6 Best Under Sink Alkaline Water Filter Systems | Reviews 2023

Author: Jason Hollow - Published: 2022/04/12 - Updated: 2023/01/05

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Alkaline under sink water filters are your best buddy if you like the idea of alkaline, filtered drinking water supplied to your kitchen faucet 24/7.

A good system not only removes harmful contaminants from your water supply but also increases water pH and enhances the mineral content for added health benefits.

What’s more, purchase, hookup and maintenance should be affordable and suited for do-it-yourselfers. Add ease of use and you get the perfect alkaline water filter.

So, here is our collection of the 6 best under sink alkaline water filters. Enjoy!


Best Under Sink Alkaline Water Filters – Top Picks

ProductsSpecs & FeaturesWhere to Buy
Best Overall
Crystal Quest Alkaline Under Sink Water Filter System Crystal Quest Alkaline Under Sink Water Filter System

Crystal Quest Alkaline


  • Price: $
  • Water: 0.5 Gallons Per Minute
  • Filter Life: 1-5 Years
  • Water pH: Alkaline
  • Best For: Tap and Well Water

Or read our review

#1 for RO Water
US Water Systems All American 6-Stage Alkaline Reverse Osmosis System US Water Systems All American 6-Stage Alkaline Reverse Osmosis System

USWS All American RO


  • Price: $$$
  • Water: 50-100 Gallons Per Day
  • Filter Life: 6-24 Months
  • Water pH: 8.5-10.0
  • Best For: Alkaline RO Water

Or read our review

#1 Tankless RO
Frizzlife Tankless Reverse Osmosis System with Alkaline Remineralization – PD600-TAM3 Frizzlife Tankless Reverse Osmosis System with Alkaline Remineralization – PD600-TAM3

Frizzlife PD600-TAM3

  • Price: $$$
  • Water: 0.41 Gallons Per Minute
  • Filter Life: 1-2 Years
  • Water pH: >7.5
  • Best For: Alkaline RO Water

Or read our review

Best Under Sink Alkaline Water Filter Reviews

The order of the following under sink alkaline water filter reviews is deliberate. Our favorite products are at the top.

1. Best Overall: Crystal Quest Alkaline Under Sink Water Filter System

The Crystal Quest is the best under sink alkaline water filter for those of us looking for a regular model.

The main reason for this is how it makes use of a multitude of filter media to allow for a wider scope when removing contaminants. Along with additional ionizing media, this will increase the amount of minerals in your water and also your water’s alkalinity, leaving you with alkaline-filtered drinking water with a superb, clean taste!

Crystal Quest Alkaline Under Sink Water Filter System


See More Product Images at crystalquest.com

Main Specs

  • Price: $
  • Filter type: Standard
  • Filter stages: 3
  • Flow rate: 0.5 gallons per minute
  • Filtering capacity: 1-5 Years
  • Estimated annual filter replacement cost: $50-100
  • Minerals: Calcium and magnesium carbonates
  • Best For: The Crystal Quest is best for overall under sink alkaline water filtration.


  • The filter process has 3 important stages:
    • The 5-micron carbon block filter will find and trap sediment, silt, dirt and sand. Chemicals will then be absorbed, such as industrial strength solvents, pesticides and volatile organic compounds. Disinfection products and chlorine will also be targeted.
    • A blend of filter media (ion exchange resin, two types of KDF and granular activated carbon[1] as well as catalytic carbon) supplied by the SMART filter cartridge will vastly reduce or remove various contaminating elements in your water, whether it’s lead, chlorine (99.9%) or pesticides.
    • Healthy and beneficial minerals such as magnesium carbonates and natural calcium are added to the water thanks to the alkalizing water filter, increasing pH levels and water alkalinity.
  • The taste of your water supply will be significantly improved.
  • A flow rate of 0.5 gpm.
  • Maintenance of the filter system is simple! The alkaline filter and the carbon block will last for up to 12 to 18 months, and the SMART filter cartridge will last for around 5 years.
  • The overall cost is an estimated $50-$100 annually, a superb price for what you get!
  • Overall it’s easy to use and simple to install. Depending on the plumbing of your home or building, you can choose between copper tubing (saddle valve) or flex tubing (T-valve).
  • The faucet and all the tools you’ll need to install the system are included.


  • There are no NSF certifications for this product.
  • The 1 year warranty will be void if a licensed professional or plumber does not install the system.

2. Best RO: US Water Systems All American 6-Stage Alkaline Reverse Osmosis System

The US Water Systems All American 6-Stage Alkaline Reverse Osmosis System is another fantastic choice for an under sink alkaline water filter, and one of the best you can buy in 2023.

Outstanding filtration and a build of extremely high standard provide clean, fresh-tasting drinking water, while the livation hydration technology increases the quality of the water by adding beneficial minerals and increasing the pH to a range of 8.5 to 10.0, a superb alkaline level.[2]

US Water Systems All American 6-Stage Alkaline Reverse Osmosis System


See More Product Images at uswatersystems.com

Main Specs

  • Price: $$$
  • Filter type: Reverse osmosis
  • Filter stages: 6
  • Water production: 50-100 gpd
  • Filtering capacity: 6-24 months
  • Estimated annual filter replacement cost: $150-250
  • Water pH: 8.5-10.0
  • Minerals: Calcium, potassium, magnesium
  • Best For: The USWS 6-Stage is ideal for alkaline RO water.

US Water Systems All American 6-Stage Alkaline Reverse Osmosis System a


  • The filter enhances your water through 6 stages:
    • Rust, sand and other types of dirt are removed by the 5-micron sediment filter, which helps avoid clogging in the subsequent filter stages.
    • Chlorine, odors and unwanted tastes are removed by the carbon block pre-filter, which also filters out chemicals.
    • Chloramine is targeted by the special 1-micron carbon block, as well as cysts and lead.
    • At this stage, a membrane, called a reverse osmosis membrane, purifies the water of any other contaminants. These can include fluoride (98%), mercury (98%), bacteria (95%), arsenic (95%) and nitrate (89%).
    • The special livation hydration chamber contains ceramic balls that emit magnesium, potassium and calcium whilst increasing pH of the water and lowering the potential for oxidation reduction. This process helps your body absorb the water, allowing for a healthier immune system.
    • Finally, any remaining unfavorable tastes are removed for optimum clean drinking water.
  • The system provides the highest overall quality as it is 100% made in America!
  • Installation of this under sink alkaline water filter is very easy! This is thanks to components such as:
    • Teflon Tape.
    • An easy to read instruction manual.
    • Filters and color-coded tubing.
    • Quick connect fittings.
  • All materials are 100% free of BPA, and are also NSF + FDA[3] compliant.
  • Sanitizing solution and a syringe are included to help with sanitizing the system during installation, and also when changing the filters.
  • To measure the quality of the water, a free TDS meter is also included.
  • Clean water is stored in a 4.5 gallon tank, so you’ll have plenty of reserves for the future.
  • 4 faucet designs can be chosen from.
    • Brushed chrome.
    • Brushed nickel.
    • Stainless steel.
    • Chrome.
  • O-rings are used to ensure a perfect seal on all the filter elements, which keeps contaminated water from getting through the filters and affecting the clean water.
  • Depending on how much clean water you require and how quickly you require it, you can choose between 2 different membranes with varying daily filtration capacities.
  • There is also the option for a non-electric permeate pump which can increase the water pressure. This can be beneficial due to the following:
    • Increases water quality yet again.
    • Filtration speed becomes twice as fast.
    • There is higher water pressure at the RO dispenser.
    • Less wastewater goes down the drain (clean-to-waste water ratio reduced by like 80%).
  • USWS customer service is top rated!
  • The water filter system has a warranty of 5 years.
  • Maintenance requirements are minimal.
    • The filters (both pre and post) require a change every 6 to 12 months.
    • The reverse osmosis membrane and the alkaline filter last for at least 2 years.
    • The cost of yearly filter replacement is roughly $150 to $225.


  • As it is American-made and has a warranty of 5 years, the US Water Systems All American 6-Stage Alkaline Reverse Osmosis System is higher in price than other similar models.
  • Certain NSF certifications are missing in regards to rates of contamination reduction.

3. Best Tankless RO: Frizzlife Tankless Reverse Osmosis System with Alkaline Remineralization – PD600-TAM3

The FrizzLife Tankless Alkaline RO system is a wonderful alternative to the under sink alkaline system from US Water Systems. This reverse osmosis system sets itself apart however with its tank-free design!

Frizzlife Tankless Reverse Osmosis System with Alkaline Remineralization – PD600-TAM3


See More Product Images at frizzlife.com

Main Specs

  • Price: $$$
  • Filter type: Countertop RO
  • Filter stages: 4
  • Flow rate: 0.41 gallons per minute
  • Filtering capacity: 12-24 months
  • Estimated annual filter replacement cost: $100
  • Water pH: >7.5
  • Best For: The Frizzlife PD600-TAM3 system is best for tankless under sink alkaline RO water purification.

Frizzlife Tankless Reverse Osmosis System with Alkaline Remineralization – PD600-TAM3 a


  • The tank-free design saves room in your home or building.
  • Installation is also simple thanks to the tank-free design.
  • Reviews are testament to the great taste of the filtered water!
  • There is a two-in-one filter cartridge (composed of pleated polypropylene and an activated carbon block) which, with the additional semipermeable RO membrane, will remove unpleasant tastes and smells. It can also reduce amounts of lots of unfavorable elements in your water supply, such as:
    • Chlorine
    • Chloramine
    • Chromium 6
    • Radium
    • Cysts
    • Lead
    • Cadmium
    • Fluoride
    • Arsenic
    • PFOS & PFOA
    • TDS
  • Minerals are restored and water is adjusted to a 7.5 pH level thanks to the alkalizing and remineralizing filter.
  • Wastewater levels are kept to a minimum; for every 1.5 gallons of filtered water, 1 gallon is estimated to be wasted. Other standard RO systems cannot match this!
  • There’s a smart panel display that shows information regarding the remaining life left in the filter, as well as output water TDS. It also reminds you when it’s time to change the filters, and monitors water quality round the clock.
  • A fast flow rate of 0.41 gallons per minute is achieved through the high-capacity membrane and internal pump. (In fact, a glass of RO water can be filled in 10 seconds!)
  • A faucet made of stainless steel (with a brushed nickel finish) is also included.
  • The filters are easy to replace, and also last a long time. Stage 1 and stage 3 filters last for up to 12 months, and the membrane remains effective for up to 2 years.
  • The annual cost of replacement is ~$100 USD, which, for the quality of the system, is reasonable.
  • If you are unsatisfied for any reason, Frizzlife offers a refund for any product for up to 30 days after it is purchased.


  • There is no information regarding the warranty of the filter system.
  • NSF testing certificates for the product aren’t available, meaning the rates of contaminant reduction aren’t known.

4. Longest Trial Period: iSpring RCC7AK 6-Stage Alkaline Remineralization Under Sink Reverse Osmosis System

When it comes to contaminant reduction, there aren’t many NSF-certified under sink alkaline water filters. The iSpring RCC7AK is one of them; and while there are a number of great features in this system, there have been some reported problems with it.

iSpring RCC7AK 6-Stage Alkaline Remineralization Under Sink Reverse Osmosis System


See More Product Images at amazon.com

Main Specs

  • Price: $
  • Filter type: Under sink RO
  • Filter stages: 6
  • Water production: 75 gpd
  • Filtering capacity: 0.5-3 years
  • Estimated annual filter replacement cost: $100
  • NSF: 58
  • Minerals: Magnesium, calcium, potassium
  • Best For: The iSpring RCC7AK system is ideal for those wanting the longest money-back guarantee.


  • There are a number of stages that ensure clean, great tasting drinking water with the iSpring system. These included 5 filtration stages, an alkalinization stage and a mineralization stage. They are as follows:
    • Sediment, dust, rust and big particles are all trapped by the polypropylene sediment filter.
    • The 5-micron granular carbon filter will get rid of unwanted smells and tastes in the water by absorbing chemicals such as chlorine.
    • A 5-micron carbon filter block will then reduce any contamination caused specifically by chlorine. Anything else that is dangerous or would otherwise pollute your water is removed also.
    • The reverse osmosis membrane will filter out
      • Viruses and bacteria (over 99%)
      • Protozoa (99%)
      • Asbestos (99%)
      • Iron (98-99%)
      • Nickel (97-99%)
      • Aluminum (97-98%)
      • Lead (96-98%)
      • Mercury (96-98%)
      • Radioactivity (95-98%)
      • Fluoride (94-96%)
      • Pesticides (over 90%)
      • and TDS (95-99%), as stated by the NSF/ANSI standard 58.
    • Any unfavorable tastes and smells are removed by another granular activated carbon filter.
    • PH levels are balanced by the pH filter, also adding calcium, magnesium and potassium for health benefits.
  • For those worried about leaks, there is a leak detector equipped which will sound an alarm whenever moisture is detected underneath the system.
  • The filtration capacity allows for up to 75 gallons of clean water to be filtered every day, enough for even the largest of households.
  • The pre-filters and post-filters will last you up to 6-12 months, and the RO membrane even up to 2 or 3 years. The cost to replace these is $100, which is significantly lower than some of its competitors!
  • There is also a money back guarantee of 1 year with the iSpring model and a 1-year limited manufacturer warranty.
  • The under sink water filter can be installed DIY (an instruction manual is included, as well as helpful videos) and every part comes included.


  • iSpring customer support (based in Georgia) has proven to be unresponsive on occasion.
  • The tank can only hold 2.5 gallons of clean water, which is smaller than some of the other models.
  • Multiple customers have claimed the model will leak repeatedly despite its alarm system, mostly due to parts that are of low quality.
  • Some customers have said they even received parts that were faulty.

5. Best for Lower Budgets: NU Aqua Platinum Series 6 Stage Alkaline System

Sometimes, the most decisive factor when purchasing a new under sink alkaline water filter is the price. For the NU Aqua Platinum Series 6 Stage Alkaline System, its low price is, without a doubt, an excellent selling point.

NU Aqua Platinum Series 6 Stage Alkaline System


See More Product Images at nuaquasystems.com

Main Specs

  • Price: $
  • Filter type: Under sink RO
  • Filter stages: 6
  • Water production: 100 gpd
  • Filtering capacity: 0.5-2 years
  • Estimated annual filter replacement cost: $120-150
  • Best For: The NU Aqua Platinum Series is best for those on low budgets.


  • Particulate matter is trapped by a sediment filter.
  • The GAC (granular activated carbon) helps remove unwanted water color, taste, or smell, as well as harmful contaminants such as pesticides and chlorine.
  • Chlorine, organic chemicals, iron, manganese, VOCs (volatile organic compounds) and crypto & giardia are all filtered by the carbon block filter.
  • Sodium, chromium, copper, arsenic and lead are removed by the semipermeable RO membrane.
  • Bad taste and smell (which may begin in the tank where water is stored) are removed by the carbon post-filter.
  • The alkaline remineralizing filter will add healthy minerals to make the water more alkaline.
  • By using calcite, tourmaline, bio ceramic, ORP balls and maifan, the alkaline remineralization filter improves your body’s immunity and neutralizes acids, helping it to absorb nutrients that it needs. This also increases the amount of oxygen in the blood and can even slow the speed of ageing!
  • You don’t need to wait very long for purified water – the TFC membrane allows for fast water flow with a flow rate of 100 gpd.
  • Also included are:
    • A leak stoppage valve, which ensures leaks won’t affect your home or building.
    • A filter housing spanner.
    • A TDS Meter.
    • A chrome faucet.
  • The multiple filter stages will last anywhere from 6 months until 2 years. Although they cost between $125-$155 to replace, their longevity means you won’t have to pay this often!
  • There is a fantastic, risk free 120-day guarantee for a refund. This means that if you aren’t satisfied after trying the NU Aqua model, you can return the system and receive your money back for 4 months after purchase.
  • For added security, there is a warranty of 5 years.


  • The USWS system has a slightly larger tank than the NU Aqua, which holds 3.2 gallons of clean water.
  • There are no certifications proving the rate of contaminant reduction.
  • Although there are easy to read instructions and a maintenance guide, they could perhaps be improved with more detail. (On the positive side, a plumber is not needed to install the system. If you know your way around your tools, a DIY installation can be performed in a couple of hours!)

6. Best NSF-Certified: Express Water ROALK5D Reverse Osmosis Alkaline Water Filtration System

The final under sink water filtration system in our list is the Express Water ROALK5D model.

Drinking water is alkalinized by employing multiple stages of water filtration, along with various kinds of minerals.

Express Water ROALK5D Reverse Osmosis Alkaline Water Filtration System


See More Product Images at amazon.com

Main Specs

  • Price: $
  • Filter type: Under sink RO
  • Filter stages: 5
  • Flow rate: 0.8 gpm
  • Filtering capacity: 6-12 months
  • Estimated annual filter replacement cost: $100-120
  • NSF: 42, 58, 401
  • Best For: The Express Water ROALK5D is ideal for NSF certified under sink alkaline filtration.


  • It has a filtration process made up of 5 stages. Carbon and sediment pre-filters will initially get rid of chemicals and dirt, and the reverse osmosis membrane follows up by removing salt, heavy metals, radiologicals and other pollutants. The post-filter provides the water with a fresh, clear taste.
  • An additional sixth stage will alkalize the water using up to five kinds of mineral rocks. This will add minerals like beneficial potassium, magnesium and calcium to the water, also adding 20% more oxygen content.
  • Effective removal of up to 158 water contaminants is guaranteed through the NSF standard certifications: 42, 58, & 401.
    • Most pharmaceuticals (over 99%)
    • Most VOCs (over 99.98%)
    • Mercury (99.85%)
    • Fluoride (99.83%)
    • Chloramine (99.68%)
    • Chromium 6 (99.63%)
    • Lead (99.37%)
    • Nitrate (99.26%)
    • Nitrite (98.92%)
    • Chlorine (98.62%)
    • Arsenic (98.15%)
    • Most semi-volatile compounds (over 98%)
  • A 360 degrees chrome swivel faucet is also included.
  • DIY installation can be easily performed thanks to the model’s quick connect system, saving you both time and money.
  • Glasses and tanks will be filled with filtered water quickly with a swift flow rate of 0.8 gpm.
  • If moisture is ever detected underneath the system, the leak detector will close any water flow to ensure maximum protection from leak damage.
  • Every filter included will last for 6 months (while the membrane lasts for 12). These filters are easily changed, and with a replacement cost of $120, it’s quite reasonable for what the system delivers.
  • The system has a warranty of 1 year.


  • Despite the measures taken with the leak detector, there have been some reported instances of leaks taking place.
  • One customer even complained the water had a bitter taste to it after filtration.
  • The storage tank has a capacity of 4 gallons, which is slightly smaller than the tank of the under sink alkaline USWS filtration system.

Systems Comparison Chart

How do the best under sink alkaline water filters perform when directly compared to each other?

System$$$TypeStagesWater FlowFilter CapacityAnnual CostNSF/ANSIWater pHMineralsBest ForDetails
Crystal Quest$Standard30.5 gpm1-5 Years$50-100?Calcium & MagnesiumBest Under Sink Alkaline Water Filter Overall
USWS RO System$$$RO6?6-24 Months$150-2508.5-10.0Calcium, Magnesium, PotassiumBest For Alkaline RO Water
Frizzlife PD600-TAM3$$$RO40.41 gpm1-2 Years$100>7.5?Best Under Sink Alkaline Tankless RO
iSpring RCC7AK$RO6?0.5-3 Years$10058?Magnesium, Calcium, PotassiumBest For Longest Money-Back Guarantee
NU Aqua Platinum Series 6 Stage$RO6?6-24 Months$120-150??Best For Low Budgets
Express Water ROALK5D$RO50.8 gpm6-12 Months$100-12042, 58, 401??Best Under Sink Alkaline Filter with NSF Certifications

Buyer’s Guide – How to Buy an Under Sink Alkaline Water Filter System (+ How We Tested)

When it comes to under sink alkaline water filters, there are lots of different makes and models. Knowing what you need from one can help you narrow down your list of choices when looking to buy.

Regular Systems & Reverse Osmosis Type Systems

First of all, there are two main alkaline under sink water filter types, and they differ from each other. These are:

  1. Regular alkaline filter systems
  2. RO alkaline filter systems

Regular under sink water filter systems remove contaminants using various filter media. This filter media can include granular activated carbon, sediment filter cartridges, KDF, ion exchange resins[4] and carbon blocks. Each of these individual filters is designed to target and remove a particular type of impurity or contaminant in the water supply.

RO under sink filter systems differ slightly; They make use of the same filter media that regular systems do for filtration, but they also utilize something called a semipermeable RO membrane, which works to remove the majority of contaminants.

A reverse osmosis membrane is a bit of a “double edged sword” – not only does it remove harmful impurities in your water, but also any beneficial minerals the water supply may contain. This leads to purified water that is somewhat acidic and lacking in healthy minerals. This then requires a strong alkalizing and remineralizing process of greater power to make up for this, balancing the water alkalinity and its pH.

Regardless of differences, both regular and reverse osmosis under sink alkaline filtration systems will remove contaminants from a water supply, leaving the water safe to drink and with a pleasant taste.

The Filtration

Generally, if a system has a greater number of filtration stages involved in the filtering process, it’s usually more effective. Repeated filtration will lead to a greater number of contaminants being eliminated, and therefore resulting in clean and great tasting drinking water.

There are many types of filters that contribute specific methods of filtration. What you’ll need for your water supply depends on your water’s chemistry – here’s a list of each filter type and what they do:

  • Activated carbon filter – if your water smells or tastes like chlorine, an activated carbon filter removes this, as well as harmful VOCs and chemicals such as pesticides!
  • Sediment filter – any floating, solid particles, regardless of their size (even if they are submicron) will be trapped by depth or surface filters known as sediment filters.
  • Iron filter – If there are significant amounts of iron present in a water supply, there’s no better filter than an iron filter to remove it.
  • KDF – stands for Kinetic Degradation Fluxation, which is a fancy name for a filter that is fantastic at removing heavy metals that are soluble in water, as well as some chemicals.
  • Ion exchange filter media – heavy metals will be eliminated from the water with this filter.
  • RO membrane – membranes that have pores which are extremely small in size – just 0.0001 micron![5] Practically every contaminant, whether it’s a metal, a salt or even a mineral, will be removed by an RO membrane due to their incredibly small pore size.

As well as this, there are various other filter methods on offer, but to really make an informed choice, you should test your water before you purchase in order to understand what elements are in it and what you want removed.

Multiple filter stages are effective at removing contaminants, but they do have a few drawbacks, which include a larger system that takes up more room, maintenance costs that are higher due to more components, and sometimes even lower water flow and pressure.

Flow Rate & Water Pressure

trickling faucet

Many under sink water filtration systems supply filtered and clean drinking water on demand. For this reason, water flow rate and water pressure are of large importance when choosing a filter system. With systems that are tank-free, the speed of filtration must be quick to avoid a long wait for clean water to be supplied! If your water filter takes 30 minutes to fill up one glass of water, you’re not going to stick it for very long.

A flow rate of 0.4 to 0.5 gallons per minute is a good benchmark for a unit with a decent flow of water.

Besides, with RO systems, the filtration process can be more effective and efficient if the output flow rate and water pressure are kept above a certain threshold. This applies to tank-free and tank-based units and improves both the rate of contaminant removal and the clean-to-wastewater ratio.

Oxidation Reduction Potential (ORP) & pH

An alkaline under sink water filter will make water more alkaline by increasing the pH levels of the water. Anything above a 7.0 is considered alkaline. However, an alkaline level between 8.0 or 9.0 is usually an ideal level for most customers. In our humble opinion, a standard filter (not RO) will be most likely to result in this level of alkalinity. (To jog your memory, water purification caused by reverse osmosis will be lower in pH, thus making it less alkaline.)

Water that has alkaline ions will have a value of negative ORP, thus becoming anti-oxidizing by nature which neutralizes any free radicals within the body. It’s believed this can actually help boost immune function!

Many manufacturers are recommended to explain what pH levels their products can attain. For example, the USWS advertises their water filter to deliver a pH of between 8.5 to 10.

NSF/ANSI Standards

NSF/ANSI certification comes up in almost all our reviews of water filtrations systems. These are standards set by the NSF and ANSI to guarantee that a product removes certain contaminants and performs just as advertised. If you want to be sure that your purchased filtration system performs a successful filtering process, this is how you know.

NSF and ANSI standards can also guarantee other important factors, such as safety of materials used. The list of standards are as follows:

  • Standard 42 – the decrease of other water contamination (e.g. anything not related to health), such as chlorine contamination.
  • Standard 53 – contaminant reduction, particularly those contaminants that are EPA regulated due to negative health effects. This includes the likes of VOCs, cysts, some heavy metals, harmful chemicals, and others.
  • Standard 401 – pesticides, herbicides, trace pharmaceuticals as well as other pollutants that are referred to as “emerging compounds“.
  • Standard 58 – chromium, arsenic, nitrates and nitrite, lead and Total Dissolved Solids (TDS) are some of the contaminants that have their minimum reduction rate set with this standard.

Filtration Capacity & Maintenance

Under sink alkaline water filters are largely free of maintenance. You’ll be happy to hear that any alkaline filtering stages won’t make that any different!

Only a small bit of maintenance is involved. The most pertinent is the replacement of filter cartridges; this usually needs to happen every 6 to 12 months.

Depending on their quality, an RO membrane should last for a minimum of 2 years. An alkaline filter generally lasts for 1-2 years.

There are some variables, however. Factors such as water usage and the conditions of your water supply can take up more or less function of these filters and membranes, affecting the time until they need to be replaced.

Replacement can also be easier in some models than others, too. Some filters are designed to simply twist on or off, which can be done quickly without shutting off your water supply. Some other systems require water to be shut off, and this can be very time consuming.


You can save yourself a lot of money by going DIY on your installation. Whether it’s a regular or a reverse osmosis system, an under sink alkaline filter is simple enough to set up with the right tools and instructions.

The only scenario that could make this trickier is if your system comes with a separate faucet instead of featuring an inline design. This would require drilling holes in parts of your kitchen such as the countertop, which definitely adds a bit of extra stress to the situation. You could look up a bit more on this process, or you can ask a professional for help.

There is, however, one definite circumstance in which we do not recommend DIY installation. When a product tells you that its warranty will be void if you install the system without use of a professional plumber, you should contact a plumber to do the work for you. It may cost more, but could potentially save you money in the long run, should anything happen to your system.

Warranty and Cost

The overall cost of an under sink water filter includes not just the system itself, but also any costs incurred during maintenance or purchasing and replacement of filters and cartridges, the latter of which will add up significantly year upon year. For this reason, we recommend paying for the high quality equipment when you first invest in an under sink alkaline water filter, as better made parts will have more longevity.

Warranty for all systems (if the make or brand is reputable) should be one year minimum.

What is an Alkaline Under Sink Water Filter, and How Does it Work?

best under sink alkaline water filters thumbnail

An alkaline under sink water filter is simply a water filter system that removes impurities from your home water supply and adds minerals and ions to it in order to provide you with constant access to clean, alkaline drinking water.

These particular systems are installed under sinks (either in kitchens or in bathrooms) to leave the water clean, safe and most importantly, alkalinized!

Many of these systems incorporate the use of multiple filter stages in order to increase the amount of healthy minerals and the pH of your water. Using two or more filtering also helps targeting many different types of water contaminants.

Do You Need an Alkaline Water Filter?

Alkaline water filters can be used for many reasons, from health benefits to just improving the smell and odor of your water. Here’s a few key reasons why people purchase under sink alkaline water filters:

  1. While your water supply may be clean and safe to drink, it may be a bit too acidic.
  2. When a water supply has an unpleasant or bitter taste, chlorine is usually responsible. Alkaline water filters will not only remove the chlorine from the water to deliver a better taste and smell, but they also add beneficial minerals like calcium and potassium that are good for your health.
  3. A big reason: your water contains many harmful contaminants, whether they are natural components (such as lead or mercury) or chemicals like pesticides. Alkaline water filters remove these dangerous substances from your water supply.
  4. You may just prefer the taste and aesthetics of alkaline water!

Under Counter Alkaline Water Filter – The Pros & Cons

What advantages and disadvantages are there to using an under sink alkaline water filtration system?


Contaminants Reduced

Perhaps the main advantage of alkaline water filters is the reduced water contamination. When you can’t trust governmental and official bodies to improve the quality of your water, adding a protective layer of filtration to your home’s water supply is crucial.

Increased Water pH

Many people are adamant about alleged health benefits that alkalized water brings. These are:

  • Decreased cancer risk
  • Weight loss
  • Anti-aging effects
  • Immune system support
  • Improved hydration
  • Detoxing qualities
  • Healthier skin

Improved Water Taste

Water that has been filtered generally tastes better. Alkalized water is also enriched with beneficial minerals like potassium and magnesium, which adds to the clean, pleasant taste. It can even be compared to drinking water straight from a natural source, like a mountain spring!

Cheaper Than Bottled Water

Millions of people buy bottled water every year in order to avoid drinking regular tap water. Why? Because they know it’s not the cleanest source of water in the world!

However, do you realize that by performing your own filtration, you could save yourself hundreds, perhaps thousands of dollars each year instead of spending it all on bottled water?

That alkaline water filter just sounds even better now, doesn’t it?

Bottles of water

Beneficial Minerals

The added minerals will contribute to your daily intake. If you’re struggling to get more calcium into your diet, an alkaline water filter will provide your water supply with this. It’s estimated that 20% of our overall daily calcium intake should be provided by the water we drink. If your water lacks this, then you won’t be able to get the nutrients you need!

Simple to Use

Under sink alkaline water filters are notoriously easy to access and use. After installation, the only thing you have to do to access clean water is open its dispenser!

As well as that, filter replacement only needs to occur about once a year – there’s very little hassle!


Possible Side Effects

There are some potentially negative side effects to drinking alkaline water all the time. They include:

  • Decreased stomach acidity. This is a problem because stomach acid is required to destroy harmful pathogens and stop them from getting into your bloodstream.
  • Metabolic alkalosis, a quite serious condition that leads to nausea, vomiting, confusion and muscle twitching, is believed to be caused by drinking water that is too alkaline.
  • Irritation of the skin.
  • Gastrointestinal issues.

Increased Cost

Alkaline water filters will use multiple filter stages, meaning the maintenance cost will likely be higher, as well as the overall cost of the system, as opposed to a regular water filter.

Missing Scientific Evidence

Whilst alkaline filters do add minerals to a water supply, there is unfortunately still a lack of proven scientific evidence to back up the beneficial health claims used to advertise them.

Countertop Units vs. Under Sink Alkaline Filters

If you’re wondering about what makes an under sink filter different from a countertop unit, here’s a list of differences and similarities:

1. The Filtering Process

Both types of filter are similar in this aspect. Single stage and multi-stage filters come in both under sink and countertop forms.

2. Filter Replacements

Replacing a filter is similar enough for both countertop and under sink water filters. Both filters are simply opened to allow removal of the used cartridge and replacement with a new one, then closed again.

3. Filtration Capacity

With hundreds of different models available, low quality and high quality filters will exist equally in the world of under sink filters and countertop filters.

4. Size

Size is usually a deciding factor between purchasing an undersink filter over a countertop filter. Whilst countertop water filters usually have a small, compact design enabling them to only take up minimal space on a kitchen counter, under sink water filters are generally bigger as they are designed to be stored in cabinets. With that said, the fact that under sink filters are tucked away in cabinets may be more appealing to people who don’t want their countertops crowded with water filters.

5. Installation

While under sink water filters need a direct plumbing connection to function properly, countertop water filters don’t require installation. This means they can be easily attached to a water tap in just minutes.

Regular Water vs. Filtered Water vs. Alkaline Water

The big 3: so, what are the differences between regular tap water, alkaline water, and filtered water?

Regular water (or ordinary water) is water from a tap or a well that hasn’t been treated. While in many cases it can be fine, it can also be home to many unpleasant contaminants that can harm you (from anything like pesticides to chlorine to lead) and can also just have a bad taste, smell or look dirty!

Generally, alkaline water is a water supply that is deemed to have a pH of 7.0 or over. When we speak of alkaline water though, we also mean water that has healthy properties due to inclusion of healthy minerals.

The consumption of alkaline water is usually associated with benefits we mentioned earlier, such as healthier skin, an improved immune system and even weight loss, thanks to the beneficial minerals included.

Filtered water is the name given to water from a tap or well that has had a layer of filtration carried out to remove impurities. Filtration is performed to get rid of potentially dangerous contaminants that may harm your health, and to also improve the odor and taste of your water supply.

Frequently Asked Questions (FAQ)

FAQ thumbnail

Do alkaline water filters work?

Yes, alkaline water filters do work. Usually, they increase water pH to up to 10.0.

Is filtered water more alkaline?

Filtered water is more alkaline if a filter system uses an alkalinization/remineralization stage. RO-purified water is more acidic than the feed water.

Can I drink alkaline water every day?

You can, but according to various online sources[6] you shouldn’t consume excess amounts of alkaline drinking water.


An under sink alkaline water filter can make a great addition to your home. You just need to install one suited for your water supply. Our first choice is the Crystal Quest. If you prefer an RO-type system, go with the USWS All American 6-Stage. The Frizzlife PD600-TAM3is a great countertop model.

If you have any questions about these or any other under sink alkaline water filtration systems please leave a comment below!

Further Reading


Meet Jason Hollow

Jason Hollow Jason is the founder of Water Masterz and head of content creation. After six years in the industry, he has tremendous knowledge and first-hand experience on all things related to water treatment.

His credo: Not a single American should have to drink unhealthy water at home.

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