard water

Contaminants removed

  • Chlorine
  • Tastes and odors
  • Asbestos
  • Cysts

Why the Everpure ADC is the best under-sink RV filter

The Everpure ADC filter is designed with RVs in mind. Installing this filter under the sink in your camper means you don't have to sacrifice delicious coffee, tea, and other beverages on your adventures. You can know for sure that the water is clean, making your RV even more like a home away from home. Here's what makes the Everpure ADC a great RV filter:

Bacteriostat media

Few under-sink RV filters can claim to fight cysts and asbestos, but the media in an ADC filter contains bacteriostat to prevent bacterial growth. Antibacterial media is especially important when your camper sits parked without the air running for extended periods. The moisture aids bacterial growth in the filter. When you're camping, there's no telling where the water comes from or what's in it. Even if campsite water is treated, it likely contains chemicals from disinfectants. The ACD under-sink RV filter leaves no cause for worry about nasty water at campgrounds. 

Convenience

Most other RV filters require a connection outside the RV with garden hose adapters, but the ADC can be plumbed directly under your sink. The cartridge is also quick-change for simple filter replacements on the go. 

This Everpure RV filter provides excellent capacity for its variety of benefits, but it doesn't have a fast water flow rate. The ADC is a pass-through carbon filter. Carbon relies on enough contact time with water to remove contaminants effectively. 

How often should you replace the RV filter? Once a year or once an RV season. Make sure you replace the filter at the beginning of each season. Don't reuse the filter after it's been sitting unused for a while. 

Viqua DWS-UV - Best UV Under-Sink Water Filter

Advantages

  • Additional sediment filtration

Disadvantages

  • Heats water up

Contaminants removed

  • Bacteria
  • Heavy Metals
  • Cysts
  • Sediment

Why the Viqua DWS is the best under-sink UV system

Ultraviolet water treatment is your best option when your water contains bacteria or when you want to protect it from pathogens. UV light deactivates the DNA of living organisms, so they can no longer disinfect your water and infect your body. The Viqua DWS is unique because it not only treats water for bacteria, but it includes filtration to remove other types of contaminants. 

Disinfection plus filtration

The Viqua DWS disinfects water with UV light and includes sediment and carbon filters, which means it reduces more contaminants than other UV systems. This UV removes dirt and debris with a sediment filter and bad tastes, odors, and chlorine with the carbon filter. The additional filters make the UV system more efficient. Filtration happens prior to the UV disinfection so particles don't weaken the effect of the UV rays on water. 

Keep in mind when UV lamps disinfect, the water heats up. This makes your drinking water a little warmer, especially when the faucet hasn't been turned on in a while, giving water longer exposure to the UV light. 

How often should you replace the UV lamp and UV filters? Once a year. 

How often should you replace the quartz sleeve? Every two years upon inspection. 

Neo-Pure K-NPQ1 - Best Under-Sink Water Filter for Refrigerator

Advantages

  • Scale control
  • Lead reduction
  • Quick-change filter cartridges

Disadvantages

  • None! It's a great filter.

Contaminants reduced

  • Cysts
  • Lead 
  • Chlorine
  • Tastes and odors
  • Scale
  • Sediment

Why the Neo-Pure K-NPQ1 is the best under-sink refrigerator filter

The Neo-Pure K-NPQ1 is a simple but powerful filter that cleans water for your water cooler, sink, refrigerator, and ice maker. Any of the under-sink water filters recommended can connect from your sink to your refrigerator, but the Neo-Pure K-NPQ1 works best with appliances. Here's why:

Scale control

This Neo-Pure filter system would be right for you want to protect your appliances from the effects of hard water. Hard water contains excessive calcium and magnesium that leaves their dissolved state in water. They build up in your refrigerator, ice machine, or water cooler. The scale inhibitor holds these minerals in their solution to prevent them from damaging your kitchen appliances. 

Removes lead

This Neo-Pure under-sink filter uses a special blend of carbon rated to reduce lead. On its own, carbon can't remove lead or cysts, but the K-NPQ1 filter has microns small enough to block these dangerous contaminants from passing through.

Like the ADC RV filter, the KNPQ-1 is a pass-through filter that requires plenty of contact time with carbon, which causes a lower flow rate.

How often should you replace the under-sink fridge filter? Once a year or  every 1,250 gallons, whichever comes first.

Neo-Pure TL3 - Best Ultrafiltration Under-Sink Water Filter

Advantages

  • Retains minerals
  • Quick-change filter cartridges
  • No wastewater 
  • Twice the surface area
  • High flow rate
  • Chrome faucet included

Disadvantages

  • Can clog prematurely

Contaminants reduced

  • Sediment
  • Tastes and odors
  • Chlorine
  • Chloramine
  • Lead
  • Heavy metals
  • MTBE
  • VOCs 
  • Bacteria 
  • Cysts
  • Fluoride

Why the TL3 is the best under-sink ultrafiltration filter

The TL3 under-sink ultrafiltration (UF) filter removes 90-100% of particles 5,000 times smaller in diameter than the tip of your hair. Ultrafiltration systems are like RO systems, but they don't remove dissolved particles. A UF filter is the best under-sink water filter for people who want the same quality that RO water provides, but without removing essential minerals. 

Super-fine filter

The hollow-fiber membrane of the Neo-Pure TL3 removes superfine particles (.25 micron), such as lead, VOCs, cysts, and or pesticides. But, it retains dissolved minerals. People love ultrafiltration because it provides clear water without losing the flavor minerals, which brings a unique taste to their water, tea, or espresso. 

Eco-friendly and efficient

You get the most out of a TL3 system at little cost to the environment. Unlike reverse osmosis, ultrafiltration produces no wastewater. This Neo-Pure filter runs efficiently on low water pressure without any help from a booster pump. The hollow-fiber membrane increases the surface area for more extensive filtration.

Because the TL3 does not include a sediment filter, it can clog prematurely. 

How often should you replace the UF filters and UF membrane? Replace the filters once a year and the membrane every two years.

Should you install an under-sink water filter?

Under-Sink Water Filters vs. Countertop Water Filters

Under-sink filter systems are compact and fit underneath your sink. Countertop water filters sit on top of your counter and connect to your faucet. A countertop filter takes up space, and you must disassemble it each time you need to move it out of the way. An under-sink filter stays out of sight and is a more convenient choice. However, if you live in a dorm, rental house, or apartment, you may not be able to install a filter system under your sink. If installing an under-sink filter is not possible, a countertop water filter is the best alternative. 

Under-Sink Water Filters vs. Water Pitcher Filters

If you filter or treat your water at the point of entry for your whole house or from the point of use under your sink, then a water pitcher filter is not necessary. If you want to store filtered drinking water in the refrigerator to keep it cold, then you would use a water pitcher filter to make sure it stays clean and refreshing until you're ready to drink it. 

Under-Sink Water Filters vs. Whole House Water Filters

A whole house water filter treats the water that runs throughout your house at the point of entry (POE). An under-sink filter treats water at the point of use (POU) and is installed right where you need access to clean water. If you have a whole house filtration system, then you may or may not need an under-sink filter as well. Whole house filters come in many forms, so the exact filtration equipment you need depends on the kind of treatment your water needs. Typically, a whole house water treatment goes in conjunction with under counter filtration because you may not treat water in the entire house (that you shower and do laundry with) to the same level of quality as drinking water. 

For example, someone with hard water may need a whole house water softener. A water softener softens the water by adding sodium. In this case, the whole house filter is not used to make the drinking water taste better, but only to treat water hardness. An additional under-sink filter could remove bad tastes and odors, or even the dissolved sodium through reverse osmosis. 

If your water comes from a well supply, then you need to treat it for bacteria before it enters your home or business. A whole house UV system would remove the bacteria, but then you may need an under-sink system to remove other particles from your drinking water. 

If the water coming from a municipal treatment plant is high quality, then you may not need a whole house water filter. An under-sink filter to remove chlorine or chloramines from chemical disinfectants used by the city, as well as bad tastes and odors, would be sufficient.

Learn more about how whole house water filters work.

Types of Under-Sink Water Filters

If you've decided that you need an under-sink water filter, then it's time to determine what type of filtration is suited for your water. If you're not sure about the quality of your water, you can test your water at home with a test kit

filtration spectrum

Reverse Osmosis Systems

An under-sink RO filter is best if your water contains harmful dissolved contaminants, like arsenic, volatile organic compounds (VOCs) in addition to chlorine or sediment.

Reverse osmosis is one of the most thorough methods of filtration. RO systems have several different stages of filtration, including carbon filters, sediment filters, and sometimes, remineralization filters. The RO membrane is the heart of the reverse osmosis system. It removes dissolved particles from water that most other types of filters are incapable of reducing. RO systems are preferred when water needs to be free of anything else. Reverse osmosis is usually not the most economical option for whole house water treatment since it requires a large booster pump and storage tank, but it makes a great under-sink filter.

Read more: What is a Reverse Osmosis System and How Does It Work? | How to Select the Best Reverse Osmosis System

Ultrafiltration Systems

An under-sink UF filter is best if your water contains harmful dissolved contaminants, but you don't want minerals removed.

An ultrafiltration membrane has a slightly larger pore size than an RO membrane, so it removes many of the same contaminants but retains dissolved minerals. Many people prefer to leave beneficial minerals in water for possible health benefits. An ultrafiltration system is efficient on its own and does not need a permeate pump to reduce wastewater. Home water pressure is sufficient for a UF system.

Read more: How an Ultrafiltration Membrane Works | What is an Ultrafiltration System?

Carbon Water Filters

An under-sink carbon filter is best if you need to remove bad tastes, odors, and chlorine or chloramines from water.

A carbon filter removes organic substances and cleans water through adsorption. Chemicals and contaminants stick to the surface of a carbon filter like a piece of Velcro. Certain carbon filters use mechanical filtration to remove lead and cysts as well. Carbon filters are the most effective options for reducing chlorine and making water taste great, but they can't remove dissolved substances. These filters are an excellent choice if your water is free of dangerous contaminants that are more difficult to reduce, like VOCs or arsenic. 

Read more: Activated Carbon Filters 101

Reviews for best under-sink filters from our guests

5 stars for the Neo-Pure TL3

Love it!

I talked to the people at the company prior to this purchase. I had an RO system I could not find filters for and then discovered the amount of waste water I was producing. This system has none and I just love the taste. -- Kelly

Very pleased.

I’m very pleased with the TL3. It is a good source of water free from contamination and it does not take up much space in your kitchen. I also bought a second TL3 for my mom!! -- Jose

5 stars for the Everpure ADC

We will by this product again.

We do use it on our fifthwheel. We are very happy with the Overture ADC RV Water Filter Cartridge because without the water we do drink has no taste. -- Yolaine

Perfect fit for an older model RV.

I have an older model Class A RV and had trouble finding a filter locally. UIT arrived in a couple of days, connected easily and the water tastes great. -- Darren

5 stars for the K-NPQ1 replacement filter

These filters are great!

They are easy to install and the water tastes great! Thank you. -- Dawn


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