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
- Neo-Pure Residential 4 Stage RO System: Best under-sink RO system
- Pentair Freshpoint 3 Stage Reverse Osmosis System: Best under-sink filter for RVs
- Aqua Flo UVB1: Best under-sink UV system
- Neo-Pure TL1-C302: Best under-sink system to use in place of a refrigerator filter
- Watts Kwik-Change 3 Stage: Best under-sink ultrafiltration system
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.
Best Under-Sink Water Filter Reviews
Neo-Pure Residential 4 Stage Residential RO System - Best Reverse Osmosis Under-Sink Filter
Advantages
- Many configuration options
- Comes preassembled
- Excellent value
- Simple installation and maintenance
- Permeate pump included
- Remineralization postfilter
Disadvantages
- Faucet not included
Contaminants reduced
- Sediment
- Bad tastes and odors
- Chlorine
- Dissolved inorganic contaminants
- Chemicals
Why the Neo-Pure Residential 4 Stage RO System 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 Residential 4 Stage RO System provides your kitchen with clean, crisp water.
Easy installation and maintenance
This system delivers to your door preassembled. As a result, the installation process is simple. Alongside its easy installation, the Neo-Pure’s quarter-turn cartridge replacement system makes routine maintenance simple and quick. The replacement cartridges for this system are industry standard, keeping maintenance costs at a minimum. Only the cartridges, not the plastic housings, reach the landfill, minimizing plastic waste.
Remineralization postfilter
The Neo-Pure remineralization cartridge reintroduces beneficial calcium back into the filtered water while also raising alkalinity and pH. This filter gives the final product a pleasant, refreshing flavor that is ideal for drinking and cooking.
How often to replace cartridges
Neo-Pure systems offer the convenience of purchasing 6-month and 12-month cartridge replacement kits. These kits provide all the components you need to keep your system up and running. The 6-month kit includes two 5-micron carbon block filters and one inline remineralization filter. The 12-month kit includes two 5-micron carbon block filters, one inline mineralization filter, one RO membrane filter, and an RO sanitizing maintenance kit. When purchasing a 12-month kit, ensure you select the product with the correct RO membrane output.
Pentair Freshpoint 3-Stage Reverse Osmosis System - Best Under-Sink Water Filter for RVs
Advantages
- Fits in tight spaces
- Click-to-lock filter cartridges
- Color-coded cartridges
- Easy installation
Disadvantages
- No scale control for locations with hard water
Contaminants removed
- Sediment
- Bad tastes and odors
- Chlorine
- Dissolved inorganic contaminants
- Chemicals
Benefits of the Pentair Freshpoint for RVs
The Pentair Freshpoint 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 is what makes the Pentair Freshpoint a great RV reverse osmosis system:
Compact design
The Pentair Freshpoint is an excellent system because of its compact design. The filter housings open toward you, allowing you to pull the filter forward and replace it in no time. Other under-sink RO systems need additional clearance above or below to remove the housings and change the filters.
Click-to-lock cartridges
The FreshPoint filters are considered "quick-change" because they can be replaced with a single click. Keep in mind that ease of maintenance comes at a cost to the environment. The FreshPoint filters are encased in plastic that will end up in a landfill.
How often to replace the RO filters
- Prefilter: Twice a year
- RO membrane: Every 3 years
- Postfilter: Once a year
Aqua Flo UVB1 2 GPM UV System - Best UV Under-Sink Water Filter
Advantages
- Carbon block prefilter
Disadvantages
- No sediment filtration
- Heats water up
Contaminants removed
- Bacteria
- Chlorine
- Foul tastes and odors
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 Aqua Flo UVB1 is unique because it not only treats water for bacteria, but it includes filtration to remove foul tastes and odors as well.
Disinfection plus filtration
The Viqua DWS disinfects water with UV light and includes a carbon prefilters which means it reduces more contaminants than other UV systems. This UV removes bad tastes, odors, and chlorine with the carbon filter.
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 TL1 - Best Under-Sink Water Filter to Use in Place of Refrigerator Filter
Advantages
- Removes foul tastes and odors
- Lead reduction
- Removes cysts
- Quick change filter cartridge
- Compact filter size
Contaminants reduced
- Lead
- Cysts
- Chlorine
- Foul tastes and odors
Why the Neo-Pure TL1-C302 is the best under-sink filter to use in place of a refrigerator filter
The Neo-Pure TL1-C302 is a simple but powerful filter that cleans water for your kitchen faucet. Any of the under-sink water filters recommended can connect from your sink to your refrigerator, but the Neo-Pure TL1-C302 works best with appliances. Here's why:
Removes foul tastes and odors
When chlorine and chloramine are added to a city water supply to kill bacteria, they give the water an unpleasant chemical taste. The Neo-Pure TL1-C302 removes chlorine and chloramine, leaving water with a clean, crisp taste.
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 TL1-C302 filter has microns small enough to block these dangerous contaminants from passing through.
The TL1-C302 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? About twice every year.
Watts Kwik-Change 3 Stage Drinking Water System - 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
Contaminants reduced
- Sediment
- Tastes and odors
- Chlorine
- Chloramine
- Lead
- Heavy metals
- MTBE
- VOCs
- Bacteria
- Cysts
- Fluoride
Why the Watts Kwik-Change is the best under-sink ultrafiltration filter
The Watts Kwik-Change under-sink ultrafiltration filter removes 90- 100% of particles 5,000 times smaller in diameter than the tip of your hair. Ultrafiltration systems are similar to RO systems, but they don't remove dissolved particles. A UF filter is the best under-sink water filter for people want the same quality RO water provides, but without removing essential minerals.
Super-fine filter
The hollow-fiber membrane of the Watts Kwik-Change removes superfine particles (.25 micron) like lead, VOCs, cysts, and or pesticides, but it retains dissolved minerals. People love ultrafiltration because it provides them with clear water without losing the flavor minerals bring to their water, tea, or espresso.
Eco-friendly and efficient
You get the most out of a Watts Kwik-Change system at little cost to the environment. Unlike reverse osmosis, ultrafiltration produces no wastewater. This system 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.
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 or a rental house or apartment, you may not be able to install a filter system under your sink. When installing an under-sink filter is not possible, a countertop water filter is the best alternative.
Explore our picks for the 5 best countertop water filters.
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 pitcher filter to make sure it stays clean and refreshing until you're ready to drink it.
Explore our picks for the 5 best water pitcher filters.
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 too.
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 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 also 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. | Explore our picks for the 5 best whole-house water filters.
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.
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 or 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
If you have any additional questions, please do not hesitate to contact us.