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NU Aqua Tankless 600GPD Reverse Osmosis Review

NU Aqua Efficiency Series Tankless 600GPD Alkaline Remineralization Reverse Osmosis System
The NU Aqua WU-600GPD-ALK-TL 600GPD reverse osmosis water filtration system

NU Aqua Tankless RO Overview

NU Aqua Systems has joined the tankless trend and added the NU Aqua Tankless 600GPD reverse osmosis water filtration system (WU-600GPD-TL) to its already impressive lineup.

We got our hands on one so that we could see how it works, compare it to the competition, and find out why it is one of the best tankless reverse osmosis systems.

Right away, there are a few things that set NU Aqua and this tankless reverse osmosis system apart from competing systems:

Tankless RO System

It is a growing trend to do away the with conventional water storage tank that comes with most undersink reverse osmosis systems. Why?

  1. A tank only holds so much water. When you use it all before the system can refill, you experience a noticeable drop in water pressure. The NU Aqua is hundreds of times faster with an integrated pump and no tank.
  2. Storage tanks take up a lot of space under the sink. By removing the tank, a tankless RO system takes up less than half the space.
  3. There is a possibility of contamination and bacteria growth in water storage tanks that you will never see. Tankless systems may help prevent bacteria and ensure even cleaner filtered water!

High Daily Output

While conventional undersink RO systems can process up to 100 gallons per day (GPD), and competing tankless systems offer 400GPD, the NU Aqua tankless RO system can process 600 GPD with an excellent 2:1 pure water to waste ratio.

While most people won’t filter that much water per day, this number indicates how fast these systems are at producing filtered water. In this case, the integrated pump guarantees fast processing and consistent pressure.

5 Year Warranty

Most competing systems have a 1 year and maybe a 3 year warranty. NU Aqua Systems offers a full 5 year warranty on all reverse osmosis systems and will replace any defective parts in that time.

They also offer a 100% Risk-free 120-day Home Trial. Try their system for 120 days and if you don’t love it, you can return it!

Exclusive Savings – 25% OFF for visitors

System Design

The NU Aqua Tankless RO water filter system includes 4 stages of filtration and nearly every other component in a single box. Compared to conventional RO systems, where everything is exposed, this makes everything much tidier under the sink!

Only the power supply and faucet live outside of the main body and everything is connected with just 5 simple connections – all of which are conveniently located on the rear top of the case.

Inside the system body are:

  • The replaceable water filter cartridges
  • Ultra quiet booster pump
  • Integrated water channel design to prevent leaks
  • “Smart” features that let you know the status of your water and filters

The stages of filtration are:

  • Filter 1
    • Polypropylene filter to remove sediment, rust, and suspended particles
    • Carbon block filter removes chlorine, VOCs, tastes, and odors
  • Filter 2
    • Granular activated carbon filter removes color, odor, chlorine, organic chemicals, and improves taste
  • Filter 3
    • 600GPD Reverse osmosis membrane removes everything else, including: heavy metals, chromium, lead, fluoride, nitrates, salts, and more!
  • Filters 4-8
    • Alkaline remineralization filter increases alkalinity, adds back natural, beneficial minerals, and creates antioxidants

What makes this RO water filter system so “smart?”

The RO faucet has an LED ring that glows blue to let you know everything is working normally or red to let you know that one of your filters needs to be replaced.

The system body also has lights to show filter status and overall system health.

Keep in mind that the system needs power to function and it has a single 110V plug to connect under the sink.


The process of reverse osmosis produces waste water containing the concentrated chemicals filtered out of the water and flushes this water down the drain.

The NU Aqua Tankless reverse osmosis system achieves a very good 2:1 ratio of pure water to waste water. This means that for every two units of pure filtered water produced, one unit of waste water is sent down the drain. 1:1 is usually a good ratio and this is twice as efficient!

RO efficiency is measured by a combination of water pressure, water temperature, and the design of the system.

The integrated booster pump in this system ensures optimal water pressure, regardless of the pressure that comes from your plumbing.

Keep in mind that if you pay for municipal water, a more efficient system will save you money both when the system pulls the water and when the waste water is sent down the drain.

As with any undersink RO system, hard water may also require a water softener in your home.

Ease of Installation

NU Aqua Efficiency Series Tankless 600GPD Reverse Osmosis System Connections
5 simple connections to connect the system

The NU Aqua reverse osmosis systems are designed to be installed under the sink by anyone with rudimentary DIY skills.  A professional plumber is not needed for installation.

The only potentially difficult part of the whole installation is drilling a hole in the sink or countertop for the filtered water faucet. This may not be necessary if a hole already exists for a hand sprayer, soap dispenser, or is available with a blank cover.

The full instructions included with this system are some of the most detailed we’ve seen!

Every step includes a picture and they don’t assume you know anything.

All of the system components are well labeled and easy to find.

NU Aqua also provides lifetime support including 24/7 online support, so you can always contact them if you have questions.

While this is a very complete system, check out our list of the water filter accessories for some items to consider with your new reverse osmosis system.


NU Aqua Efficiency Series Tankless 600GPD Reverse Osmosis System Simple Maintenance
Filter changes are quick an easy with instructions right inside the cover!

Changing the filters in tankless RO systems including this one is FAR easier than changing the filters in conventional undersink RO systems.

The three filter modules on this system simply twist in and out of their own numbered channels on the front of the system, where they are easy to reach. Spring locks ensure a proper installation in under a minute with no leaks or mistakes. No tools are needed!

The NU Aqua Tankless filter replacement schedule is:

  • Filter 1 should be replaced once every 6 months
  • Filter 2 should be replaced once every year
  • The reverse osmosis membrane (Filter 3) should only be replaced only once every 36 months
  • See below for links to buy replacement filters

Remember that a water filtration system is only as good as the health of the filters. Over time, filters collect contaminants that must be removed by replacing them.

NU Aqua Tankless RO System Pros

  • Competitive pricing and excellent value
  • Tankless design is smaller and more efficient
  • 600 gallons of pure water output per day
  • Remineralization stage included
  • Super simple filter maintenance
  • 5 year warranty
  • 100% Risk-free 120-day Home Trial

NU Aqua Tankless RO System Cons

Visit our reviews of the top RO systems to compare the NU Aqua systems with the competition.


NU Aqua Systems has made a very competitive tankless solution that costs less than comparable systems that don’t have a smart faucet.

The smaller, more efficient design is a big plus over conventional RO systems and the setup and maintenance are easy.

Combine the quality of the system with the higher-than-average output and 5 year warranty and you get one of the best tankless RO systems you will find!

Exclusive Savings – 25% OFF for visitors

You may also be interested in:

The most popular accessories for this or any other RO system will help you customize your installation! You can easily connect your refrigerator ice maker, extend a hose, or upgrade your faucet.

NU Aqua Tankless Replacement Filters

You can refer back here to order replacement filters as necessary.  It may help to order your first filter set now so you are ready in six months.

NU Aqua Efficiency Series 600GPD replacement filters: