Runner Up
Our #1 Choice
Best Rated
Finding a solution for filtering your home's drinking water should be at the top of everyone's To-Do list. Even if your tap water looks clean and clear and tastes just fine, who knows what micro-contaminants could be floating around in there? An easy way to rid your tap water of these contaminants is with the help of an under sink water filter.
This type of filter is installed beneath the kitchen sink, which means you won’t have to worry about a large filtration device taking up counter space or taking away from your home’s aesthetics. Use this complete guide on the best under sink water filters to fulfill your hydration needs.
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Under Sink Water Filters Compared
Preview | Product | Minimum Water Pressure | Water Waste/Pure Water Ratio | Check Price |
---|---|---|---|---|
Home Master TMAFC-ERP | 40 PSI | 1:1 | ||
iSpring RCC7AK | 45 PSI | 3:1 | ||
CuZn UC-200 | 40 PSI | No Waste | ||
APEC Top Tier | 40 PSI | 3:1 | ||
APEC WFS-1000 | 20 PSI | No Waste | ||
Filtrete | 25 PSI | No Waste | ||
AO Smith | 25 PSI | No Waste | ||
Aquasana AQ-5300+.55 | 25 PSI | 3:1 |
Types of Under Sink Water Filters
Buying Guide: Under Sink Water Filters
Type of Filter
Every filter has the potential to remove contaminants, but the pollutants removed are different from filter to filter. The filtration technology that is used with RO is different than that of a conventional or simple filtration unit, so you must look at the list of contaminants removed by a filter before deciding.
In order to do that, you need to first know the contaminants within your tap water. This is actually relatively simple and can be done with a simple water testing kit (purchase on Amazon). By testing your water, you’ll be able to see exactly what you’re working with. You can then choose a filter depending on whether your home’s drinking water has high levels of chlorine, fluoride, lead, or something else.
Filtering Capacity and Stages
Filtering capacity refers to the number of gallons or liters a unit can filter before it’s time for a replacement. Most under sink water filters have a high capacity or 1,000 gallons or more, which means you won’t have to change the filter until it has reached this capacity. In most cases, you should be able to get a full year of usage before needing to replace the filtration cartridge.
In terms of filtration stages, a good rule of thumb to follow is this: the more stages a filter goes through, the cleaner the final product with be. Using a 5-stage filter means that the water goes through 5 stages of filtration before delivering the clean water through the faucet. If possible, look for a filter that comes with a 5 or even 10-stage filtration process.
Waste vs. Pure Water Ratio
According to Pacific Water Technology, here’s what waste to pure water ratio means:
“Residential RO systems have a waste: pure water ratio that is set by the membrane supplier. The ‘waste’ water is required to flush the membrane and ensures that you can achieve a reasonable life span of 2-3 years before having to replace the membrane.
Any low ratio like 1:1 will ensure that the membrane needs to be replaced well before the typical life expectancy…”
This ratio is only important to consider if you’re thinking about investing in a reverse osmosis filter.
Filter Life and Cartridge Longevity
Filter life depends on several things, mainly the filtration capacity, but also the state of your home’s water. The more contaminants in your water, the harder your filter needs to work to filter out those contaminants. The main thing to look at is a high capacity for the filtration cartridge since the higher the capacity, the longer the lifespan.
Most under sink filter and refrigerator filter manufacturers recommend replacement either once per year or once every six months. This is why it is crucial to look into the cost of replacement filters before choosing a filtration unit. For high filter replacement costs, you could be spending hundreds of dollars each year changing out the unit’s filter cartridges.
Operating Water Pressure/Flow Rate
Since these filters require the water to move upwards from beneath the sink to the kitchen faucet, pressure is needed to make that happen. This pressure is measured in pounds per square inch (PSI), and the higher the pressure, the faster the flow rate. However, you also need to consider that a higher pressure means that the water will not spend as much time in the filtration chamber. If your water is highly contaminated, high pressure should definitely not be your first priority.
Healthy Minerals Added
Remineralization is a process that many filters offer, but not all of them. During the filtration process, everything is filtered out from the water. This means that all the bad things are removed, but so are the healthy aspects of h20. Minerals like calcium, magnesium, and potassium are filtered out along with the harmful bacteria, viruses, and heavy metals.
This is why so many filters come with a remineralization stage. After filtration, remineralization works to add the lost minerals back in. Not only will your water be infused with healthy minerals, but through this process, the water is often alkalized. This means that it becomes less acidic (the pH level goes up). Many sources are saying that there are a lot of health benefits of drinking alkaline water.
Ease of Installation and Filter Changes
The most difficult under sink filter to install is one that utilizes RO, and often it is worth it to hire a professional plumber. For the easiest installation possible, you'll want a simple filtration system. This type requires no additional faucet for the filtered water. The next most accessible kind of filter to install is the conventional system, but with this, it is necessary to install a separate faucet for the filtered water to be dispensed.
Not only is it essential to consider the ease of initial installation, but also the ease of replacing the filter cartridges. Changing out the filter every year doesn’t need to be challenging when you invest in an easy-to-use system. In most cases, you’ll simply twist the current cartridge out of place and replace it with a new one.
Certification
The principal certifying organization for water filters is the NSF, so it's a good idea to keep an eye out for NSF-certified products and systems. There actually aren’t that many NSF-certified products out there since the certification process is lengthy, but you should at least look for a product that meets NSF standards. Even better is finding one that has been officially certified by the organization, specifically standards 48, 52, and 401. For RO systems, look for the NSF 58 cert.
Price & Warranty
Even though having access to clean drinking water is crucial, there’s no need to break the bank. Sure, some filtration systems cost more than others, but even if you're on a budget, you should be able to find an effective filter for under the sink. More important than the initial cost of the system is the cost and expected lifespan of each replacement filter cartridge.
With every home fixture purchased, looking into a product’s warranty procedure is an essential part of the buying process. Warranties vary depending on the manufacturer but try to find a filtration system that comes with at least a 5-year warranty period.
8 Best Under Sink Water Filters Reviewed
1. Home Master TMAFC-ERP
Our Top Pick!
Minimum Water Pressure | 40 PSI |
Water Waste/Pure Water Ratio | 1:1 |
Contaminants Removed | Iron, Chlorine, Lead, Chloramine, and More |
Filtration Media | Mechanical |
Filter Life | 1 Year |
Warranty | 5 Years |
Our top pick for best under sink water filter is the Home Master TMAFC-ERP, which uses highly effective reverse osmosis filtration to filter out contaminants. It utilizes seven stages of filtration to leave your water tasting fresh, but more importantly, to filter out up to 98% of chemicals, like lead, chlorine, chloramine, bacterial, and other heavy metals.
After your water has been thoroughly filtered, the Home Master puts it through a remineralization process to add back all the calcium and magnesium that was lost during filtration. Although installing an RO system can be challenging, Home Master has done all that they can to make TMAFC-ERP installation as simple as possible. This is especially true when it comes to changing out the filters, which only needs to be done once per year thanks to the units 2,000-gallon capacity.
One thing that many people are concerned with when it comes to RO systems is the waste aspect. This isn’t something you need to worry about with the Home Master; it works to reduce water waste by up to 80% and increase water production by up to 50%. This is all possible thanks to the built-in non-electric permeate pump, which also contributes to fast flow rates, no housing leaks, and no acidic water.
There are tons of RO systems for under-sink installation to choose from, but you honestly can't go wrong with the Home Master model. Aside from complicated installation and high initial cost, there is nothing bad to say about the TMAFC-ERP. Just keep in mind that you may need to hire an expert with installation if you aren't familiar with your home's plumbing.
Pros
Cons
2. iSpring RCC7AK
Runner Up
Minimum Water Pressure | 45 PSI |
Water Waste/Pure Water Ratio | 3:1 |
Contaminants Removed | Lead, Chlorine, Fluoride, Arsenic, Hormones, Asbestos, Calcium, Sodium, Bacteria, Giardia, Viruses, and More |
Filtration Media | Mechanical |
Filter Life | 1 Year |
Warranty | 1 Year |
Our runner up for best-rated under sink water filter is the iSpring RCC7AK. This model utilizes high-capacity reverse osmosis filtration to produce safe and healthy drinking water. It softens your water while also removing up to 99% of contaminants - over 1,000 of them. This includes lead, chlorine, arsenic, hormones, bacteria, and cysts like Giardia.
Not only does the RO membrane of the RCC7AK remove harmful pollutants, but it also adds back helpful minerals while also reducing the water’s acidity. In fact, the 6th stage of the filtration process is all about alkalization. Most RO systems skip this step, but not this model. In the 6th stage, the minerals are added not just to remineralize the water supply, but also alkalize it for optimal health benefits.
The company says that installation is an easy DIY project, but some reviewers seem to disagree. It all has to do with whether or not you’re comfortable with plumbing projects, but if you are, you should have no trouble installing the unit yourself. It fits under all standard kitchen sinks, but whether or not you do it yourself is up to you. We recommend hiring a pro if you have no experience with filtration systems like these, though.
All in all, this is a fantastic choice for RO under-the-sink filtration. The only reason we didn't name it as our top pick is that it does produce quite a bit of waste compared to the similar Home Master model. Compared to the Home Master, which is a 1:1 ratio of waste to useable water, this one has a 1:3 ratio.
That means it produces 3 units of waste to every 1 unit of pure water. This is actually fairly standard, but if you’re looking for something with less waste, go with the top pick.
Pros
Cons
3. CuZn UC-200
Best Rated
Minimum Water Pressure | 40 PSI |
Water Waste/Pure Water Ratio | No Waste |
Contaminants Removed | Chlorine, Lead, Mercury, Chromium VI, Cadmium, Herbicides, Pesticides, Sediment, Algae, Molds, and More |
Filtration Media | Biological |
Filter Life | 5 Years |
Warranty | 5 Years |
Another excellent choice for your home’s under kitchen sink water filter is the CuZn UC-200. This top-rated model has received extremely high marks among reviewers around the world. The main reason is that it has an unbelievable filtering capacity of 50,000 gallons. Compared to filters that feature a capacity of 2,000 or 6,000 gallons, this is extremely impressive. This means that you can potentially go 5 years without needing a replacement filter!
Before reading on, you should know that the CuZn is not suitable for well water; it was designed to filter municipal water sources only. But since most of us utilize a municipal water source, this feature doesn't rule too many people out. Also, if you have hard water in your household, this filter was not designed to resolve that issue. It does not soften water, it merely filters it, but it does so very effectively.
To filter your water, this system uses 3 stages of filtration, including micro sediment membranes, KDF-55, and coconut shell carbon. Each of these filter mediums is highly effective forms of filtration, so you can rest easy knowing that you and your family are drinking only the best water in town. Another perk is the beyond-easy installation, which can be done without the help of an expert, thanks to the fact that this connects directly to the kitchen sink's cold water line.
Aside from the fact that this is a fairly basic model - it does not remineralize, it does not alkalize, and it does not soften - the high ratings from reviewers speak for themselves. If you want something that is low maintenance and only needs filtration replacement once every 5 years, this is it!
Pros
Cons
4. APEC Top Tier
Best Drinking Water Filter
Minimum Water Pressure | 40 PSI |
Water Waste/Pure Water Ratio | 3:1 |
Contaminants Removed | Arsenic, Barium, Cadmium, Chromium, Fluoride, Copper, Lead, Radium, and More |
Filtration Media | Mechanical |
Filter Life | 1 to 2 Years |
Warranty | 2 Years |
The best under sink water filter system for producing the best-tasting drinking water is the APEC top tier filtration system. APEC is a name that is highly revered in the world of water filtration, and this is especially true for the company’s top tier model. It produces supreme quality drinking water through its 6-stage reverse osmosis processes.
The APEC unit can filter 75 gallons of water per day using a 6-stage system that removes up to 99% bacteria, viruses, cysts, organics, heavy metals, chemicals, and more. The filtration cartridges are made in the USA and work to remineralize your home’s drinking water with calcium. By adding calcium minerals back into the water, the final product is also alkalized and completely tasteless/odorless.
The main reason that this is the ideal solution for improving home drinking water is put into clear terms by the APEC company:
“Some alkaline RO systems may claim to add various minerals back into the water. However, their mineral formulations are often from unknown and uncertified sources that can lead to potential health risks….APEC ROES-PH75 provides only the simple and essential alkaline water without any additives added to ensure your health.”
In the box, you’ll receive all the parts and pieces necessary for assembly and installation, including a 100% lead-free designer faucet, FDA-certified JG food grade tubing, and high-quality leak-free quick-connect fittings that require no extra lock clips to seal leak. Just like any RO system, this one can be tricky to install, so you may want to hire an expert.
Pros
Cons
5. APEC WFS-1000
Best 3 Stage Under Sink Water Filter
Minimum Water Pressure | 20 PSI |
Water Waste/Pure Water Ratio | No Waste |
Contaminants Removed | Chemicals, Tastes, Odors, VOCs, and More |
Filtration Media | Mechanical |
Filter Life | 1 Year |
Warranty | 1 Year |
Another top choice from APEX, the company's WFS-1000 filtration system is the best 3-stage under sink water filter. Many people feel that 3 stages are not enough to adequately filter their water, but this is not the case with the WFS-1000. Home Depot says that
“the system provides a continuous on demand supply of quality filtered water directly to the provided water dispenser.”
Reviewers of this model say that the installation for this 3-stage filtration unit is easier than ever. The system comes with everything required for assembly and installation, including a 100% lead-free chrome faucet, plus FDA-certified JG food grade tubing to provide pure drinking water for the entire family. When installed properly, this system is guaranteed to remove chemicals, tastes, and odors that should not be present in your drinking water.
This APEC was designed and constructed in the USA to be waste-free. That means there is no water lost to waste whatsoever since it doesn’t require regular filter flushing, so all water going into the filtration unit ends up in your cup. This is an amazing feature if you’re looking for a highly Earth-friendly model that not only cuts down on plastic bottles but has no waste output whatsoever.
As far as the 3 stages of filtration, here’s what you need to know about the WSF-1000. Stage 1 is all about filtering out sediments, dust particles, and rust. Stage 2 works to get rid of unpleasant odors and tastes with the help of activated carbon filtration. The third stage uses another activated carbon block to remove chemicals further and enhance your water's purity even more. This 3-stage method has been tried and proven, and you can expect each of the 3 filters to last for a full year.
Pros
Cons
6. Filtrete
Best Budget Model
Minimum Water Pressure | 25 PSI |
Water Waste/Pure Water Ratio | No Waste |
Contaminants Removed | Microbial Cysts, Chlorine, Sand, Soil, Silt, Rust, and Sediment |
Filtration Media | Mechanical |
Filter Life | 6 Months |
Warranty | No Warranty |
The best under sink water filter 2019 for residential homeowners on a budget is the Filtrete Quick Change Water Filtration System. Not only is the initial cost low, but so is the cost of the replacement filters, which are recommended to be changed every 6 months. When you come across a filtration system that requires biannual filter changes, looking at the cost of replacement filters is more important than ever, but in this case, there is no need to worry about high filter costs.
Aside from the low cost, another perk of choosing the Filtrete is that installation is a simple process. Installation takes less than 30 minutes and allows you to maintain full water flow on your existing kitchen faucet. There are 3 unique Filtrete systems to choose from - Advanced, Maximum, and Standard. For optimal filtration that includes lead removal, we recommend maximum filtration, which is NSF certified for Standards 53 and 42.
According to these standards, the NSF says that
“filters are certified to reduce a contaminant with a health effect. Health effects are set in this standard as regulated by the U.S. Environmental Protection Agency (EPA) and Health Canada. Both standards 42 and 53 cover adsorption/filtration, which is a process that occurs when liquid, gas, or dissolved/suspended matter adheres to the surface of, or in the pores of, an adsorbent media."
You can count on the Filtrete doing these things and more with its official certifications.
Pros
Cons
7. AO Smith
Best Under Sink Water Filter Reverse Osmosis
Minimum Water Pressure | 25 PSI |
Water Waste/Pure Water Ratio | No Waste |
Contaminants Removed | Lead, Fluoride, Chromium, Mercury, Asbestos, Pesticides, Pharmaceuticals, and Chlorine |
Filtration Media | Mechanical |
Filter Life | 12 Months (6 Months for Microbial Boost) |
Warranty | 2 Years |
Looking for the best under sink water filter system that is as heavy-duty as it gets? Consider the AO Smith 4-Stage RO Filter System with Microbial Boost. This model also comes in a 2-stage option, but the 4-stage is the most effective when it comes to reducing contaminants and creating only the purest drinking water for the home.
This system uses maximum filtration to remove up to 99% of nearly 100 harmful contaminants that are common in both municipal and well water. Just to name a few, the AO Smith works to minimize lead, fluoride, chromium, mercury, asbestos, pesticides, pharmaceuticals, and chlorine. The presence of any of these impurities is worrisome, but the AO Smith can wash those worries away.
Aside from reverse osmosis filtration, the AO Smith goes through a remineralization process as well as a microbial filtration phase. During these processes, the system returns the healthy minerals lost in the RO phase, including calcium, magnesium, and potassium. While doing these, it works even further to remove harmful bacteria with the microbial boost feature.
Not only does the AO Smith meet the same NSF 42 and 53 standards we mentioned before, but it goes above in beyond with additional certifications, including 58, 401, and P473. It’s even IAPMO certified and tested to NSF/ANSI standard P231, which is difficult to find in a residential filtration system. Every purchase comes with the first set of filters and every required for assembly, including a stunning brushed nickel faucet for dispensing the filtered water.
Pros
Cons
8. Aquasana AQ-5300+.55
Best Under Sink Water Filter for Well Water
Minimum Water Pressure | 25 PSI |
Water Waste/Pure Water Ratio | 3:1 |
Contaminants Removed | Lead, Mercury, Asbestos, Pesticides, Pharmaceuticals, Chlorine, Chloramine, and More |
Filtration Media | Mechanical |
Filter Life | 6 Months |
Warranty | 1 Year |
There are many filters out there that are not compatible with well water. If you’re someone who does not have access to a municipal water source and you use well water instead, you’ll want to find the best under sink water filter system for well water. There’s no question that the best filtration system for producing sparkling clean water from a well is the Aquasana AQ-5300+.55.
Although this system does not reduce total dissolved solids (TDS), it does help to de-contaminate well water by removing up to 99% of 77 contaminants. The cost-efficient and longlasting design mean that you’ll be using this filtration system for years to come, but you will need to replace the filter cartridges every 6 months or so.
The Aquasana has a high flow rate, which is one feature that so many reviewers find attractive. It has the power to filter half a gallon of water per minute, so you’ll never have to wait around for clean drinking water to be dispensed. And best of all is that this is a highly economical filtration unit; once you break it down, each gallon of filtered water created by the Aquasana costs less than 10 cents.
Another thing that so many people love about the Aquasana is the attractive faucet that comes along with the filtration unit. You have 3 options for faucet finishes, including brushed nickel, oil-rubbed bronze, and chrome. If you have stainless steel appliances in your kitchen, the chrome faucet finish is a great choice.
Pros
Cons
How Under Sink Water Filters Work
The method in which an under sink water filter operates depends on the type. There are 3 main types - we'll cover those next - and each one operates uniquely. However, there is a general process for how an under sink water filter works, and it all starts installing the filter beneath the sink space.
Installation involves using a diverter to divert the water from the main cold water pipe to the filtration system. This is done using a connection hose that is almost always made from short plastic tubing. Once this connection is made, water will be diverted from the central line into the filtration device.
There is a separate faucet that is mounted on the sink that the filtered water will be delivered to. Since an under sink water filter must send the water up after the filtration process, there is a need for pressure in this type of system. An under sink water filter is a bit more complicated than one that is mounted above the countertop, but the perk is that it is entirely out of sight.
Under Sink vs Countertop Filters
There's no doubt that an under-sink filter is more challenging to install than one that sits on the countertop. The same goes for under-mounted kitchen sinks and ones that are mounted on top of the countertop space. But even though the installation is more difficult, there are plenty of advantages that come along with choosing an under-sink filter over a countertop design.
Many people prefer the under-sink design sink as it is completely hidden from view. This means no messy hoses and no unattractive diverters can be seen. On top of that, under-sink filters are often more effective at filtering out contaminants since they utilize more filtration stages.
Under Sink vs Whole House Filters
With a whole-house water filter, you'll have access to pure water throughout the house, not just within one sink space. Of course, this may seem advantageous at first, but you'll quickly change your mind as soon as you realize the installation costs involved. It goes without saying that you’ll need professional plumbing help - unless you’re an expert yourself.
Under sink water filters have much easier installation steps, they are way easier to maintain, and they are much more affordable. As long as you are OK with just having one point-of-use (usually at the kitchen sink), an under-sink filter is the better choice if you want something hassle-free.
Installing & Replacing Under Sink Water Filters
The steps for how to install an under sink water filter are dependent on the specific model you’ve chosen. Installation varies depending on whether you’ve opted for a conventional, simple, or RO filtration system. For help with installation, you can follow the general steps provided below, but it is still highly recommended that you carefully follow the steps provided by the manufacturer.
Cleaning & Maintenance
Cleaning an under sink water filter is something that should be done once per year, and it’s best to do it when you change out the filter cartridge. The first step is to close the supply line and shut off any valves that flow through the system. Next, drain the filter by opening the faucet, which will also relieve any pressure that is built up in the lines.
After draining, open the filter housing and leave the hatch in an upright position. There are O-rings within this housing unit that should be changed, and this will ensure that no leaking happens over the filter’s lifespan. While the housing hatch is opened, switch out the filter cartridges with new ones from the same manufacturer.
Following this, sanitize the filter using a recommended sanitizer by adding about one teaspoon to the lower end of the filter sump.
Quora says that to thoroughly clean, you should “put the two ends of the sump pipes to the faucets with the sanitizing solutions inside them.”
Then, open the water supply before removing them and letting everything dry. The last step is to put all of the hoses and connections back in the original place, then activate the new cartridges by running water for 5-10 minutes.
People Also Ask (FAQs)
What is remineralization?
Remineralization is the process of adding minerals back into filtered water. During filtration, most of the healthy minerals are filtered out, so it’s a good idea to choose a unit that has a stage that is solely focused on remineralization.
How much do under sink water filters normally cost?
The cost of an under sink water filter depends on many things, like filtration stages and the filtering media. You could be spending anywhere between $100 to $600. No matter how much you spend initially, be sure to factor in the average annual cost of replacement filters.
What are the stages of purification in Reverse Osmosis systems?
There are generally 5 stages of filtration with RO systems, including sediment removal, activated carbon filtration, reverse osmosis stage, tank storage, and final activated carbon filtration.
What under sink water filter connections are required?
This depends on the specific unit and its filtration process. The good news is that you won’t have to worry about purchasing the tubing and connection separately since nearly all under sink filters come with all the required parts and pieces from the manufacturer.
What do you do if you’re under sink water filter has low pressure?
A few things could cause low pressure, but a buildup within the filter itself often causes it. This is typically as simple as changing out the filter for a new one, and as long as you keep up with replacing the filter cartridges, you should not have a problem with low pressure. However, other causes of low pressure are more difficult to fix, such as a lack of pressure in the tank or a kink in the waterline.
What is Alkalization?
Alkalization is “a process that lowers the amount of acid in a solution.”
More specifically, it is the process of raising the pH to make the solution more alkaline (and less acidic). The EPA requires tap water to have a pH level between 6.5 and 8.5.
In most cases, water is on the low end of this value, but studies are showing that there may be some health benefits to drinking water that has a higher pH. Under-sink filters that alkalize your drinking water can often raise the pH level of your water to 9 or above by adding minerals.
Conclusion
Even though it comes with a high price tag, our top pick remains to be the Home Master TMAFC-ERP.
We love it for so many reasons, including its high filtering capacity and the fact that it utilizes 7 stages of filtration to produce pure drinking water.
But the thing we love most is that it produces very little wastewater compared to other RO filtration systems on the market.
Matt is a freelance writer, English graduate, & keen traveler from the UK. As a specialist plumbing expert, he enjoys writing about everything there has to do with at-home plumbing products & related problems. When he isn’t writing, he’s usually drinking coffee or planning his next adventure. In his spare time, he also runs his own blog all about digital nomad life.