4 Best Single-Stage Under Sink Water Filters (*Update 2024)
Written by: Alexandra Uta // Expert Fact-Checking: Buddhini Dolapihilla, MBSS // Last Updated: Jan 31, 2024
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Top Pick: What’s the Best Single-Stage Under Sink Water Filter?
The best single-stage under sink water filter in 2024 is the Epic Smart Shield, because it is NSF-tested and certified to remove 70+ contaminants, super easy to connect and maintain, and backed by a satisfaction guarantee and lifetime warranty.
Which single-stage under sink water filter to choose? With the abundance of choices available, buying the perfect system to meet your needs can be quite a challenge.
To help you make the most educated decision, we have reviewed 13+ single-stage under sink water filters currently available. We have invested numerous hours into researching, testing, comparing, and ranking these products. 4 made it on our best-of list…
Contents
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No Time to Read? Check Our List of the Best Single-Stage Under Sink Water Filters!
| Product | Details | |
|---|---|---|
 Best Overall: Epic Smart Shield |
Overall Rating: 4.5/5.0 ⓘRatings based on filtration performance, NSF testing and certifications, filter service life, cost, our testing, user ratings, product warranty and support, and other factors.
Get 20% Off! Use Code: |
Price: $ Type: Inline Filter Life: 651 Gallons NSF: 42, 53, 401 Annual Cost: $115 Read Review: Click Alexa’s Video Review: Click |
 Best for Targeted Filtration: Hydroviv |
Overall Rating: 4.0/5.0 ⓘRatings based on filtration performance, NSF testing and certifications, filter service life, cost, our testing, user ratings, product warranty and support, and other factors.
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Price: $$ Type: Inline Filter Life: 720 Gallons NSF: 42, 53 Annual Cost: ~$230 Read Review: Click |
 Best Against Microbes: ProOne FS10 |
Overall Rating: 4.0/5.0 ⓘRatings based on filtration performance, NSF testing and certifications, filter service life, cost, our testing, user ratings, product warranty and support, and other factors.
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Price: $$$ Type: Inline Filter Life: 1 Year NSF: 42, 53, 401, P231 Annual Cost: ~$200 Read Review: Click |
Single-Stage Under Sink Water Filter Reviews
Our Top Picks
- Epic Smart Shield – Best Overall
- Hydroviv – Best for Targeted Filtration
- ProOne FS10 – Best for Microbes
- Culligan US-EZ Series – Best for Customization
1. Best Overall: Epic Smart Shield Single-Stage Under Sink Water Filter
In our opinion, the best single-stage under sink water filter in 2024 is the Epic Smart Shield by Epic Water Filters. Why? Because it’s tested and certified against official NSF standards to be effective at removing a wide range of contaminants, and it’s affordable.
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Epic Smart Shield Single-Stage Under Sink Water Filter |
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| Price: | $ |
| System Type: | Inline |
| Filter Capacity: | 651 gal |
| NSF Standards: | 42, 53, 401 |
| Annually: | $115 |
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Overall Rating: 4.5/5.0 ⓘRatings based on filtration performance, NSF testing and certifications, filter service life, cost, our testing, user ratings, product warranty and support, and other factors.
Get 20% Off! Use Code: |
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Alexa’s Video Review
Being an integral member of the BOS team, Alexa has ordered and tested the Epic Smart Shield Under Sink Water Filter at home. She shares her hands-on experience of installing and using the system in the video below:
Other Specs
- Model: Epic Smart Shield
- Last Price: $135
- Filter Media/Process: Carbon Block
- Flow Rate: 1.25 gpm
- WxHxD: 4.25″x19.75″x4.5″
- Water Temperature: 33-100 °F
- Water Pressure: 40-120 psi
- Fitting: 3/8″ NPT
- Warranty: Lifetime
Key Features & Pros
- Affordable!
- The entire system is made in the USA.
- Single-stage under sink water filter based on activated carbon block filtration removes over 70 common contaminants from your water.
- NSF-certified reduction: Chlorine taste and odor, chloramine, particulates, turbidity, lead, cysts, asbestos, mercury, VOCs, MTBE, BPA, Ibuprofen, Estrone, Naproxen, Phenytoin, Nonyl phenol, and more.
- NSF-tested: Pseudomonoas Aeruginosa and E. Coli, PFOA/PFOS, radiological elements, microplastics, and more.
- Installation is fast and easy to perform independently, even without any plumbing or DIY experience. Typically takes just 20 minutes or less to complete.
- The system comes with an installation kit containing the necessary connector hoses and feed water adapter.
- Inline design means the system will operate with your existing faucet and cold water supply. An optional dedicated polished chrome faucet is also available for purchase if you wish.
- The average filter capacity is 650 gallons or 12 months of normal use and the annual cost is just $115 – which is on the low side.
- Subscribing to the manufacturer’s auto-ship program will save you an additional 20% on filter replacements.
- The manufacturer is committed to sustainability and will provide you with a filter cartridge free of charge when you send in 3 used ones for recycling.
- Lifetime warranty and return policy on the system.
- Customer service is knowledgeable and responsive.
Cons
- The flow rate of 1.25 gallons per minute is not bad – but may result in a noticeable pressure drop in some cases.
Our Rating
- Filtration Performance: 4.5/5.0
- Filter Life: 4.0/5.0
- Price: 5.0/5.0
- Maintenance Cost: 5.0/5.0
- Overall: 4.5/5.0
Best for
The Epic Smart Shield is the best overall single-stage under sink water filter system. It’s not only effective but also ideal for people on a low budget.
→ Full Epic Smart Shield Review
2. Best for Targeted Filtration: Hydroviv Under Sink Water Filter
Hydroviv single-stage under sink water filters are customized to the quality of your water supply which is an approach that we really like. But there are a few issues. Learn more below!
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Hydroviv Under Sink Water Filter |
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| Price: | $$ |
| System Type: | Inline |
| Filter Capacity: | 720 gal |
| NSF Standards: | 42, 53 |
| Annually: | ~$230 |
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Overall Rating: 4.0/5.0 ⓘRatings based on filtration performance, NSF testing and certifications, filter service life, cost, our testing, user ratings, product warranty and support, and other factors.
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Other Specs
- Model: Hydroviv Under Sink Water Filter
- Last Price: $233.32
- Filter Media/Process: Varies
- Flow Rate: Not Specified
- WxHxD: 6″x14″x6″
- Fitting: 3/8” NPT
- Warranty: 1 Year
Key Features & Pros
- Manufactured in the USA.
- Unlike other companies, Hydroviv uses a tailor-made approach to designing water filter systems. This involves examining your local publicly available water data and assessments, and then designing a filter to specifically target and remove the contaminants that were detected.
- Due to this proprietary design, the specific filter media will differ from one system to another. Depending on what’s used, it may remove arsenic, lead, mercury, chlorine, cysts, chromium 6, trace pharmaceuticals, disinfection byproducts, PFAS, and more.
- Many of Hydroviv’s systems feature NSF certifications 42 and 53.
- As with most inline under sink filter systems, installation is very simple to perform, and can typically be completed in just 15 minutes or less.
- The manufacturer provides detailed installation instructions as well as video.
- Single-stage system design makes these systems incredibly easy to maintain.
- Hydroviv systems typically need a new cartridge replacement every 6 to 12 months (the typical filter capacity is 720 gallons).
- Replacement filters cost $115 – resulting in an annual cost between $115 and $230.
- 30-day satisfaction guarantee.
- One-year limited manufacturer warranty on the entire system.
Cons
- The filter media is not revealed by the manufacturer, so we don’t know precisely what each filter cartridge contains.
- The manufacturer’s tailored approach to designing water filters is compelling, but as it only uses publicly available data, there is a chance the data used is incomplete. It may miss certain contaminants like copper or lead from old pipes.
Our Rating
- Filtration Performance: 4.5/5.0
- Filter Life: 4.5/5.0
- Price: 4.0/5.0
- Maintenance Cost: 4.0/5.0
- Overall: 4.0/5.0
Best for
The Hydroviv Under Sink Water Filter is the best single-stage system for targeted contaminant removal.
→ Full Hydroviv Under Sink Filter Review
3. Best Against Microbes: ProOne FS10 Under Sink Water Filter
If you are dealing with microorganisms in your water supply, then you should definitely check out the ProOne FS10 Under Sink Water Filter which removes bacteria, viruses, and cysts.
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ProOne FS10 Under Sink Water Filter |
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| Price: | $$$ |
| System Type: | Inline |
| Filter Capacity: | 12 Months |
| NSF Standards: | 42, 53, 401, P231 |
| Annually: | ~$200 |
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Overall Rating: 4.0/5.0 ⓘRatings based on filtration performance, NSF testing and certifications, filter service life, cost, our testing, user ratings, product warranty and support, and other factors.
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Other Specs
- Model: PM-FS10
- Last Price: $388.95
- Filter Media/Process: Electro Absorption, Infused Microporous Foam Disks, Catalytic Carbon
- Flow Rate: 1 gpm
- WxHxD: 7.25″x18.5″x7.25″
- Weight: 12 lb.
- Water Temperature: 41-100 °F
- Water Pressure: 20-80 psi
- Fitting: 3/8”
- Warranty: 2-Year Limited
Key Features & Pros
- Single-stage filter system uses a combination of several different filter media to remove a broad range of common contaminants.
- Electro-absorptive media removes submicron-sized particulates, pathogens, as well as trace pharmaceuticals.
- Next come multiple layers of infused porous foam disks.
- Lastly, catalytic GAC (granular activated carbon) removes chlorine/chloramine, foul tastes and odors, and organic chemicals.
- Altogether, the filter stages listed above will reduce or remove over 220 contaminants, including VOCs, fluoride, heavy metals like lead (99.99%), water disinfectants and their disinfection byproducts, SVCs, herbicides and pesticides (99.99%), trace pharmaceuticals, PFOS and PFOA, as well as up to 99.9999% of microbial contaminants.
- The system is independently lab-tested to NSF/ANSI Standards 42, 53, P231, and 401.
- Like other single-stage under sink water filters, installation is very simple.
- Filter wrench, mounting bracket, lead-free fittings, and a 3/8” braided flex hose come included with the installation kit.
- Can either be installed in line with the existing faucet, or using a separate dedicated faucet.
- Can also be used in a two-way fashion with both the sink and refrigerator with an optional ¼-inch T-valve.
- Easy to maintain.
- Filters last about 1 year of normal use and cost $209.95 annually to replace.
- The filter cartridges are standard-sized 4.5” x 10” – so you can replace the existing filter with any other standard-sized filter to cut costs or swap to a different filter media.
- 2-year manufacturer warranty (limited).
- The system uses only BPA-free materials.
Cons
- The manufacturer-recommended flow rate is 0.2 to 1 gpm – which is on the low end, and at 0.2 is too low to be practical. If the independent testing conducted was at these levels, then the contaminant reduction numbers will be inflated due to longer than normal contact time with the filter media. There is no way to verify this currently, so it’s essentially speculation on our part.
- The manufacturer claims that the system is lab-tested to NSF standards, but because there is no official certification, we have no way to ensure these claims are accurate.
Our Rating
- Filtration Performance: 4.0/5.0
- Filter Life: 5.0/5.0
- Price: 4.0/5.0
- Maintenance Cost: 4.5/5.0
- Overall: 4.0/5.0
Best for
The ProOne FS10 is the best option for single-stage under sink microbial filtration.
4. Best for Customization: Culligan US-EZ-1, US-EZ-3, and US-EZ-4
Why are Culligan’s single-stage under sink water filters best for customization? Because the filter cartridges are interchangeable. In other words, you can switch between them if you need more basic/thorough water filtration.
Culligan US-EZ-1 Under Sink Water Filter |
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| Price: | $ |
| System Type: | Dedicated Faucet |
| Filter Capacity: | 500 gal |
| NSF Standards: | 42 |
| Annually: | ~$20 |
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Overall Rating: 3.0/5.0 ⓘRatings based on filtration performance, NSF testing and certifications, filter service life, cost, our testing, user ratings, product warranty and support, and other factors.
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Other Specs
- Model: US-EZ-1, US-EZ-3, US-EZ-4
- Annual Maintenance Cost: ~$20-160
- Filter Media/Process: Carbon-Based
- Flow Rate: 0.5 gpm
- Filtering Capacity: 500-3,000 gal
- WxHxD: 3.5″x11.875-14.325″x3.5″
- Water Temperature: 40-100 °F
- Water Pressure: 30-100 psi
- NSF Certifications: Standard 42, 53, 401
- Warranty: 2 Years
Key Features & Pros
- The system is offered in three different tiers of carbon-based filtration all using a single replaceable filter cartridge.
- US-EZ-1: Basic filter will remove only chlorine and particulates (Class III), NSF-tested and certified.
- US-EZ-3: Advanced filter to remove chlorine, Class 1 particulates, lead, cysts, turbidity, atrazine, and lindane. Certified to NSF standards 42 and 53.
- US-EZ-4: The premium filter will remove chlorine plus chloramine in addition to Class 1 particulates, lead, cysts, mercury, MTBE, VOCs, PFOS/PFOA, turbidity, and several additional contaminants. (NSF certified to Standards 42, 53, and 401).
- A separate lead-free faucet is included.
- Installation is fast and easy, with quick connect fittings as well as detailed installation instructions.
- Installation can be completed on your own – DIY style – without the need to hire a plumber or contractor.
- The twist-on/twist-off filter cartridge design allows you to replace a filter in minutes without having to shut off the main water supply.
- The US-EZ-1 filter will last for about 3,000 gallons or 12 months. This comes to an annual cost of just $20 – one of the lowest of any water filter system.
- The US-EZ-3 filter lasts for about 500 gallons or six months of use. Annual replacement costs come to about $90 – which is still highly affordable and cheaper than many other filter systems.
- The US-EZ-4 filter has the same six-month or 500-gallon filter capacity, but as it costs more, annual costs come to approximately $160 per year – putting it in line with most other systems of this type.
- Backed by a limited 2-year manufacturer warranty.
Cons
- The included faucet quality is somewhat lacking – it’s made of plastic rather than metal except for the spout.
- The flow rate of 0.5 gallons per minute at 60 psi is on the low side and may result in longer than normal wait times.
- Some users reported issues with leaking units related mostly to cracked filter housings and poor-quality plastic connectors.
Our Rating
- Filtration Performance: 4.0/5.0
- Filter Life: 4.0/5.0
- Price: 5.0/5.0
- Maintenance Cost: 4.0/5.0
- Overall: 4.0/5.0
Best for
The Culligan US-EZ-1, US-EZ-3, and US-EZ-4 are the best options for single-stage under sink water filtration where customization is your number one priority.
→ Detailed Culligan US-EZ Series Review
More Reviews:
- Which Are the Best Under Sink Water Filters?
- Best Under Sink Hot and Cold Water Filter
- Best Under Sink Water Filter for Hard Water
- These Are the Top Tankless Under Sink Water Filters We Recommend
- Our Under Sink Carbon Water Filter Top Picks
- We Reviewed the Best Inline Under Sink Water Filters!
- The Best Under Sink Water Filter for Apartments
- List with All Under Sink Water Filters Featured on BOS
Comparison List
(Mobile Hint: Swipe to Scroll)
| Model | Price | System Type | Filtration | Filter Capacity | Water Flow | NSF Standards | Annually | Warranty | Additional Info |
|---|---|---|---|---|---|---|---|---|---|
| Epic Smart Shield | $ | Inline | Activated Carbon Block | 651 gal | 1.25 Gallons Per Minute | 42, 53, 401 | $115 | Lifetime | |
| Hydroviv Under Sink Water Filter | $$ | Inline | Varies | 720 gal | 42, 53 | ~$230 | 1 Year | ||
| ProOne FS10 | $$$ | Inline | Electroabsorption, Infused Microporous Foam Disks, Catalytic Activated Carbon | 12 Months | 1 Gallon Per Minute | 42, 53, 401, P231 | ~$200 | 2 Years (Limited) | |
| Culligan US-EZ-1 | $ | Dedicated Faucet | Activated Carbon | 500 gal | 0.5 Gallons Per Minute | 42 | ~$20 | 2 Years |
Buying Guide: How to Choose the Single-Stage Under Sink Water Filter That’s Best for You
The following are key features worth considering when shopping for a single-stage under sink water filter. They will help you choose the right on for your needs and budget.
The Water Quality
The first step to purchasing any water filter system is determining the water quality you’re dealing with. This is necessary as it allows you to pinpoint the exact contaminants contained in your water rather than guessing.
If your water is supplied by a well, then the best way to determine your water’s quality is by having your water tested. This can be done either by using a home test kit or by having your water professionally analyzed in a lab.
Home test kits are cheap and offer near-instant results but are less accurate than professional testing. Additionally, they can miss certain contaminants as they don’t test for everything. Professional testing, on the other hand, offers highly precise and accurate test results, but costs more and requires sending a sample to a lab and then waiting for results.
If your water is municipally supplied, then you can also consult several publicly available resources like EPA’s Safewater or EWG’s Tap Water Database, which will give you the most recent assessments of your water quality. Keep in mind that even though these resources are very useful, they’re less accurate than professional testing, and can miss things like lead or copper leaching from old plumbing lines.
NSF/ANSI Certifications
NSF/ANSI standards are established by the independent testing and certification organization NSF and the American National Standards Institute.
These standards are the best way as a consumer to be sure your water filter is actually removing the contaminants claimed by the manufacturer.
When it comes to single-stage under sink filter systems, there are a few standards you’ll want to be aware of. Most importantly:
- NSF Standard 42 is the standard for the removal of ‘aesthetic effects’ from water. This refers to chlorine/chloramine, foul taste and odor, and particulates.
- NSF Standard 53 is the standard for the removal of contaminants with ‘health effects’. This includes things like lead and other heavy metals, asbestos, PFAS, VOCs, and certain cysts.
- NSF Standard 401 is the standard relating to the removal of ‘emerging compounds’ from water. This pertains to contaminants with potentially harmful effects like herbicides, pesticides, trace pharmaceuticals, detergents, and other chemical compounds.
Filtration Process
The filtration process refers to the type of filtration technology used. For single-stage under sink systems, this is typically carbon filtration, ion exchange, and/or KDF. We also sometimes find additional processes like electro-absorption.
As mentioned previously, choosing the right filtration process will require testing your water first to determine which contaminants it contains.
Water Flow Rates and Pressure
Flow rates refer to the total capacity at which a system can filter water and is typically measured in gallons per minute (gpm). This is an important figure to pay attention to, as too low a flow rate will result in low water pressure from your faucet.
When it comes to under sink systems, 2 gpm is the typical rate at which a standard kitchen faucet delivers water. A system with a flow rate between 1.5 and 2 gpm is unlikely to cause any noticeable reduction in pressure, while below 1 gpm the reduction becomes noticeable and potentially problematic.
Flow rate is of particular importance when it comes to inline systems, as these systems use your existing kitchen faucet to dispense water. This means whenever you open the cold water on an inline faucet, the system will dispense filtered water.
System Installation
Single-stage under sink water filter systems are generally very straightforward to install – typically taking just 15 minutes or less to complete. This is especially true for inline systems, which don’t require installing a separate faucet.
Systems with a separate faucet require a more complex installation involving drilling a hole through the countertop or sink. Sometimes this can be avoided by repurposing an existing hole for a soap dispenser or water jet.
System Maintenance (Filter Life)
Any single-stage water filter system is typically very easy to maintain, only requiring a single periodic filter cartridge replacement. The replacement interval varies from one system to another and is typically provided by the manufacturer in both gallons and number of months.
Keep in mind that the filter life figure provided is an ideal value and real-life values are often less. The actual filter life will vary based on your usage level as well as the level of contaminants in your water.
Also consider that filters with twist-on/twist-off designs are the easiest to change – taking just seconds to swap filters, while filters with housings are often more difficult to change.
Filter Size
Filter size refers to the system’s physical dimensions. For under sink systems, this can be an important consideration, as sink cabinets are often small.
Make sure that before you buy, you measure the available space.
Money
While single-stage under sink water filters aren’t the costliest type of filter system out there, you’ll still want to be mindful of how much you’re spending. All of the above systems retail in the $50 to $400 range, which is fairly reasonable.
More on Single-Stage Under Sink Water Filters
What Is a Single-Stage Under Sink Water Filter and How Does It Work?
A single-stage under sink water filter is any water filter system with a single filter stage that is installed in an under sink cabinet. These systems are designed to be easy to connect and maintain, with just a single stage to care about.
Additionally, as under sink systems are point-of-use systems, they only filter water coming out of a single faucet – either the main kitchen faucet or a secondary dedicated faucet.
Inline System or Dedicated Faucet?
Perhaps the biggest decision you need to make regarding under sink filters is whether to opt for an inline system or go with a dedicated faucet.
- Inline faucet systems – like the name suggests – are installed in line with the existing cold water supply line and faucet. This makes installation exceptionally simple. Generally, all that’s required is connecting the water inlet and outlet to the system and you’re ready to go. The downside to these systems is that because they connect to your existing faucet, all of the cold water flowing from your faucet will be filtered. This increases the demand on the filter system, resulting in reduced filter lifespan when compared to dedicated faucets. Also, a filter with a low flow rate can make certain tasks like cleaning dishes rather unpleasant.
- Dedicated faucet systems use a separate faucet on your sink to dispense filtered water. This typically requires a more complex installation involving drilling a hole through the sink or countertop. The upside to these systems is they allow you to use your main faucet to dispense unfiltered water for cleaning and other tasks, preserving the lifespan of the filter cartridge.
Who Needs a Single-Stage Under Sink Water Filter?
Single-stage under sink water filters are good options when you want basic water filtration at a reasonable price point. Most of these systems feature some type of carbon media which improves water aesthetics and removes organic chemicals among a few other things. More specialized filters can be used for removing all sorts of heavy metals and other contaminants.
There are also filters for both well water and municipal water available, as well as filters with built-in sediment filtration.
How to Install
As mentioned previously, installing an under sink water filter with a single filter stage is generally very simple, and can typically be completed in 15 minutes or less. Contrast that with under sink reverse osmosis systems or whole house filter systems, which often take hours to install.
Another advantage to single-stage under sink filters – especially inline systems – is that installation can be done without altering your plumbing and then removed when needed. This makes these systems perfect for renters.
The precise steps for installing a single-stage under sink filter differ slightly from one system to another, but the following should give you a general idea:
- Shut off the cold water supply underneath your sink.
- Open the cold water on your kitchen faucet to get rid of any water in your plumbing line.
- Disconnect the cold water supply line from under your sink.
- Use the included mounting hardware to mount the filter system in your under sink cabinet.
- Now, attach the loose cold water line to your system inlet and tighten it.
- Then, attach the system outlet hose to the faucet inlet and tighten until snug.
- At this point, turn the cold water supply back on, open the faucet, and flush the system for several minutes.
System Maintenance
Single-stage under sink water filtration systems are exceptionally easy to maintain. The only task typically required is replacing the filter cartridge when needed. The exact replacement interval will vary from one system to another, so be sure to consult your manufacturer’s recommendations. Additionally, your water usage and the level of contaminants in your water will impact the filter’s lifespan.
To change a filter cartridge, follow these steps:
- Shut off the cold water supply valve under your sink.
- Open the faucet to release any water and pressure in the plumbing lines.
- Remove the filter housing from the unit.
- Remove and discard the old cartridge and then clean out the inside of the filter housing with dish soap and warm water.
- Insert the fresh cartridge into the filter housing.
- Check that the O-rings are intact, apply lubrication, and remount the filter housing to the unit head.
- Turn the cold water supply back on.
When to Change the Filter Cartridge
Consult your manufacturer’s recommendations for a general idea of when to change the filter element. Most require changing every 6 to 12 months, although cases with high levels of sediment or water hardness may require more frequent filter changes.
If your system’s flow rate starts to slow significantly, or you notice a foul taste or odor, there’s a good chance your cartridge is expired and you’ll need to swap it out with a new one.
Advantages of Under Sink Water Filters with a Single Filter Stage
Ease of Installation
One of the biggest advantages of these systems is their ease of installation. Most can be installed completely in 15 minutes or less – even if you have no previous plumbing or DIY knowledge or skills. This is especially true for inline systems, which don’t require installing a separate faucet.
Improved Taste
Most units feature some form of carbon filtration, which effectively removes chlorine taste and odor – one of the biggest contributors to poor-tasting municipal water.
Healthier Water
In addition to improving taste, installing an under sink filter system will result in healthier water with significantly fewer contaminants. Depending on the filter type in question, this can mean up to a 99% reduction in contaminants.
Size
When it comes to water filter systems, single-stage under sink is without a doubt one of the most compact types. As a result, it makes an excellent option when space is at a premium.
If you contrast this with under sink reverse osmosis systems, which typically require a 3.2-gallon storage tank sized approximately 9”x9”x14”, you can see how single-stage systems are preferred for compact spaces.
Cost
When it comes to cost, most single-stage under sink water filters can be purchased for surprisingly little moneys. This makes them excellent options for budget-conscious shoppers.
Versatility
Lastly, single-stage under sink filters – especially inline systems – are highly versatile and can be disconnected and reinstalled as needed. This makes them an ideal choice for renters or anyone who may need to move their filter system in the near future.
Under Sink vs. Countertop Systems
Let’s take a brief look at the differences between under sink and countertop filter systems. Both of these occupy similar price points and use cases, so you may find yourself having to choose between the two.
Filter Process
When it comes to the filtration process, both system types are available with a wide variety of water filters. Carbon, sediment, KDF, ion exchange, and other types are readily available in both system configurations.
Filter Capacity
Once again, there isn’t a significant difference between the two when it comes to filtration capacity. You can find units with both high and low filtration capacity in both types.
Size
When it comes to size, countertop systems tend to be slightly more compact, as they occupy premium real estate on your kitchen countertop. Under sink systems can afford to be slightly larger, as the space in your under sink cabinet is not nearly as important as the space on your countertop.
Installation
Most countertop water filters don’t require any installation at all – while some only require a simple water inlet connection. As mentioned before, single-stage under sink water filters don’t require complex installation either, but it’s nonetheless more hands-on than their countertop cousins.
Price
Both types are available at a wide range of price points, so this isn’t an area of significant difference.
Frequently Asked Questions (FAQ)
- Do single-stage under sink water filters actually work?
Yes, they do work. How good they work depends on their design and filtration process applied, so it really depends on which model you buy. Our tip: Check for NSF certifications when shopping. - Are single-stage under sink water filters better than bottled water?
It depends on the quality of the water filter and the quality of the bottled water. Regardless of single or multi-stage, under sink water filters can be really effective. At the same time, bottle water can be of very high quality, too. Of course, one of the downsides of bottled water is the extremely high cost. - Are all under sink water filters the same?
Far from it! Under sink water filters differ in design and filtration process. Some are more basic and only improve water aesthetics, while others can take on many harmful water contaminants. Which to choose should depend on your water conditions. - How long do under sink water filters with one filter stage last?
Under sink water filters with one filter stage typically last 6 to 12 months.
How We Chose and Tested the Best Single-Stage Under Sink Water Filters (Why Trust Us)
Here is how we picked and evaluated the above single-stage under sink water filters:
- Establishing Criteria: Using our years of expertise and research, we first developed a list of 18 key attributes.
- Initial Selection: Based on that criteria, we compiled an initial list of 13+ filters available online.
- Thorough Evaluation: The actual evaluation process started by examining product manuals, product descriptions, product warranties, and third-party certifications/test data. We also contacted representatives from 2 of the brands (Clearly Filtered and Epic) and posed as potential customers to assess their support level. Remaining products: 7.
- User Feedback Analysis: To ensure the highest quality filters, we thoroughly analyzed user feedback and third-party ratings from various platforms. We carefully filtered out any unreliable or fake reviews.
- Hands-On Testing: We purchased and installed 2 systems (more coming soon) on our water supply, allowing us to gain firsthand experience. We considered factors such as system size, how challenging the installation was, maintenance needs, and the taste and pressure of the filtered water. Each under sink water filter operated for a minimum of 3 weeks.
- Lab Testing: Next, we conducted independent lab testing. This allowed us to assess the real-life contaminant reduction rates of each filter. Each filter was tested for its capability to remove close to different 100 substances. After this rigorous process, we were left with 4 top-performing filters.
- The final step was to analyze the gathered information and structure it, so that it would be easy to comprehend.
It’s important to note that all the information and ratings provided in this review guide are impartial and unbiased. Our content also undergoes professional fact-checking to ensure accuracy. We would like to acknowledge Buddhini Dolapihilla, MBSS, for her valuable contribution in reviewing contamination reduction claims (NSF testing and raw lab data).
About Our Ratings
Our evaluation process for single-stage under sink water filters primarily focuses on the following key factors: Contaminant reduction rates based on NSF data (30%), initial and annual cost (25%), hands-on testing and user opinions (20%), filter capacity (15%), customer service and product warranty (10%).
We’ve rated each filter on a score of 1 to 5, with 5 being the highest rating.
Questions? Ask away!
About the Author Alexandra Uta
Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.