5 Best Tankless Reverse Osmosis Systems of 2022 [Review]

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5 Best Tankless Reverse Osmosis Systems of 2022 [Review] Image

In this article, I will share with you the best tankless Reverse Osmosis systems available in the market and help you to find the best fit for your home.

Tankless Reverse Osmosis System Review

Tankless RO system offers several advantages over tank-based RO system, such as:

  1. Space-saving – tankless RO systems are compact and occupied less space, which allows them to fit into the kitchen under-sink more easily.
  2. No secondary contamination – tankless RO system will not store water in the tank, taking away the risk of second contamination inside the tank.
  3. Fast water filtration rate – compared to tank-based RO systems which have a water output rate of 50 to 100 GPD, tankless RO systems provide a much higher water output rate at 300 to 800 GPD.
  4. High water efficiency – tankless RO systems can generate up to 3:1 clean water to wastewater ratio, while tank-based RO systems usually have a 1:3 clean water to wastewater ratio.

All these benefits make the tankless Reverse Osmosis system a great alternative to the traditional tank-based Reverse Osmosis system.

The 5 Best Tankless Reverse Osmosis Systems Review

1. Waterdrop G3P800 RO System [Review] – Best Tankless Reverse Osmosis System (Overall)

Highlights:
  • Water Filtration: 7 stages
  • Water Output Rate: 800 GPD
  • Water Efficiency: 3:1
  • Features: Smart faucet, filter life display, real-time TDS monitoring, leak detector
  • Certification: NSF Standard 58 and 372

The Waterdrop G3P800 Reverse Osmosis system took the top spot with its unmatched filtration performance and features.

It is an upgrade of the Waterdrop G3 Tankless RO System with improved filtration performance, water efficiency, and water flow rate.

The three filters: sediment pre-filter, 0.0001-micron RO membrane, and a carbon post-filter, offer 7 stages of water filtration to remove 99% of contaminants in water including TDS.

It also has a UV filter that kills microorganisms including bacteria and viruses, which is lacking from most other tankless Reverse Osmosis systems.

It has the highest clean water to wastewater ratio among the best tankless Reverse Osmosis systems, making it an excellent choice for those who are looking for a RO system with superior water efficiency, filtration performance, and useful features.

The Waterdrop G3P800 is capable to produce 800 gallons of RO water per day, one of the highest in the industry.

The tankless RO system also comes with several useful features such as filter life and real-time TDS displays on the smart faucet, leak detector, and quick filter replacement on the front.

It is also tested and certified by NSF/ANSI against standard 58 and 372.

If you prefer alkaline water, you may purchase a separate remineralization filter as an add-on.

Read our in-depth review of Waterdrop G3P800 RO here.

Check Price on Waterdrop Official Store Now
Waterdrop G3P800 discount code: Apply the code “BRIZG3P800” on the official Waterdrop store to enjoy an exclusive $199 OFF (that’s about 20%)!

The Pros & Cons of Waterdrop G3P800 Tankless RO System

Pros
  • Strong water filtration eliminates 99% of waterborne contaminants.
  • Has a UV filter that kills microorganisms including bacteria and viruses.
  • High water output rate of 800 GPD.
  • High water efficiency with 3:1 pure water to wastewater ratio.
  • Slim body design.
  • Comes with a lead-free smart faucet.
  • Useful features like filter life notification, built-in TDS indicator, leak detector, and quick filter replacement.
  • Quick installation
  • NSF certified against Standard 58 and 372
Cons
  • Expensive

Should You Buy the Waterdrop G3P800 Reverse Osmosis System?

If you are looking for the best performing tankless Reverse Osmosis system in the market, the Waterdrop G3P800 RO System is the perfect fit for you.

Budget Alternative:

If the price of Waterdrop G3P800 is over your budget, then you may consider getting the Waterdrop G3, which is also a powerful tankless RO system but with a lower price.

Waterdrop G3 vs G3P800: Comparison

Model

G3

G3 P800

Flow Rate

400 GPD

800 GPD

Drain Ratio

1:1

3:1

UV Sterilizer

No

Yes

Check Price on Waterdrop Official Store Now
Waterdrop G3 discount code: Apply the code “BRIZG3” on the official Waterdrop store to enjoy an exclusive $55 OFF for the Waterdrop G3!

2. Waterdrop D6 Reverse Osmosis System [Review] – Best for Value

2. Waterdrop D6 RO System [Review] - Best Value Tankless RO System
Highlights:
  • Water Filtration: 5 stages
  • Water Output Rate: 600 GPD
  • Water Efficiency Ratio: 2:1
  • Features: Smart faucet, filter life display, real-time TDS monitoring
  • Certification: NSF Standard 58 and 372

Waterdrop D6 is a compact and modern tankless RO system that features a single 6-stages advanced composite filter that removes over 1,000 contaminants in water.

One filter makes the filter replacement quicker and easier.

Besides, the compact RO system can produce clean RO water at 600 gallons per day with a 2:1 clean water to wastewater ratio.

It also comes with a lead-free smart designer faucet that shows TDS level in real-time and the remaining life of the filter.

Read our in-depth review of Waterdrop D6 RO here.

Check Price on Waterdrop Official Store Now
Waterdrop D6 promo code: Apply the code “BRIZD6” on the official Waterdrop store to enjoy an exclusive $50 OFF!

The Pros & Cons of Waterdrop D6 RO System

Pros
  • Single advanced composite RO filter removes over 1,000+ contaminants.
  • Compact and sleek body design
  • Reasonable price
  • High water production rate of 600 GPD
  • 2:1 pure water to wastewater ratio
  • NSF/ANSI certified against Standard 58 and 372
  • Comes with a smart designer faucet with a filter life indicator and real-time TDS display
Cons
  • Require a separate sediment filter to extend its lifespan.

Should You Buy the Waterdrop D6 RO System?

If you are looking for a great tankless RO system at an affordable price, then the Waterdrop D6 shall fit your bill perfectly. It offers great water filtration and features.


3. Frizzlife PD600 Tankless RO System [Review] – Best for Budget

Frizzlife PD600 RO System [Review] - Best Budget Tankless Reverse Osmosis System Image
Highlights:
  • Water Filtration: 7 stages
  • Water Output Rate: 600 GPD
  • Water Efficiency Ratio: 1.5:1
  • Features: Filter life display, real-time TDS monitoring

The Frizzlife PD600 is the budget option from the list of best tankless RO systems.

The system has 7 stages of water filtration including an alkaline remineralization stage to provide clean alkaline drinking water to your family at a lower cost.

It also has a fast water output rate of 600 gallons per day and a 1.5:1 pure water to wastewater ratio.

Besides, the tankless RO system comes with a smart panel that displays the remaining lifespan of each filter and a real-time TDS meter that monitor the water quality.

It is suitable for families who want a compact tankless RO system with strong water filtration and a fast water output rate without spending too much.

Check Price on Frizzlife Official Store Now

The Pros & Cons of Frizzlife PD600 RO System

Pros
  • Strong 7 stages water filtration
  • Produce alkaline water
  • Compact body
  • Good water efficiency of 1.5:1 pure water to wastewater ratio
  • Smart display panel with a filter lifespan reminder and real-time TDS reading
  • Easy to install and replace filters
  • Reasonable price
Cons
  • No NSF certification
  • May produce noises due to the booster pump

Should You Buy the Frizzlife PD600 RO System?

If you prefer to buy one of the best tankless RO systems in the market at the lowest price, then this RO system is the one you are looking for. It is the cheapest tankless RO system on the list.


4. NU Aqua Efficiency Series Tankless RO System [Review] – Best Purchase Guarantee

4. NU Aqua Efficiency Series Tankless RO System - Best Purchase Guarantee Image
Highlights:
  • Water Filtration: 4 stages
  • Water Output Rate: 600 GPD
  • Water Efficiency Ratio: 2:1
  • Features: Smart faucet with a filter life display

The NU Aqua Efficiency Series is a compact tankless RO system that provides clean water to your home without taking up much space in your kitchen.

The 4 stages of RO water filtration remove 99% of contaminants in water including sediment, VOCs, heavy metals, and more.

The NU Aqua tankless RO system provides 600 GPD water output, which is fast enough to fill up a cup without much waiting.

The system comes with a long lifespan RO membrane that lasts up to 36 months, the GAC filter can last up to 12 months, and the sediment/carbon block filter can last up to 6 months.

It also comes with a smart faucet with a filter life indicator.

The tankless RO system produces clean RO water at a 2:1 clean water to wastewater ratio.

Its short and compact body allows it to fit easily under the kitchen sink.

120-day trial period to test out the system at the comfort of your home before deciding to buy, which is 100% risk-free!

Besides, you also get 5 years extended warranty when registered online, the longest warranty period in the industry.

Check Price on NU Aqua Now

The Pros & Cons of NU Aqua Efficiency Series Tankless RO System

Pros
  • Strong water filtration removes 99% of contaminants.
  • Long lifespan of RO filter
  • Great water efficiency of 2:1 clean water to wastewater ratio
  • Fast water output rate of 600 GPD
  • Short and compact design
  • 120-days trial period
  • 5 years extended warranty
  • Smart faucet with a filter life indicator
Cons
  • No built-in TDS display to monitor the water quality
  • Slightly expensive
  • No NSF certification

Should You Buy the NU Aqua Efficiency Series RO System?

If you are the type of person that prefers to try out a product before buying, then this is for you. It offers a 120-day home trial period and a 5-year warranty period after you bought.


5. iSpring RO500-BN Tankless RO System [Review] – Alternative Choice

5. iSpring RO500-BN Tankless RO System [Review] - Alternative Choice Image
Highlights:
  • Water Filtration: 5 stages
  • Water Output Rate: 500 GPD
  • Water Efficiency Ratio: 2:1
  • Features: Filter life display, real-time TDS monitoring

The iSpring RO500 is another choice of tankless RO systems with a slim body design, fast 500 GPD output rate, 2:1 pure water to wastewater ratio, and removing 99% of contaminants in water.

It features a filter life indicator, real-time water quality monitoring, and quick filter replacement.

It is designed and assembled in the US and backed by a 1-year warranty with a 30-day money-back guarantee.

Check Price on Amazon Now

The Pros & Cons of iSpring RO500 Tankless RO System

Pros
  • Slim body design.
  • Fast 500 GPD production rate.
  • Great water efficiency with 2:1 pure water to wastewater ratio.
  • Useful features like filter life indicator, real-time water quality monitoring, and smart leakage protector.
  • Easy to install and quick to replace filters.
Cons
  • Slightly expensive

Should You Buy the iSpring RO500-BN System?

If you are a fan of the iSpring brand and like the slim profile of this tankless RO system, then is a great choice.


Comparison Table of the Best Tankless Reverse Osmosis Systems

Here are the comparison of the 5 best tankless RO systems in the market:

Model

Waterdrop G3P800

Waterdrop D6

Frizzlife PD600

NU Aqua 600GPD

iSpring RO500-BN

Filtration Stages

7

5

7

4

5

Output Rate

800 GPD

600 GPD

600 GPD

600 GPD

500 GPD

Water Efficiency

3 : 1

2 : 1

1.5 : 1

2 : 1

2 : 1

TDS Display

Yes

Yes

Yes

No

Yes

Filter Life Display

Yes

Yes

Yes

Yes

Yes

Smart Faucet

Yes

Yes

No

Yes

No

Leak Detector

Yes

No

No

No

No

Alkaline Water

Add-on

Add-on

Yes

No

No

UV Filter

Yes

No

No

No

No

Certification

NSF 58, 372

NSF 58, 372

No

No

No

Dimension

18.11” x  5.67” x 17.72”

15.98” x  5.98” x 11.97”

15.5" x  5.3" x 14.7"

9.25” x 9.75” x  18.25”

16.25” x  5.125” x 17.5”

Price

$$$$$$

$$$

$$$

$$$$

$$$$

Product link


Advantages of Tankless Reverse Osmosis Systems vs Normal RO Systems (tank-based)

A tankless Reverse Osmosis system does offer many advantages over traditional tank-based RO system such as:

  • Higher water efficiency: Tankless RO systems usually provide a 1.5:1 to 3:1 clean water to wastewater ratio, whereas normal RO systems usually provide 1:3 to 1:2.
  • Faster water production rate: Tankless RO systems produce clean water at a rate of 300 to 800 GPD, whereas the production rate of normal RO systems production rate is 50 to 100 GPD.
  • Better design: Most tankless RO systems have a better design that fits into a modern kitchen.
  • More space-efficient: Without a water tank, the body size is slim and more compact.
  • Easier to install and maintain: Tankless RO systems have fewer components like tubing and connection points, no water tank, and the filters can be twisted in and out easily.
  • Less likely to have water leaking issue: Tankless RO systems have fewer connection points and some of them have built-in leakage detectors.

Also, many modern tankless RO systems come with smart features like real-time TDS monitoring and filter life indicator.

Besides, most tankless RO systems have a twist-in and twist-out filter replacement mechanism, which make changing filter a quick and easy job.

Due to the no-tank design, tankless RO systems won’t have the secondary contamination issue, and some people dislike the water taste from normal RO systems due to the water tank.

Disadvantages of Tankless Reverse Osmosis Systems vs Normal RO Systems (tank-based)

If you suddenly need a large amount of drinking water, like 2 to 3 gallons, a tankless RO system will take more time to fulfill your need than a normal RO system.

While tankless RO systems are quite fast with around 0.4 to 0.5 GPM, a normal RO system can provide clean drinking water at a faster rate (1 to 1.5 GPM) as the water is pre-filtered and stored inside the tank.

But of course, you can buy a separate water tank and pre-fill the water from the tankless RO system to overcome this.

Next, tankless RO systems require electricity to operate, whereas most normal RO systems do not require electricity.

Lastly, due to more features, a tankless RO system usually costs more than a normal RO system.

What to Consider When Buying the Best Tankless Reverse Osmosis System (Guide)

Water Efficiency: Clean Water to Wastewater Ratio

When comes to water efficiency, the best one is Waterdrop G3P800 with a 3:1 clean water to wastewater ratio, but it is also the most expensive unit, whereas the Frizzlife PD60 has the lowest water efficiency among the best tankless RO systems at 1.5:1 ratio, but it is the cheapest option.

The other three have a 2:1 clean water to wastewater ratio.

The better the water efficiency, the more water you are going to save in long run, so make sure you take this factor into account when deciding the right tankless RO system for your home.

Water Output Rate

As tankless RO systems produce clean water on-demand, therefore the water output rate is an important factor in reducing the wait time of filling up a cup or bottle.

The best tankless RO system with the highest water output rate is the Waterdrop G3P800 RO system, which produces clean water at 800 GPD, taking less than 7 seconds to fill up a standard cup.

The iSpring RO500-BN has the lowest output rate in the list, which is 500 GPD or about 11 seconds to fill up a standard cup, which is still acceptable for RO water.

The other three have a 600 GPD water output rate.

Alkaline Water Needs

As a Reverse Osmosis membrane will remove most of the contaminants including beneficial minerals to make the water as pure as possible, however, some people do not enjoy the taste of pure water as it tastes flat.

So, if you prefer the taste of alkaline water, you may choose a tankless RO filter that has a remineralization filter to improve the alkalinity and taste of water.

From the list, the Frizzlife PD600 RO System has a remineralization filter, the Waterdrop G3P800 and D6 have a remineralization filter as an optional add-on, and the rest tankless systems require you to buy a separate remineralization filter.

RO Filter Lifespan

The lifespan of the RO filter will affect the annual operating cost as it is the most expensive filter in a tankless RO system.

The NU Aqua Efficiency Series and iSpring RO500-BN have the longest life RO membranes which last from 24 to 36 months, followed by the Waterdrop G3P800 and Frizzlife PD600 which can last up to 24 months, and Waterdrop D6 that last up to 12 months.

Available Space

Space is another factor to consider especially for homes with a small kitchen.

Fortunately, the tankless RO systems usually come in a compact size, but you may need to consider their shape and dimension to make sure they can fit under your kitchen sink.

Here are the dimensions of the listed tankless RO systems:

  • Waterdrop D6 – 15.98” (H) x 5.98” (W) x 11.97” (L) – Shortest length
  • iSpring RO500-BN – 16.25” (H) x 5.125” (W) x 17.5” (L) – Slimmest
  • NU Aqua Efficiency Series – 9.25” (H) x 9.75” (W) x 18.25” (L) – Shortest height
  • Frizzlife PD600 – 15.5″ (H) x 5.3″ (W) x 14.7″ (L)
  • Waterdrop G3P800 RO System – 18.11” (H) x 5.67” (W) x 17.72” (L)

UV Filter

If your water quality is very bad and could potentially contain microorganisms like viruses, then having a UV filter will add an extra layer of protection to your family.

Out of the 5 best tankless RO systems above, only the Waterdrop G3P800 has a UV filter, and the others will require you to buy a separate UV filter.

Guarantee & Warranty

Product guarantees such as return, trial, and warranty periods will reduce the risk of purchasing the wrong product and boost the confidence level of consumers.

The NU Aqua Efficiency Series RO system offers a generous 120-day home trial period and 5 years warranty when registered online, the best among the listed tankless RO systems.

The other four tankless RO systems have a 30-day return period, enough for you to try out the products.

Other Features

Useful features can make our life easier, here are the features of the 5 best tankless RO systems:

  • Waterdrop G3P800 – Filter life display, real-time TDS monitoring, smart faucet, and water leak detector.
  • Waterdrop D6 – Filter life display, real-time TDS monitoring, and smart faucet.
  • Frizzlife PD600 – Filter life display and real-time TDS monitoring.
  • NU Aqua Efficiency Series – Filter life display and smart faucet.
  • iSpring RO500-BN – Filter life display and real-time TDS monitoring.

Conclusion: The Best Tankless Reverse Osmosis System Is the One That Fit Your Requirements and Budget

By now you should fully understand the benefits of a tankless Reverse Osmosis system.

The list of best tankless Reverse Osmosis systems featured in this article are among the best in the industry, so choose the one that fit your needs and budget the most, and start enjoying clean RO water!

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