Best 6-Stage Reverse Osmosis System

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Getting the best reverse osmosis system grants you instant access to clean, healthy, and great-tasting water.

Unfortunately, you can be overwhelmed by the high number of choices you get when looking for one.

Luckily, we are here to help. In this guide, we review the best 6-stage reverse osmosis systems you can find today. Keep reading

Quick Comparison Chart

BrandiSpring RCC7AKWaterdrop WD-D6-BAPEC ROES-PH75Express Water ROUV10DCGGeekpure RO6-UV
Dimensions (inches)14.5 x 5.25 x 18.515.99 x 6.1 x 11.9716 x 5.25 x 17.514 x 5 x 1514.2 x 9.5 x 18.1
Weight (pounds)26.4622.627.028.022.05
Water flow rate  75 GPD  600 GPD  75 GPD  100 GPD  75 GPD
Pure-to-waste water ratio  1:3  2:1  1:3  1:3  1:2
Remineralization filter  Available  Not available  Available  Not available  Not Available
UV filterNot availableNot availableNot availableAvailableAvailable
Faucet typeLead-free brushed nickel faucetSmart faucetLead-free designer faucetDeluxe chrome faucetLead-free deluxe kitchen faucet
Feed pressure45-70 psi14.5-87 psi40-85 psi40-80 psi40-100 psi
DesignWith tankTanklessWith tankWith tankWith tank
CertificationNSF/ANSI 58 certified  NSF Certified  WQA certified  NSF certified  NSF certified
Warranty period1 year limited manufacturer warranty1-year manufacturer warranty and seller combination2 years extended warranty on registration     1 year manufacturer warranty

1. iSpring RCC7AK Reverse Osmosis System

The RCC7AK is a reliable and ultra-safe RO system from iSpring that converts tap water into pure and healthy drinking water.

The system is exclusively designed to remove up to 99% of 1,000+ contaminants from water and restore its natural alkalinity and mineral balance.

It can produce up to 75 gallons of water daily and has a filtered-to-waste water ratio of 1:3

Some of the key features that make the RCC7AK one of the best 6-stage RO systems include:

Superb filtration performance

The unit is a multi-layered filter system that protects against thousands of harmful water contaminants, including arsenic, asbestos, fluoride, lead, chlorine, calcium, sodium, and more.

Alkaline remineralization

With an alkaline remineralization filter, this system restores essential minerals lost during the filtration process. It helps attain balanced alkalinity giving your water a better taste.

Transparent 1st stage housing

The transparent housing is an easy way to inspect the sediment filter.

It enables you to view the contaminants being removed from the water and gives an idea of when to replace the filters before a problem occurs.


The system comes with push-connect fittings and color-coordinated tubing that ease installation and prevent leaks.

Additionally, the O-rings are made of high-quality materials to ensure that the filters are properly sealed to prevent leaking.

NSF certification

All iSpring’s products undergo rigorous testing for cycle resistance, air leaks, and pressure to maintain high performance, and the RCC7AK is no exception.

It is certified against NSF/ANSI 58 for TDS reduction


  • Produces 75 gallons of pure water daily
  • Remineralization balances pH and improves taste
  • Has premium-quality filters
  • Fairly easy to install
  • High-quality components
  • Backed by a 1-year limited manufacturer warranty


  • Wastes a lot of water
  • No UV light to kill microorganisms

2. Waterdrop WD-D6-B Reverse Osmosis System

The Waterdrop D6 is a high-quality RO system from Waterdrop that uses 6-stage composite filters to remove water contaminants.

The filter reduces pollutants from water, including lead, TDS, chlorine, salt, nitrates, sodium, chromium, and PFAS, among others.

This unit has a capacity of 600 gallons, a pure-to-drain ratio of 2:1, and can produce up to 600 GPD.

Some of the reasons why you would love the D6 include;

Tankless design

The water filter system features a tankless design that saves up to 70% of under sink space. The design prevents recontamination, which usually occurs in tanked/traditional systems.

Smart designer faucet

With a smart designer faucet, the D6 lets you know the TDS level in your water with a simple glance.

The high-end screen on the faucet shows the remaining filter life as well.

Innovative internal pump

The system has an innovative internal pump that lets you fill a glass of water in 8 seconds. It is also the reason for the low drain ratio of 2:1.

Easy installation

With simple DIY skills, you can install the unit in less than 45 minutes. Note that you need an electrical outlet to operate the system.

Filter replacement is also easy thanks to the push-in replacement design that allows you to replace filters in 2 seconds without using tools.

Zero leaks

The D6 has passed numerous tests indicating that it avoids leaks. Compared to ordinary reverse osmosis systems, it has a better sealing effect and fewer connectors in the water circuit.


  • Compact shape
  • Tankless design prevents secondary pollution
  • Sleek, sophisticated appearance fits modern settings
  • Easy installation and filter replacement
  • Has a TDS  monitor and filter life tracker
  • Supported by a 1 year manufacturer warranty


  • No remineralization
  • Loud operation

3. APEC ROES-PH75 Reverse Osmosis System

The APEC-ROES-PH75 is a premium-made RO system from APEC guaranteed to remove up to 99% of water contaminants.

The unit reduces water pollutants such as toxic fluoride, lead, arsenic, chlorine, odor, VOCs, and nitrates, among others.

It can produce up to 75 gallons of pure water daily and has a drain ratio of 1:3.

Some of the key features that make the APEC ROES-PH75 worth investing in include:

Long lasting filters

The system comes with super-efficient double-carbon APEC blocks uniquely designed to achieve maximum chlorine and chemical removal from water.

The large carbon block surface maximizes contact time to enhance water purity. It also multiplies the lifetime of filters and membranes.

Premium alkaline filter

The APEC ROES PH-75 boasts a premium calcium mineral cartridge that adds only high-purity calcium carbonate to raise the pH of the water effectively.

It provides only essential alkaline water without additives for your health.

Superb taste

The model produces great-tasting water that is more distinctive than water from RO units from other brands.

Easy installation and maintenance

Setting this system up is easy and takes about 30 minutes to complete the project. Just follow the step-by-step installation instructions to get it up and running.


  • Supreme quality
  • Hooks up to the fridge with ease
  • Clear installation instructions
  • Has a remineralizing filter
  • Reasonably priced


  • Expensive replacement filters

4. Express Water ROUV10DCG Reverse Osmosis System

You can never go wrong with an RO system from Express Water. The brand makes top-notch water filtration systems to help you experience what pure water should taste like.

Their filters are engineered to work together to produce the purest and most great-tasting water the world has to offer.

The ROUV10DCG is one of Express Water’s high-quality RO systems that offers pure water comparable to bottled water. It provides efficient filtration and quick delivery of healthy drinking water.

So, what makes this system worth your money?

Fast flow rate

The ROUV10DCG produces up to 100 GPD and 0.8 gallons of pure water per minute. It makes enough water for any medium-sized family and has a filtered-to-waste water ratio of 1:3.

Space-saving design

The unit comes in a compact design to fit under the counter in a cabinet. It is therefore best for small apartments, residential homes, RVs and office uses.

It can be wall mounted or freestanding, as it is made for indoor use. You can install it under the sink, in the basement, or in any remote location.

Ultraviolet filtration

The system’s UV filter reduces up to 99.9% of cysts, coliform, and other living impurities from well or natural water sources.

It removes the impurities without adding chemicals to your water.

Easy filter swap

Filter changes are easy and quick thanks to the labeled color-matched connect system.

Additionally, the pre and post-filters require changing only twice a year. The RO system is replaced only once every year.

Each filter is double-sealed to provide filtration efficiency and value.


  • Produces 100 GPD
  • Powerful UV filtration
  • Easy to install
  • NSF/ANSI standards 42,50,401 certified
  • Perfect for well water


  • No remineralization

5. Geekpure RO6-UV Reverse Osmosis System

Last on the list is the RO6-UV system from Geekpure, a leading water filtration, and purification manufacturer for over 2 decades.

The company makes high-quality RO systems, and the RO6-UV is no exception.

Like all other systems in this list, the RO6-UV filters water in 6 stages. It eliminates 1,000+ water contaminants, including heavy metals, chlorine, fluoride, and cadmium, among others.

Some of the key features of the RO6-UV include the following:

Premium quality components

The system boasts high-quality components that ensure reliability and low maintenance for years to come.

All tubes, quick-connect fittings, and storage tanks are well-made to offer you the best value for your money. The reverse osmosis membrane is NSF certified to provide pure and healthy water.

UV filter

The unit comes with a UV filter that destroys all microorganisms in the water, making it healthy and ultra-pure for drinking and cooking.

Low drain ratio

The RO6-UV produces 75 gallons of water daily and a pure water-to-drain ratio of 1:2.For every gallon of water produced, 2 gallons go down the drain.

Quality quick connect fittings

Get this unit, and you won’t waste your money on professional installation. It has color-coded tubing, premium quality quick-connect fittings, and videos for easy DIY installation.


  • Comes with a UV filter
  • Easy to install and maintain
  • Produces great-tasting water
  • Backed by a 1 year manufacturer warranty


  • Poor installation instructions
  • No remineralization


It is believed that the higher the number of filtration stages, the better the quality of the water produced.

Therefore, Investing in a 6-stage reverse osmosis system gives you a better chance of getting pure and great-tasting water for your home.

Our list contains the best 6-stage reverse osmosis systems you can get on the market today. It is all-inclusive, with some units offering remineralization and others UV filtration.

Whether your water comes from a private well or municipal water, you will get a model that suits your needs. All you need to do is go through each unit’s key features and pros and cons. Happy hunting!

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Dr. Peter Gleick

Dr. Peter Gleick is an experienced water filtration engineer and technical writer for He is an expert in water purification and filtration, focusing on helping people get clean, safe, and healthy water for domestic use. He has more than 10 years of writing experience and has numerously contributed to leading publications in this field.

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