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If you want access to filtered water directly from a kitchen or bathroom faucet, the This Old House Reviews Team is here to help. We researched the best under-sink water filters and created a buyer’s guide to help you make an informed purchase. Here are our top water filter recommendations.
Top 5 Under-Sink Water Filters
- Best Filter Life: CuZn Under-Counter Water Filter
- Most User-Friendly: Filtrete Under-Sink Water Filtration System
- Best Design: Express Water Under-Sink Filtration System
- Most Versatile: Waterdrop Under-Sink Water Filter System
- Best Two-Stage Filter: FRIZZLIFE Under-Sink Water Filter
Under-Sink Water Filters Comparison
| Product | Weight | Filter Life | Flow Rate | Warranty |
|---|---|---|---|---|
| CuZn Under-Counter Water Filter | 8 pounds | 5 years | Not listed | 5 years |
| Filtrete Under-Sink Water Filtration System | 3.1 pounds | 6 months | 2.25 GPM | 1 year |
| 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 |
| FRIZZLIFE Under-Sink Water Filter | 5 pounds | 8 months | 2 GPM | Not listed |
| Product | Weight | Filter Life | Flow Rate | Warranty |
Best Filter Life: CuZn Under-Counter Water Filter
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 five years
✘ Doesn’t specify if it has an NSF certification
✘ Not designed to help with hard water
What Customers Are Saying
Satisfied customers were pleased with this product’s easy-to-follow installation instructions. Many said that the filter improved their water by removing its chemical taste and smell. However, unsatisfied customers were skeptical that this under-sink water filter truly filtered their water effectively.
Most User-Friendly: Filtrete Under-Sink Water Filtration System
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
Positive reviews highlighted 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. Negative reviews pointed out that this under-sink water filter caused flooding and had too much pressure.
Best Design: Express Water Under-Sink Filtration 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 noted 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, unhappy customers complained about how difficult it was to find a compatible replacement water filter.
Most Versatile: Waterdrop Under-Sink Water Filter System
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 two years
✔ Uses an activated carbon filter that improves the taste and smell of your water
✔ Replacing the filter only takes three seconds
✘ 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
Customers who were pleased with their purchase thought that this filter was easy to install, with some saying that it 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 that the system stopped filtering after a few months.
Best Two-Stage Filter: FRIZZLIFE Under-Sink 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 two gallons of water per minute
✔ Takes less than three 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 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, not being durable, and not filtering their water effectively.
Buyer’s Guide
When purchasing a water filter, it’s important to consider how its specifications and design impact its performance. Here are three factors to think about as you’re buying an under-sink water filter:
- Filtration process
- Flow rate
- Water pressure
Filtration Process
Most under-sink water filters purify water 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.
Some under-sink water filters use reverse osmosis to filter water. Reverse osmosis filters purify water by using pressure to force the water through a semipermeable membrane. This leaves behind contaminants, preventing them from reaching the purified side. While this is more effective than carbon, you can still get a quality carbon filter, especially since most under-sink water filters use multiple layers of filtration to provide clean drinking water.
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.
Frequently Asked Questions
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.
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 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.
Why Trust The This Old House Reviews Team
This Old House has empowered homeowners for more than four decades with top-notch home improvement content in the form of television programs, print media, and digital content on its website and social media platforms. The This Old House Reviews Team focuses on creating in-depth product and service review content to help inform your purchasing decision for just about any item or resource that you might need for your home. The This Old House Reviews Team has written over 1,000 reviews on products in the home space, from cordless drills to kitchen trash cans, lawn mowers, and dining room decorations.
We recommend products in each review using an intensive research process, spending hours combing through the best available models on Amazon. For a product to make our list of top picks, it must hold a solid sales record on Amazon, have consistently positive customer reviews, and offer unique features, among other factors. After narrowing down our list of recommendations, we conduct additional research and sometimes in-person testing to ensure that the products meet our standards. Once we conclude the research phase, we craft a well-rounded, user-friendly article that includes our recommended products and additional information to help homeowners like you make the right purchase.
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