Smallest Reverse Osmosis System | (Updated June 2023)

Do you live in a small house? Or is there too little space in your kitchen? Are you looking for the perfect RO system for your small kitchen? If so, this article is for you. We’ve listed some high quality reverse osmosis systems for you small space. The WECO TINY-36 is the smallest reverse osmosis system on our product list. For your convenience, we also added the best countertop and two tankless reverse osmosis systems. All the products have been selected based on excellent features and customer reviews. Keep reading this article and pick the perfect RO system for you.

Smallest Reverse Osmosis System Reviews

1. FS-TFC (FS-RO-100G-A) Small Reverse Osmosis System

Product Information

  • Dimensions: 11.5 X 5 X 11.5 inches
  • Filer stage: 5 stages
  • Capacity: 115 Gallons per Day
  • Weight: 13.3 pounds
  • Installation Method: Wall-mounted or floor-standing
mini roy fs-tec

FS-RO-100G-A is the first RO system on our list. The compact design of this RO system makes it unique. FS-RO-100G-A is a wall-mounted reverse osmosis system but, you can install it under the sink easily. It’s a most effective reverse osmosis system and can remove different contaminants that may contain in water.

FS-TFC is one of the best small reverse osmosis systems. This RO system can filter 18 liters water in an hour. That means you will get one glass (200ml) of filtered water every 5 seconds.

The FS-RO-100G-A is very effective at removing the most common water contaminants. It can remove up to almost 100 percent of health hazard elements from water. Heavy metals, lead, and arsenic is dangerous for our health. This mini reverse osmosis system removes these health hazard metals effectively.

The aforementioned RO system is made of lead-free supreme quality metal. FS-TFC reverse osmosis water filtration system also comes with a brushed nickel faucet and quick connecting fittings. The 3.2 gallons storage tank of this RO system supply sufficient water for immediate use.

Though, FS-TFC is a long-lasting reverse osmosis system but provides lifetime technical support. It also comes with a 1-year warranty. So, you can try this extraordinary RO system to enjoy pure and safe drinking water.


  • Ideal RO system for a small family
  • Removes 1000+ contaminants
  • Compact design and fits in small places
  • Easy to install
  • 1-year warranty


  • Not perfect for big family and offices

2. WECO TINY-36 Under-sink Reverse Osmosis Water Filtration System

Product Information

  • Dimensions: 16 X 5.5 X 9 inches
  • Filter Stage: 4 stages
  • Capacity: 36 Gallons per Day (required 65 psi water pressure)
  • Flow Rate: 0.75 Gallons per Minute
  • Temperature Range: 34-110 Degree Fahrenheit
  • Installation Method: Wall-mounted or floor-standing
smallest reverse osmosis system weco tiny

The WECO TINY-36 is another highly efficient smallest reverse osmosis system. It’s tiny in size but not in work. The ultra-small design of this reverse osmosis system allows installation anywhere you want. So, you can set it under the sink, in the bathroom, or even on the boat. For easy use, it comes with a 2-gallons water storage tank. It’s a 4-stage reverse osmosis system that can purify 36 gallons of water in a day.

This small reverse osmosis system features sediment pre-filter that removes sediments, derbies, and other microscopic contaminants. WECO TINY-36 compact under-sink reverse osmosis system also features an activated carbon block. This carbon block eliminates chlorine, chloramines, odors, and many other chemicals that may contain in the city or pre-treated water.

WECO TINY-36 is very efficient in removing heavy metal and common water contaminants. Because, the TFC membrane of this reverse osmosis system removes 99 percent of lead, cadmium, mercury, nitrate, and fluoride.

This reverse osmosis system is quite capable to remove both city and well water contaminants. So, you can buy this excellent reverse osmosis system to enjoy pure, odor-free, great-tasting water.


  • Ultra-small design
  • 2-gallons storage tank
  • Perform well in a high TDS water
  • Removes up to 99 percent contaminants
  • FDA approved material made cartridges
  • Easy installation method


  • Not suitable for big household

3. Home Master TMAFC Undersink Reverse Osmosis Filtration System

Product Information

  • Dimensions: 12 X 16 X 20 inches
  • Filter Stage: 7 stages
  • Capacity: 75 Gallons per Day
  • Weight: 14.5 pounds
  • Temperature Range: 40-100 Degree Fahrenheit
  • Installation Method: Wall-mounted or floor-standing
Home Master TM Undersink smallest reverse osmosis system

Home Master TMAFC is the small reverse osmosis system but features 7-stages of filtration. So, you will get contaminant-free, pure, and healthy water. This reverse osmosis system features a catalytic carbon filtration media that removes up to 98 percent of chlorine, chloramines, and other chemicals.

Slow water flow rate is a big issue for filtration system users. But, Home Master TMAFC RO provides an excellent water flow rate. And, you will never face this issue.

Another good thing about this is that it adds minerals during the filtration process. Its patented Full Contact Technology (FCT) will enhance the taste of your water by adding calcium and minerals. You will get great tasting drinking water after completing the 7-stage filtration process.

The Home Master TMAFC under sink reverse osmosis system features a built-in non-electric permeate pump. It will reduce your water wastage up to 80 percent and increase water production up to 50 percent.

This USA made under sink RO system lasts long. The easily changeable filter also lasts up to 1 year (after using 2000 gallons of filtered water). You only need to change the filter once a year.


  • USA made product
  • Removes 98 percent of dissolved metals, chemicals, and other contaminants
  • Uses patented full contact technology to remineralize filtered water
  • Non-electric permeate pump reduces water wastage up to 80 percent
  • Long-lasting (2000 gallons or 1 year) and easily changeable filter cartridge
  • Comes with 5 years limited warranty


  • Little bit expensive

4. iSpring RCC7AK Reverse Osmosis Water Filtration System

Product Information

  • Dimensions: 15 X 8 X 18 inches
  • Weight: 20 pounds
  • Filter Stage: 6 stages
  • Capacity: 75 Gallons per Day
  • Temperature Range: 40-100 Degree Fahrenheit
ispring water softener price comparison

iSpring is a famous brand for producing quality water treatment systems. The RCC7AK is the small size reverse osmosis system and uses a 6-stage filtration method to purify water. Because of its small size, this under-sink filtration system is easily adjustable in any spaces. The iSpring RCC7AK reverse osmosis system also comes with a European standard faucet to ensure purified water without any hassle. so, don’t worry about its quality.

At the first stage, a 5-micron sediment filter removes the dirt, rust, and slit.

Then chlorine taste, odors, mineral oils, and hydrocarbons are eliminated in the second stage by using a Granular Active Carbon (GAC) filter.

After that, the filtered water passes through the carbon block filter. This carbon block eliminates residual colors and different chemicals like chloramines.

 At the fourth stage, a semi-permeable RO membrane is used to filter out heavy metals like lead, arsenic, chromium, TDS(Total Dissolved Solid), and most other water contaminants. The fourth stage also removes micro-organism and parasitic cysts. 

Then the filtered water passes through the finer GAC filter. At the final stage (6th), the alkaline and mineral filter adds a small amount of calcium and magnesium minerals. so, your water will be slightly alkalized and very tasty.

iSpring RCC7AK Reverse Osmosis System comes with 30 days money-back guarantee and 1-year limited warranty.


  • Certified to remove 99.99 percent of over 1000 water contaminants
  • The alkaline stage makes water tasty
  • The re-mineralization stage adds health beneficial minerals
  • Comes with easy installation instructions and videos 
  • 1-year money-back guaranty
  • Lifetime technical support by the manufacturer


  • Some user claimed lower system efficiency 

Tankless Undersink Reverse Osmosis System

1. Frizzlife PD600 Undersink Reverse Osmosis System

Product Information

  • Dimensions: 18 X 17.6 X 15.6 inches
  • Capacity: 600 Gallons per Day 
  • Flow Rate: 0.48 Gallons per Minute               
  • Filtration Stage: 6 stages
Frizzlife RO Reverse Osmosis Water Filtration System

The Frizzlife PD600 is another efficient reverse osmosis system on our list. This reverse osmosis system comes with a space-saving tankless design. So, the compact filtration system with small footprint design will save your storage space under the sink. On the other hand, no tank design also secures the water from secondary pollution. 

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This Frizzlife PD600 also re-mineralizes and alkalizes the filtered water. RO membrane filtration is the most common stage of any reverse osmosis system. You may know, this RO membrane removes natural minerals from water. But, don’t worry; the Frizzlife PD600 will restore the minerals in the 3rd stage of the filtration process. This RO system also alkalizes the water and adjusts the PH level in this stage.

Another positive side of reverse osmosis system is the high and stable flow rate. So, the Frizzlife PD600 can serve 600 gallons of water per day. And it’s enough for a big family or small offices.

The Frizzlife PD600 features a smart LED display. This LED will inform you of the real-time out TDS and filter status. Frizzlife PD600 comes with all kits to make your installation easy. You can install your RO system in a few minutes by watching the provided videos and instructions


  • Smart LED feature
  • Space-saving tankless design
  • Almost 100 percent contaminants removal capacity
  • Eco-friendly and cost-effective 
  • Easy installation and filter replacement system
  • Longer lifespan


  • No negative side

2. Waterdrop WD-G3-W Undersink Reverse Osmosis System

Product Information

  • Dimensions: 18.06 X 5.68 X 17.76 inches
  • Filer stage: 7stages
  • Capacity: 400 Gallons per Day
  • Water flow rate:0.28 Gallons per Minute
  • Weight:31 pounds

The Waterdrop Wd-G3-W is one of the best under sink RO systems that comes with some excellent features. It’s a seven stages water filtration system and supplies a sufficient amount of pure and clean water for your family. 

The Waterdrop Wd-G3-W has some special features that make it the best on the market-

  • Tankless Compact Design

The tankless compact design saves storage space in the kitchen. The Waterdrop Wd-G3-W filter water on demand and doesn’t use any storage tank. This on-demand filtration system will help you to avoid secondary pollution of your water.

  • Composite filter Element

The Waterdrop Wd-G3-W is the first reverse osmosis system that uses the composite filter in the US market. The pre-sediment, carbon block, and RO membrane filter complete a 7-stages filtration system. And, this activated carbon block filter is made from natural coconut shell. This coconut shell carbon improves the test of water.

  • Easy to Install Design

The Waterdrop reverse osmosis is designed for easy installation. So, you can complete your installation process in a few minutes. You can also change the filter just only in a few seconds.

This reverse osmosis system is NSF 58 certified for TDS reduction. The Waterdrop Wd-G3-W also NSF-372 certified for using lead-free materials.


  • Long-lasting system and filter cartridge
  • Lead-free material made RO system
  • Features filter change indicator
  • Ideal for both small and large house
  • Capable to reduce fluoride
  • NSF certified


  • Price is relatively high

Best Countertop Reverse Osmosis System

1. Alcapure Countertop Reverse Osmosis Water Filter

Product Information

  • Dimensions: 14.5 X 9.5 X 16.25 inches
  • Filter Stage: 4 stages
  • Filter Capacity:  1000 Gallons per filter or 1 year
  • Weight: 14.5 pounds
AlcaPure countertop reverse osmosis water filter reviews

The Alcapure is one of the best four-stage countertop reverse osmosis systems. This RO system can remove up to 99 percent of contaminants like lead, chromium, mercury, arsenic, and other heavy metals. 

This reverse osmosis system also has a remineralization stage. The reverse osmosis systems remove minerals from water in the filtration process. In the remineralization stage, a small amount of calcium and magnesium mineral is added in this stage.

This remineralization process also adjusts the PH level and makes water healthy and tasty.


  • Installation free (zero Installation) system
  • Attractive design
  • BPA-free water tank
  • Portable and space-saving design
  • Re-mineralization stage available.


  • Only 30 days return policy which is not enough

Smallest Reverse Osmosis System Buying Guide

In this section, we have added a short buying guide to make your decision easy. Keep reading our reverse osmosis system buying guide and select the best reverse osmosis system for you.

What is a Reverse Osmosis System?

Reverse osmosis is the water purification system. And it eliminates contaminants from water. A semi-permeable membrane is used in this process. This membrane filter out ions, unwanted molecules, and larger particles. 

What is reverse osmosis

The semi-permeable membrane allows only water to pass through it. But, blocks contaminants from the entering side. Some reverse osmosis systems also add some extra features to purify water completely.

What Should Consider Before Buying a Reverse Osmosis System?

Before buying a reverse osmosis system, you should consider some key factors. Let’s take a look-

• Water Demand

It should be the number one priority when buying a reverse osmosis system for your home. Calculate your daily water usage and select the appropriate one according to your needs. The capacity of any reverse osmosis system is measured in GPD (Gallons per Day). Be sure to check the capacity of any row system before buying it.

• Budget

The budget is another important matter that most of the buyers consider before buying. Check the price, maintenance, and installation cost of the RO system you want to buy.

• Water Pressure

Water pressure is important for efficient working of a RO system. The reverse osmosis system doesn’t work properly under the 40 psi pressure of water. For this, you can use a booster pump to increase the pressure of your water.

• Source of Water

All reverse osmosis systems will not be perfect for both city and well water. Because, contaminants of the city and well water are not the same. Some row systems work well for city water, while others perfect for well water. 

• Re-mineralization

Reverse osmosis systems remove health beneficial minerals from water. So, some RO systems feature a re-mineralization stage. You can consider buying a RO unit that has an alkaline re-mineralization filter.

How to Install a Smallest Reverse Osmosis System?


We have covered some smallest reverse osmosis system reviews and we hope this article has helped you to find the best unit for you. You can pick your appropriate one from our reviewed product list. You can also contact us for more information.