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If you want access to filtered water directly from your bathroom, kitchen sink, or RV faucets, our Reviews Team is here to help.
In this comprehensive review and buying guide, we evaluate the best under-sink water filters to help you make an informed purchase and improve your water quality. Here are our top picks.
Top 5 Under-Sink Water Filters
- Best Overall: CuZn Under-Counter Water Filter
- Best Reverse Osmosis System: Express Water Under-Sink Filtration System
- Best RV Water Filter: Waterdrop Under-Sink Water Filter System
- Most User-Friendly: Filtrete Under-Sink Water Filtration System
- Best Two-Stage Filter: FRIZZLIFE Under-Sink Water Filter
Compare Top Under-Sink Water Filters
| Product | Weight | Filter Life | Flow Rate | Warranty |
|---|---|---|---|---|
| CuZn Under-Counter Water Filter | 8 pounds | 5 years | 2 GPM | 5 years |
| Express Water Under-Sink Filtration System | 31 pounds | 2 years | 2 GPM | 1 year |
| Waterdrop Under-Sink Water Filter System | 4 pounds | 2 years | 0.75 GPM | 1 year |
| Filtrete Under-Sink Water Filtration System | 3.1 pounds | 6 months | 2.25 GPM | 1 year |
| FRIZZLIFE Under-Sink Water Filter | 5 pounds | 8 months | 2 GPM | Not listed |
| Product | Weight | Filter Life | Flow Rate | Warranty |
Best Under-Sink Water Filter Overall
CuZn Under-Counter Water Filter
- $149.95
- $199.95
- 26% off
Prices taken at time of publishing.
Pros and Cons
✔ Designed to attach to your kitchen sink’s cold water line
✔ Uses a catalytic carbon filter that’s resistant to mold and bacteria growth
✔ Can last up to 5 years
✘ Doesn’t specify if it has an NSF certification
✘ Not designed to help with hard water
What Customers Are Saying
Our team found that numerous satisfied customers were pleased with this product’s easy-to-follow installation instructions. Many said the filter improved their water by removing its chemical taste and smell. However, our team also noticed that some unsatisfied customers were skeptical that this under-sink water filter truly filtered their water effectively.
Best Reverse Osmosis System
Express Water Under-Sink Filtration System
- $163.14
Prices taken at time of publishing.
Pros and Cons
✔ Filters 50 gallons of water per day
✔ Features a detection system that automatically shuts off the filter
✔ Includes on-demand support
✘ Has a higher price point than other under-sink water filters
✘ Some customers found it challenging to find replacement water filters
What Customers Are Saying
Many reviewers we noted said that the instructions they received with their reverse osmosis system made installation easy. Positive reviews also highlighted that the quality of their water was immediately improved. On the other hand, we also saw some unhappy customers that complained about how difficult it was to find a compatible replacement water filter.
Best RV Water Filter
Waterdrop Under-Sink Water Filter System
- $69.99
- $93.9
- 26% off
Prices taken at time of publishing.
Pros and Cons
✔ Filter can last for up to 2 years
✔ Uses an activated carbon filter that improves the water’s taste and smell
✔ Replacing the filter only takes 3seconds
✘ Some customers said the filter stopped working after a few months
✘ Has a low flow rate of 0.75 gallons per minute
What Customers Are Saying
According to our research, customers who were pleased with their purchase thought this filter was easy to install, with some saying only took 10 minutes. Other reviewers noted that the flavor and clarity of their water were significantly improved. Dissatisfied customers pointed out that the water flow was weak, and the system stopped filtering after a few months.
Most User-Friendly Water Filter
Filtrete Under-Sink Water Filtration System
- $40.99
- $59.99
- 32% off
Prices taken at time of publishing.
Pros and Cons
✔ Meets the National Science Foundation (NSF) Standard 42, which proves that it filters out certain types and amounts of contaminants
✔ Coordinates with your existing kitchen faucet
✔ Has a lower price point than some other models
✘ Some customers felt the pressure level was too high
✘ Has a lower filter life than some other models
What Customers Are Saying
We found that numerous positive reviews mentioned how easy this product was to install. Customers also said that it improved the flavor of their water and the flow of their water from their kitchen sink. We also saw some negative reviews that pointed out that this under-sink water filter caused flooding and had too much pressure.
Best Two-Stage Water Filter
FRIZZLIFE Under-Sink Water Filter
- $69.99
- $99.99
- 31% off
Prices taken at time of publishing.
Pros and Cons
✔ Removes contaminants from over 2 gallons of water per minute
✔ Takes less than 3 minutes to install
✔ Reduces levels of carcinogens, mercury, and rust
✘ Some customers said it began leaking shortly after installation
✘ Warranty length not specified
What Customers Are Saying
Positive reviews our team found said that this under-sink water filter was well-packaged and easy to install and immediately improved their water’s flavor. Other reviews noted that its cartridge was easy to replace and reasonably priced. Negative reviews criticized this product for leaking and not being as durable as expected.
Under-Sink Filter Buying Guide
When purchasing a water filter, it’s important to consider how its specifications and design impact its performance. Here are three factors our team thinks are important when buying an under-sink water filter:
- Filtration process
- Flow rate
- Water pressure
Filtration Process
Most under-sink water filters purify the water supply through a carbon filter or reverse osmosis. Models with carbon filters purify water by absorbing contaminants. While carbon filters make under-sink water filters more affordable, they don’t remove all contaminants from well water.
Some under-sink water filters use reverse osmosis to filter water. Reverse osmosis water filters purify water by using pressure to force the water through a semipermeable membrane. This leaves behind volatile organic compounds, pharmaceuticals, and impurities in tap water, such as fluoride, heavy metals, herbicides, pesticides, and chloramine. While this is more effective than carbon, you can still get a quality carbon block filter, especially since most under-sink water filters use multiple layers of filtration to provide clean drinking water while leaving in healthy minerals like potassium, calcium, and magnesium.
Flow Rate
An under-sink water filter’s flow rate is determined by how many gallons of water it can purify per minute. This number varies depending on the filter’s filtration method and size. For example, the FRIZZLIFE Under-Sink Water Filter filters two gallons per minute (GPM), while the more narrow Waterdrop Under-Sink Water Filter System filters 0.75 GPM.
Water Pressure
An under-sink water filter’s water pressure impacts its filtration process, as low water pressure inhibits the filtration process. To ensure that their systems are operating at the proper water pressure, many models include water pressure gauges for easy monitoring.
Tips for Using an Under-Sink Water Filter
Using an under-sink water filter can help improve the quality and taste of your drinking water, but it’s important to understand how to use it properly to maintain water quality. Here are some tips for using an under-sink water filter:
- Shut Off the Water Supply: Before installing or replacing the filter cartridge, shut off the water supply to the filter system. This may involve turning off the water valve under the sink or at the main water supply.
- Flush the System: After installing a new filter cartridge or when first using the system, it’s essential to flush the filter. This helps remove any loose carbon fines or debris from the cartridge. Closely read the manufacturer’s instructions for flushing, which typically involves running water through the system for a specific duration or volume.
- Replace Cartridges Regularly: Under-sink water filters typically have replaceable cartridges that require periodic changing. Check the individual product description to see the recommended schedule for cartridge replacement. Regularly replacing the cartridges ensures that the filter continues to function effectively.
- Monitor Water Flow: It’s important to check the water flow rate after installing the filter. If you notice a significant decrease in water pressure, check the filter system for clogs or other issues. Some filters may require occasional cleaning or maintenance to optimize performance.
- Clean and Maintain the Filter: Periodically clean and maintain the filter system according to the product instructions. This may involve removing and cleaning components, such as the housing or diverter valve, to remove any sediment or build-up.
- Test Water Quality: Consider periodically testing your filtered water to ensure that the filter system is effectively removing contaminants. Home water testing kits or professional water testing services can help you assess the quality of your filtered water.
Undersink Water Filter FAQ
What’s the benefit of an under-sink water filter?
Under-sink water filters simplify water purification by filtering water at its source, removing the need to use water-purifying pitchers and creating whole-house safe drinking water.
How much does an under-sink water filter cost?
The price of an under-sink water filter depends on a number of factors, including its filtration method and size. However, most filtration water systems cost between $50 and $100.
How long does the cartridge in an under-sink water filter last?
Most under-sink water filters require a replacement cartridge every six to eight months of use.
How We Selected the Best Under-Sink Water Filters
To provide our readers with the best recommendations possible, we rely on several key sources of information to help guide our selection process.
Initial Research: Our research process began by generating a list of under-sink filters with a significant number of verified-buyer reviews and an average customer review rating of 4–5 stars. We looked at positive and negative reviews alike, focusing on information from both satisfied and critical buyers.
Expert Insights: Through our years of experience, we’ve learned that listening to what others have to say is key to building accurate, well-rounded articles. To complement our in-house expertise, our team looked at reviews and videos from trusted publications and independent testers, spoke with subject matter experts, and drew insights from reader contributions.
Final Product Selection: We then began fine-tuning our list by replacing older models with the latest versions and eliminating any discontinued models. From there, we pared the list down further by comparing each model’s feature set and selecting the best-in-class options for a variety of buyers, budgets, and scenarios.
Why You Can Trust Us
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Our team focuses on creating in-depth product and service review content. To date, we’ve published over 1,600 reviews on products in the home space, from doorbell cameras and backyard fencing to pool vacuums and snow blowers.
Once we conclude our research, we craft a comprehensive, user-friendly article of recommended products and additional information to help our readers make the right purchase.
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