iSpring CU-A4 4-Stage Under-Sink Water Filter Review 2022

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This is our review of the iSpring CU-A4 4-Stage Under-Sink Water Filter System.

Looking for an under-sink water filter for your household is not an easy task, but we are here for you! We put into practice our accumulated knowledge of water filtration systems to perform an extensive review of the iSpring CU-A4 4-Stage Under-Sink Water Filter to help you decide if this system suits your needs.

The iSpring CU-A4 is a good choice for a conventional under-sink water filtration system for several reasons. Through a 4-stage filtration process, it can remove up to 99% of 700+ water contaminants without removing healthy minerals, ensuring that it will have clean and healthy water available.

In this comprehensive iSpring CU-A4 4-Stage Under-Sink Water Filter review, we will analyze the filtration capabilities, the system capacity & longevity, its flow rate, the installation & maintenance process, and discuss customer reviews and potential alternatives for this under-sink water filter system.

Let’s get started!

iSpring CU-A4 4-Stage Under-Sink Water Filter Overview

The iSpring CU-A4 4-Stage Under Sink Water Filter, as the name suggests, combines a 4-stage process to filter different types of contaminants, making it capable to reduce up to 99% of some harmful contaminants like chlorine, heavy metals, VOCs, and much more.

This system comes with color-coded tubes and easy-to-connect fittings to make the installation process easy and straightforward so that you don’t have to spend several hours installing it.

The iSpring CU-A4 4-Stage Under Sink Water Filter comes with a well-designed chrome faucet that fits well in any kitchen sink, that is used to get the filtered water. All of the materials used for the faucet and water filter are tested to comply with the safety and water quality standards.

Additional topics to consider are that this under-sink water filter comes with a 1-year limited warranty, and the iSpring support is well recognized and the US-based support team is capable of solving the customer’s issues.

iSpring CU-A4 4-Stage Under-Sink Water Filter Filtration Capabilities

The iSpring CU-A4 Under-Sink Water Filter is able to remove up to 99% of more than 700 contaminants that we can find in the water, such as chlorine, lead, arsenic, VOCs, asbestos, PFOS/PFOA, bad taste & odors, and much more. And this device not only filters these harmful contaminants, but it does without removing healthy minerals like calcium and magnesium from the water, providing clean and tasty water in this way.

The reduction of more than 700 contaminants is achieved through a 4-stage filtration process that consists of the following phases:

  • Stage #1: PP sediment 5-micron filter, which removes larger particles like sediments, sand, rust, slit, etc.
  • Stage #2: Ultra-filtration semi-permeable membrane, which is capable of removing smaller particles
  • Stage #3: Kinetic Degradation Fluxion (KDF) with activated carbon filter, which removes heavy metals, chloramine, and more
  • Stage #4: Post Activated Carbon ultra-micron filter, which removes chemicals, VOCs, chlorine, bad taste & odors

While it is important to note that the iSpring CU-A4 4-stage under-sink water filter is not NSF certified, iSpring claims that this system was independently tested against the NSF and ANSI water quality and safety standards.

But there are a few contaminants that this under-sink water system can’t remove, and you should be aware in case you need to deal with them. The iSpring CU-A4 4-stage water filter cannot remove fluoride, FPAS, or viruses – if you need to deal with these contaminants it will be better to get a Reverse Osmosis system.

iSpring CU-A4 4-Stage Under-Sink Water Filter Capacity & Longevity

As you can check in the figure below, each of the 4 filters will have different capacities and longevity, but the recommendation is to replace each filter cartridge every 6 to 12 months, depending on usage, except the UF filter which should last for 12 months.

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The filters should have a capacity to filter around 1.100 gallons of water on average, so that is the reason the recommendation is to replace them every 6 to 12 months, for an average-sized family. 

The filtration capacity also depends on the concentration of contaminants, so if your water source is heavily polluted, the filters will have to remove more contaminants and will last less than expected. The opposite is true if your water source is not heavily polluted.

iSpring CU-A4 4-Stage Under-Sink Water Filter Flow Rate

The flow rate is an important factor to consider when you buy an under-sink water filter for your household because it will indicate how much time it will take to filter the amount of water that you need.

The iSpring CU-A4 4-Stage Under-Sink Water Filter has a flow rate between 0.5 to 0.9 GPM  (gallons per minute), which is a good flow rate and that means that you won’t have to wait long to fill a glass of water.

iSpring CU-A4 4-Stage Under-Sink Water Filter Installation & Maintenance

Installing a conventional under sink water filter is not as simple as installing other water filter types, but is not terribly difficult if you like DIY tasks. If you are not a fan of this type of activity, you can always call a plumber to install the system for you.

The iSpring CU-A4 4-Stage Under-Sink Water Filter comes with color-coded tubes and push-to-connect fittings which makes the installation process easier than normal.

Regarding maintenance of this device you only need to change the filters as recommended by the manufacturer. And this process is straightforward as there is no need to disconnect the filter, you only need to twist on and off the filter cartridges to replace the old filter with the new one.

iSpring CU-A4 4-Stage Under-Sink Water Filter Reviews

On Amazon website the iSpring CU-A4 4-Stage under-sink water filter has an average rating of 4.4 stars with more than 40 reviews.

Of those reviews, mostly are positive, with 85%+ being 4 or 5-stars reviews, showing that the customers are happy with the device.

If we analyze the reviews closely it is possible to notice that some customers complained about oil after the installation of the device, but other customers explained that it was there to facilitate the installation, and you just need to flush a few gallons of water after the installation.

iSpring CU-A4 4-Stage Under-Sink Water Filter Alternatives

If the iSpring CU-A4 4-Stage under-sink water filter system isn’t the ideal solution for your household, there are other alternatives that you can consider.

Waterdrop G3 Reverse Osmosis Under-Sink Water Filter

A great alternative is the Waterdrop G3 Reverse Osmosis Under-Sink Water Filter system.

This is one of the best Reverse Osmosis systems on the market, and it is installed under the sink. This tankless NSF-certified system removes up to 99% of the water contaminants and comes packed with several smart features like a TDS meter or a filter life indicator in-built on a designer faucet.

Note: You can use our code WFPG3 on Waterdrop to save $55

Aquasana AQ-5300 Under-Sink Water Filter

If you prefer a conventional under-sink water filter, the Aquasana AQ-5300 is a good option.

This device comes with several NSF certifications, reduces up to 99% of 77 common water contaminants through a 3-stage filtration process, and provides good water flow, and an easy installation.

CuZn UC-200 Under-Sink Water Filter

Another nice alternative is the CuZn UC-200 under-sink water filter.

This simple under sink water filter has an amazing longevity of 5 years or 50.000 gallons of filtered water, can be installed in 5 minutes, and removes most of the contaminants found in municipal water through a 3-stage filtration system.

Our Verdict

We recommend the iSpring CU-A4 4-Stage Under-Sink Water Filter system, as it was one of our choices for the best Under Sink Water Filters.

This under-sink water filter reduces up to 99% of more than hundreds of water contaminants, uses a 4-stage filtration process, and can be easily installed & maintained.