Worried about your drinking water? Looking for something that has the same refreshing quality you find in purified store-bought water? Using an at-home under sink water filter can help you achieve this in the comfort of your own home.
It’s worth taking your time when shopping for just the right water filter. We’ll show you how, plus share our top picks for the best under sink water filters on the market.
What Is an Under Sink Water Filter?
An under sink water filter is a filtration system that’s mounted underneath your sink and countertop. Like a carafe or countertop water filter, it removes contaminants and impurities from your drinking water. This will leave you with healthier water that tastes much better.
Although all water filtration systems can improve your water, an under-sink model doesn’t have to be prepped. Once it’s tied into your system, consider the filter to be active whenever you turn the faucet on. There’s no need to worry about refilling a carafe or cluttering your countertop or refrigerator.
Different Types of Under Sink Water Filters
While all under sink water filters are mounted under the sink, the way the filtration system works can vary. There are two most common types of water filters you’ll come across: reverse osmosis and charcoal.
Reverse osmosis filtration systems are considered the gold standard of at-home filters. They’re capable of removing a wide variety of contaminants and come in both large and small units.
Although this variety does an excellent job, the biggest drawback is the speed at which water passes out of the faucet.
Reverse osmosis filters provide fresh and safe water. Just be aware that they also require more comprehensive maintenance. Many systems are complex and may be challenging for an inexperienced handyman to put in on their own.
- Removes many different kinds of impurities.
- Works on all water types.
- Leaves you with great tasting water.
- Can be challenging to install.
- Generally more expensive with more upkeep.
Carbon filtering uses active charcoal carbon filters to remove impurities from the water. It works very well on removing chlorine, sediment, and VOCs, leaving you with odor-free, better-tasting water.
These versions are quite environmentally friendly and can be very affordable. They’re straightforward, and while they do require maintenance, replacement filters are inexpensive and easy to swap out.
- Space-saving and easy to install.
- Can be used on most plumbing systems.
- May need frequent filter replacements.
- Won’t filter all impurities.
How to Choose the Best Under Sink Water Filters
Consider how relevant the following are to your situation:
- Test your water: It’s easy to test your water using an at-home water test kit. A simple test can tell you what kind of impurities you have, allowing you to narrow your field of options (1).
- Look for soft water: You want your water to be odorless and to taste great. Soft water will give you the refreshing taste you’re looking for, so hone in on those models that can convert hard water to soft.
- Consider the output rate: Every water filter system will come with an output rate. This measurement lets you know how quickly the unit can filter your water. The higher the output rate, the faster your fresh-tasting water will be delivered.
- Check compatibility: If you have an older or non-standard sink, you especially need to make sure the filter you select works with your system. If your plumbing is difficult to outfit, you may want to consider working with a professional for installation.
- Factor in maintenance and ease of use: There are complicated systems out there. If you plan on installing and maintaining yourself, look for units that are easy to work with and require minimal maintenance.
- Consider using a multistage system: If you’re looking for truly refreshing water, such a system may be the way to go. The water runs through individual canisters designed to remove a specific contaminant for a great tasting and healthy water supply.
- Establish your budget: A simple charcoal unit can do a great job of removing contaminants without breaking the bank. A more sophisticated system may remove more, but its capabilities are reflected in its price. Know what you’re looking for in a filter and how much you plan to spend before you start shopping.
On City Water?
The Best Under Sink Water Filter Reviews of 2021
Have an idea of what you might be looking for in your new under sink water filter? We’ve consulted the experts and heard from real-world users. Now it’s onto our favorite under sink water filters.
1. CuZn UC-200 Under Counter Water Filter
With its small footprint, this model is suitable for use nearly anywhere.
It’s easy to install and low maintenance. Designed to process 50,000 gallons of water — or for five years of use — you won’t need to worry about ongoing maintenance.
A multistage processing system gives you comprehensive filtration and addresses common water problems. Test your water before bringing this unit home as it won’t have a significant impact on some impurities, including fluoride. It is bacteria and mold-resistant, though, which helps keep it functioning well for longer.
This product is designed to be used with city water only. While installation is easy on standard plumbing set-ups, it can be modified for non-standard plumbing. Customer service can be contacted for an additional installation kit or to answer any questions.
Why We Love It
This unit comes with a five-year prorated warranty that covers product or component failure. It also comes with a great 90-day money-back guarantee that ensures your satisfaction with the product. If it doesn’t perform to your expectations, you can expect your return to be hassle-free with no questions asked.
Easy to Install
An excellent option for a first-time installer, everything you need to complete the installation is included. Remove the hose, tie in the new unit and your filter begins working immediately — it hooks directly into the existing cold water line.
Some under sink water filters require additional faucet or water lines. For this installation, anticipate needing only an adjustable wrench. If you find you’re stuck during the process, a detailed instruction manual and a how-to video are included to help you.
Although this is a single enclosed unit that doesn’t take up much space, it still has a multistage filtration process. Acid-washed coconut shell and activated carbon target offensive odors and unpleasant taste.
A micro sediment membrane works to remove debris and particles. One more stage, using KDF-55 filtration media, targets bacteria and inorganic contaminants such as lead and heavy metals.
The three-step filtration process leaves you with great-tasting water that has fewer contaminants.
No Filters to Replace
Designed to work for five years (or after you’ve processed 50,000 gallons of water), there’s no need to swap out filters. When the time comes, remove the whole unit and replace it with a new one. This keeps maintenance easy and straightforward, with no interim care between replacing units.
Keep In Mind
Not for Well Water
This filter is made for municipal water only as this water is already regulated and falls within specific parameters. Despite this filtration method being a fantastic option for light filtration of city water, it’s not heavy-duty enough to tackle well water.
If you have a well, opt for something larger and more sophisticated as a primary filtration system.
|Dimensions||4.5 inches by 4.5 inches by 15 inches|
|Installation Method||Directly connect to cold water hose; necessary installation components included|
|Flow Rate||2 GPM|
2. Frizzlife Under Sink Water Filter System
A two-stage filtration system is designed to remove the bulk of heavy-metal contaminants from your drinking water. Mercury, rust, other organic compounds, and carcinogens are all removed by this filtration system. In the process, bad odors and unpleasant tastes are also taken out of the water.
This unit is suitable for use on both ½-inch and ⅜-inch cold water lines. Converter fittings are included to make installation quick and easy. A built-in shut-off valve gives you extra control during filter changes.
Each system is designed for high capacity and will work for two years or through the processing of 1,600 gallons of water. For optimal performance, plan on replacing the inner filter every 6 to 8 months.
Why We Love It
Great for Removing Lead
This is an excellent choice if you’re looking for something to clear your water of heavy-metals. Its two-stage filtration technology uses 0.5 microns of carbon. This is a sophisticated compound filter that can remove 99.9 percent of lead in your drinking water.
Not only is this unit affordable to purchase and install, but it’s also affordable to maintain. The inner filter costs much less to replace than enclosed plastic filter models. This means you’ll save money upfront and in the long run.
More affordable filters also mean you can replace your filter more often, letting you enjoy fresh-tasting water at all times.
Won’t Interfere with Essential Minerals
Although this filter does a great job at removing impurities from your drinking water, it’s intentionally designed to leave essential minerals behind. Calcium, potassium, sodium and magnesium — all building blocks for a healthy body — remain in the water.
If you have an imbalance in any of these essential minerals, including fluoride, post-filtration, you may want to consider an alternative filter.
Installation Components Included
We love that installation is quick and easy. This is a direct connect system that ties right into your existing hose. Anyone can use the twist-in design, and it takes less than three minutes to set up or change.
Included with this filtration system are the following components: filter system, converter, two wrenches, water tape, three screws, one inlet hose and one outlet hose. No additional installation materials are required.
Keep In Mind
Only for Use with City Water
This model isn’t designed for heavy-duty filtration needs. Larger impurities and contaminants found in totally untreated water — like that from a well source — can easily clog the filter.
Even if it’s still usable, contaminants like this can cause the water flow to be greatly decreased, and the filtration process slowed significantly.
|Dimensions||13.8 inches by 5.6 inches by 5.3 inches|
|Installation Method||Direct connect to cold water hose; necessary installation components included|
|Flow Rate||2 GPM|
3. Woder 10K-Gen3 High Capacity Filtration System
An excellent option for reducing turbidity, odors, and undesirable particles in your water.
This filtration system is easy to install and has great longevity, which means maintenance is minimal. Plan on swapping out the filter cartridge every few years, or every 10,000 gallons, to keep the water tasting fresh.
No additional plumbing work is needed, and it’s suitable for a novice to install on their own. This is a direct connect model that screws into the existing cold water line; it shouldn’t be used with hot water. Additional components needed to complete installation are included with this product.
Why We Love It
Provides High-Quality Drinking Water
We love that this unit removes a lot of those heavy-metal contaminants you don’t want to see in your water. It’s designed to target rust, mercury, lead, chromium 6, and VOCs while reducing odor and taste issues.
Not only does this unit take out the nasties, but it also leaves behind the good stuff! Magnesium, calcium, potassium, and other essential minerals remain intact to provide healthy and great-tasting water.
This is a high capacity unit that’s designed to work for three years without needing to be replaced. That’s 10,000 gallons of water this unit can filter.
Replacement cartridges are easily available when it’s time to refresh your filtration system.
Simple to Install
Even inexperienced DIY individuals can successfully install this unit.
It’s a direct connect wall-mounted option that screws into the existing cold water connection line. Two hoses, the filter, and the head with built-in valves are included with this product to make installation fast and easy.
Filters Are Fully Tested
This model — and all filters in the Woder line — has been extensively tested. It passes the National American Standards Institute requirements when tested through independent laboratories. The result? Expect a high-quality product and healthy, great-tasting water.
Keep In Mind
Not Recommended for Hot Water Use
Using this filter with hot water will diminish its life expectancy. While the filter will still work and filter the water efficiently, you’ll be damaging it over time.
You’ll also want to stay away from heavy sodium and softened water to prolong the filtration system’s life.
Not Suited for Well Water
Like other small filters, this version is designed for city water that’s already been treated. Such water has had rough sediment and strong imbalances removed. This makes it suitable for the lighter-duty filtration these systems provide.
If you have a well you’re looking to filter, you may want to turn to a whole-house filtration system instead.
|Dimensions||3 inches by 3 inches by 15 inches|
|Installation Method||Direct connect; installation components included|
|Flow Rate||2 GPM|
4. iSpring RCC7AK 6-Stage Water Filter System
If you’ve been looking for a little more from a water filtration system, you may want to consider this unit. It’s a reverse osmosis system that’s made to fit in tight spaces while both filtering and softening your water.
Although not recommended for well water use, the same model equipped with UV filtration is available and appropriate for well water. This unit is capable of processing 75 gallons of water a day.
Why We Love It
Thoroughly Removes Contaminants
A heavy-duty system, this filter can remove over 99 percent of more than 1,000 different contaminants found in water. This includes common impurities like lead, arsenic, chlorine, and fluoride. You’ll also find there’s fewer bacteria and viruses in your water when using this system — it can even combat persistent giardia.
Many other reverse osmosis systems have only five stages of filtration. These units still do an exceptional job of removing contaminants, but they’re so efficient that they strip the water of essential nutrients too. This can leave you with nutrient-deficient water that’s on the acidic side.
The sixth stage present in this system works to put those minerals back into your water. It leaves you with balanced water that tastes natural but is free of impurities.
The quality of the components used means your filter will last you longer and require less maintenance during its lifetime.
The first stage’s housing canister is clear, allowing you to check in on the primary filter’s status easily. Visual assessment is quick and tells you when it’s time to replace your filter.
These filters have been extensively tested to ensure there are no leaks or drops in water pressure. Not only does this leave you with a more efficient filtration system, but it also prevents leaking, which could damage your home.
This model is approved for drinking water but does come with a “Prop 65” warning due to the PVC used in its construction. The warning is included for public awareness and required by California law.
Keep In Mind
Complicated to Install
Reverse osmosis systems are more complicated and take longer to install than direct connect units. If you aren’t sure about the process, consider hiring a plumber to complete the installation.
|Dimensions||14.5 inches by 5.2 inches by 18.5 inches|
|Installation Method||Wall-mounted; installation components included|
|Flow Rate||.05 GPM|
5. APEC Top Tier 5-Stage Water Filter System
Made with tight quarters in mind, this is a reverse osmosis system that’s intended to fit easily under your kitchen sink.
It offers a five-step filtration system that removes 99 percent of water contaminants. Not only will debris and sediment be removed, but so will harmful chemicals and organic agents, like viruses and bacteria.
Included with this unit is a 100 percent lead-free faucet and an FDA-certified food-grade tubing to complete your installation. This ensures no impurities will sneak into your water between the filtration system and your open faucet.
Why We Love It
Suitable for Well Water Use
This APEC model is ready to tackle all kinds of water sources, even those that haven’t previously been treated. It’s capable of filtering out 1,000 different contaminants and leaves your water fresh-tasting and free of impurities. Of course, this filter is also appropriate for use on municipal water as well.
Upon registration, you also receive a two-year extended warranty that covers your product for defect or damage. It’s guaranteed to remove 99 percent of your water’s impurities and to remain leak-free.
Top-quality materials have been used in the construction of this reverse osmosis filter.
It’s clearly labeled for easy installation and maintenance. The product has been designed and engineered in the United States. While components were manufactured elsewhere, all assembly occurs in the United States.
Customer Support for Installation
Installing a sophisticated water filtration system like this can be complicated. Fortunately, this filter comes with an easy-to-follow instruction manual. While it may be more complicated than others to set up, it’s designed for homeowners to install on their own.
If you run into any difficulty during installation, customer service is available to walk you through the process. A video tutorial is also available to make installation a breeze.
Keep In Mind
You’ll Lose Healthy Minerals
This filter does a fantastic job of removing the nasties in your drinking water. However, during the filtration process, you’ll also lose many of the minerals you do want — ones that your body needs for optimal health.
You may want to consider adding some of those minerals back into your water or compensate with supplements. Regularly test your water and keep track of any health changes you experience.
|Dimensions||16 inches by 5.2 inches by 17.5 inches|
|Flow Rate||0.03 GPM|
6. Filtrete Advanced Under Sink Water Filtration System
This small filter packs a tremendous punch, capable of removing rust, sediment, chlorine, and negative odors and tastes. It’ll reduce existing contaminants in your water by more than 99 percent. Despite being so powerful, water flow won’t be impeded, which is a bonus.
Installation is quick and easy, taking less than half an hour. Keep in mind that you can use this filter safely anywhere outside of the kitchen — something to think about before installation.
Plan on replacing the filter every six months. More heavy-duty Filtrete filters can be used interchangeably with this system.
Why We Love It
You don’t have to worry about space with this filter, making it a great choice for nearly any under-sink area. It’s designed to be mounted against the wall, tying directly into the cold water line.
Multiple Filter Options
This system comes equipped with the Filtrete Advanced filter. However, it’s designed to work with other filters in the same line. You can choose from Maximum, Advanced and Standard filters to get exactly the kind of filtration your water needs.
Straightforward installation will have your new water filter set up in just a few minutes.
Start by turning off the water, and then connect the supply hose to the quick-connect outlet on the filter head. Attach the second supply hose to the other quick-connect point on the filter head.
Once the head is fully installed, it takes just a quarter of a turn to lock the filter into place. Turn the water back on, and you’re up and running.
Great Water Flow
Offering a water flow of 2.25 GPM, this unit provides fast filtration. It’s intended to last through the processing of 2,000 gallons of water and should be replaced every six months.
If your water has more sediment, or if you use more water than the average household, you may need to replace it more frequently.
Keep In Mind
You May Need a More Substantial Filtration System
Intended for light-duty filtration needs, this filter may not be sufficient for heavy-duty filtration.
Although this filter won’t slow down water flow, it can become clogged with larger sediment or debris. If your water has a lot of impurities, as is the case with well water, you may want to consider a different kind of water filter. Consider the APEC filter above or the Express Water one below.
Double Check Your Hoses
This product comes with most of what you need to complete your installation. Standard sink hoses are usually 1/2-inch or 3/8-inch.
While other options include fittings for conversion if needed, this one doesn’t. To complete your installation, you’ll need to make sure this unit works with your hoses, or buy the needed components separately.
|Dimensions||4 inches by 6.8 inches by 14 inches|
|Installation Method||Wall-mounted direct connect|
|Flow Rate||2.25 GPM|
7. Express Water Ultraviolet Reverse Osmosis Filter
If you’ve been searching for an under sink water filter that can handle heavy-duty filtration needs, don’t skim over this one.
Its 11-stage filtration process removes contaminants, keeps your water mineral-rich, and leaves it tasting fresh and clean. Odor, sediment, and other impurities are easily removed from your water without impacting convenience or slowing flow rate.
Although this option is more complicated to install than others, it’s designed to be user-friendly. A color-coded set-up system helps keep you organized during installation and cartridge replacement. This makes self-installation highly achievable.
It’s been tested and certified by independent laboratories and comes with a one-year warranty.
Why We Love It
11 Different Stages of Filtration
Each stage works to target a different issue, leaving you with deliciously fresh water that’s free of impurities.
Stages 1–5 work as you would expect in a traditional reverse osmosis unit.
Stages 5–9, the alkaline filter stages, add back in those nutritious minerals that have been stripped from the water.
Stage 10 uses an ultraviolet filter to destroy harmful microorganisms such as E.coli.
In the final stage of filtration, the water is passed back through a post-activated carbon filter to ensure it’s fresh-tasting.
Approved for Use with Well Water
This may be an under sink filtration unit, but it’s ready to deal with the toughest of water sources, such as previously untreated water, well water, and natural water sources.
Equipped to remove organic microorganisms, bacteria, and viruses, you can rest assured knowing your water is safe for consumption.
Reverse osmosis systems are more sophisticated, and it takes longer for the water to make its way through them. This unit processes 0.8 GPM and can filter 100 gallons of water per day.
This filter can be used anywhere; the home, apartment, office or an RV. This is a huge bonus since other comparable products are only designed for niche use in certain spaces.
Keep In Mind
It’s Not Compact
With multiple cartridges to complete the 11 stages of filtration, it’s not compact. Even if you have ample under sink space in your kitchen, you may lose most of that space to this filter.
Needs to Be Maintained
You’ll love the complex filtration process and great-tasting water. However, if you’re looking for a unit you can set up and walk away from, this isn’t it. The pre-filters (sediment, carbon block, and granular activated carbon) need to be replaced twice a year.
The rest of your filters will need to be replaced yearly. Although filter changes are designed to be quick and easy, they’ll still be on your to-do list. Replacing filters will also add cost to keeping your system running.
|Dimensions||15 inches by 14 inches by 5 inches|
|Flow Rate||0.8 GPM/100 gallons a day|
|Product||Best For||Weight||Dimensions||Installation Method||Flow Rate||Capacity|
|CuZn UC-200 Under Counter||First-Time Installers||8 lbs||4.5″ x 4.5″ x 15″||Directly connect – cold water hose; necessary installation components included||2 GPM||High capacity|
|Frizzlife Under Sink||Budget Filtration System||4.35 lbs||13.8″ x 5.6″ x 5.3″||Direct connect – cold water hose; necessary installation components included||2 GPM||High capacity|
|Woder 10K-Gen3 High Capacity||Low-Maintenance||2.85 lbs||3″ x 3″ x 15″||Direct connect; installation components included||2 GPM||High capacity|
|iSpring RCC7AK 6-Stage||Preserving Minerals||20 lbs||14.5″ x 5.2″ x 18.5″||Wall-mounted; installation components included||.05 GPM||High capacity|
|APEC Top Tier 5-Stage||Budget RO System||25 lbs||16″ x 5.2″ x 17.5″||Wall-mount||0.03 GPM||High Capacity|
|Filtrete Advanced Under Sink||Small Spaces||3.17 lbs||4″ x 6.8″ x 14″||Wall-mounted direct connect||2.25 GPM||High capacity|
|Express Water Ultraviolet Reverse Osmosis||UV RO Filter||30.2 lbs||15″ x 14″ x 5″||Wall-mount||0.8 GPM/100 gal. a day||High capacity|
Finding the Best
Bringing home a new water filter can leave you with healthy, great-tasting water. Whether you have city water or a natural water source, there’s a filter out there that can work for you. Start by identifying what contaminants you need to target, and work from there to find the model that will suit you best.
What water problems are you looking to correct with a filter? We’d love to hear which option you go with and how it works for you. Leave us a comment in the section below!