Cheapest Reverse Osmosis Systems (2024 Bargain Guide)

Last Updated Feb 16, 2024
Disclosure: As an Amazon Associate I earn from qualifying purchases.

RO systems don’t have to be expensive. In fact, almost everyone can afford a system that delivers bottled-water quality water on tap right at home. Did you know that a lot of bottled water companies sell reverse osmosis water? The trick is the companies add minerals “for taste” to give the final product its signature flavor. In this article, I teach you how to choose the cheapest reverse osmosis system that’s actually worth buying.

Along with the tips, I share the 5 best budget reverse osmosis systems currently available, reviews of each system, and the pros & cons of owning them. By the time you leave here today, you’ll be well on your way to owning an RO system. RO systems are excellent for both municipal and well water because they remove everything. Whether you’re dealing with hard well water or municipal water treated with pesky chloramines, an RO system is the backbone of any good home drinking water filtration system.

#1) Aquatic Life RO Buddie Reverse Osmosis System

  • #1 Cheapest Reverse Osmosis System
  • Stages: 3
  • Capacity: 50 GPD
  • Model: 540016
  • Dimensions: 7.2″ x 4″ x 13.8″ (L x W x H)
  • Weight: 3.1 lbs
  • Warranty: 1-Year
  • Price: $
#2) Whirlpool RO Water Filtration System

  • #1 Best Budget Reverse Osmosis System
  • Stages: 3
  • Capacity: 18.4 GPD
  • Model: WHAROS5
  • Dimensions: 11.5″ x 3.5″ x 9″ (L x W x H)
  • Weight: 6.14 lbs
  • Warranty: 1-Year (extendable to Lifetime)
  • Price: $$
#3) FS-TFC Under-Sink RO Water Filtration System

  • Cheapest 5-Stage RO System
  • Stages: 5
  • Capacity: 100 GPD
  • Model: FS-RO-100G-A
  • Dimensions: 11.5″ x 5″ x 11.5″ (L x W x H)
  • Weight: 14 lbs
  • Warranty: 1-Year
  • Price: $$
#4) Express Water Reverse Osmosis Water Filtration System

  • Best Value for the Money
  • Stages: 5
  • Capacity: 50 GPD
  • Model: RO5DX
  • Dimensions: 16.2″ x 18.8″ x 18.1″ (L x W x H)
  • Weight: 11.8 lbs
  • Warranty: 1-Year
  • Price: $$$
#5) HiKiNS Reverse Osmosis Water Filtration System

  • Best for Large Families
  • Stages: 5
  • Capacity: 125 GPD
  • Model: RO-125G
  • Dimensions: 14.6″ x 5.1″ x 15.2″ (L x W x H)
  • Weight: 23.1 lbs
  • Warranty: 2-Year
  • Price: $$$

Cheapest Reverse Osmosis System Reviews

When shopping for the best budget reverse osmosis system, you have the option to go with a bare-bones tankless system up to a 5-stage under-sink system. Depending on your budget and planned use(s) for the system, you’ll find that the 5-stage systems in this guide deliver the most delicious-tasting water of the bunch. While the Aquatic Life system does make RO drinking water, most people buy it for aquarium use or for gardening. Having said that, the price is unbeatable for a home system that does make purified drinking water.

Once you graduate from a bare-bones system, you’ll notice that most systems include tanks and auxiliary faucets. A tank is important to have to avoid having to wait around for the system to pour you a glass of water. Instead, the system fills the tank to provide you with on-demand RO drinking water. Clearly, a system with a tank is more convenient for couples and families who drink more water than a single person. Before I jump into the reviews below, I want to answer one question.

What’s the difference between a 3-stage and 5-stage RO system?

A 5-stage system typically includes 2 additional carbon filters. One additional pre-filter before the water enters the RO membrane and an additional post-filter that comes after the RO membrane. This final-stage carbon filter is often referred to as a “polishing” filter because it makes the water taste better by removing any residual taste and odor.

The additional carbon pre-filter helps to extend the life of the RO membrane and overall system efficiency for a better end product than a single carbon pre-filter. Both 3-stage and 5-stage systems include a sediment pre-filter, which needs to be replaced most often of the filters in the systems.

Now that you’ve considered your options, let’s jump into the reviews.

Aquatic Life RO Buddie Reverse Osmosis System (540016)

Of the systems in this guide, the RO Buddie 540016 is by far the cheapest reverse osmosis system. It’s actually kind of amazing that the company is able to sell a system for this cheap. However, it’s important to keep in mind that this system is as bare-bones as it gets. There’s no included faucet, tank, and the filtered water flows from a small hose unless you decide to purchase a separate faucet and tank. Once you factor in the cost of those additional accessories, the price is very similar to the Whirlpool unit below.

Despite those missing accessories in the base package, this is still one heck of a deal. If you plan to use the system for an aquarium, you’d be hard-pressed to find a better bargain for a quality system. The clear advantage of this system is its size. It takes up barely any space and can be used virtually anywhere inside your home, RV, or apartment. There’s no need to drill any holes or crawl under the sink for a complicated installation procedure. The package includes the required faucet adapter to get up and running quickly out of the box.

The system itself is quite easy to maintain. There are two pre-filters: 1 sediment and 1 activated carbon. Fewer filters equal fewer filters to keep track of and less cost to replace them when it’s time. Lastly, the fact that this compact system has the ability to pump out 50 gallons of RO water per day is impressive in itself. All in all, I’m a fan of the RO Buddie, and it’s an absolute steal for the price.

  • Very clear instructions that help the user get the most out of the system
  • A leak-free system with reliable push-pull connectors
  • The 50 GPD rating is accurate, if not low
  • 5 ppm filtered RO water reports and consistently low ppm readings
  • Super simple to install compared to a traditional under-sink RO system
  • Inexpensive replacement filters that are easy to replace
  • The compact size is great for small spaces
  • Great-tasting RO water
  • Very slow flow rate reports
  • Produces more wastewater than more efficient systems
  • Shorter filter life than other systems
  • A handful of quality control issues reported

Whirlpool RO Water Filtration System (WHAROS5)

Of the 5 systems in this guide, the WHAROS5 is definitely the best budget RO system. Like the RO Buddie, it surprises me how cheap this system is, especially considering that Whirlpool is a name we all know. If you want a complete system and to steer clear of a lesser-known brand, this is the system for you. Unlike the RO Buddie, it comes with everything you need for a complete under-sink system installation. The 3-gallon tank is more than enough for 1-2 people, and the attractive chrome faucet matches just about any kitchen.

What I like most about this system is how easy it is to use. If this is your first RO system, this system is a great entry-level system that stands the test of time. I read over the warranty info, and the steps to qualify for the free lifetime warranty are easy to follow. There’s no need to jump through any hoops to get the free extension above the included 1-year warranty. You’ll also enjoy the EZ-change indicator light that tells you when to change the filters. With other more complicated RO systems, it’s necessary to keep track of the filters yourself and monitor them. This compact Whirlpool unit makes life easier.

On top of that, an easy filter change feature allows you to change the filters in seconds with no need to turn off the water supply. This is the ultimate convenience. Finally, the compact size of the WHAROS5 makes it great for small spaces with its 3.5″ width and smaller 3-gallon filtered water tank.

  • Good pressure at the filtered water faucet when the tank is full
  • Very easy to install with clear instructions included
  • Replacing the filters is incredibly easy compared to other systems
  • Easy to adapt with a T fitting for crystal-clear ice cubes
  • Bottled-water quality taste
  • More compact and cheaper than the previous model
  • Easy to fit into tight spaces or under sinks with limited space
  • You may want to upgrade the faucet to something better
  • 1:3 wastewater ratio (3 gallons of wastewater for every 1 gallon of RO water)
  • Low max daily output capacity

FS-TFC Under-Sink RO System (FS-RO-100G-A)

Now we’re moving up the ladder to 5-stage systems. Amazingly enough, this system doesn’t cost much more than the Whirpool unit. At the time of this writing, the FS-RO-100G-A is the cheapest 5-stage reverse osmosis system that’s worth the money. What’s really nice about this system is its compact size. Compared to most standard 5-stage systems, it’s a few inches shorter and narrower, making it great for small spaces and smaller households.

One clear advantage of this system over the Whirpool system is the included faucet. This system features a brushed nickel faucet made of 304 stainless steel. If you factor in the potential extra cost of a different faucet for the Whirlpool system, the FS FS-RO-100G-A is actually cheaper. The disadvantages of this unit compared to the Whirlpool are more filters to maintain, no easy-change filter feature, and the installation is a bit more complicated.

One thing I found interesting about this system is that it includes 2 sediment filters in the pre-filtration stages rather than the typical 2 carbon pre-filters. That’s certainly something to keep in mind before you buy it, though, you might find that 2 sediment filters are better than 2 carbon filters depending on your water supply. A final consideration is the addition of a post-carbon filter for an improved taste that you might prefer over the 3-stage systems above.

  • A responsive seller who stands behind the system and warranty
  • An excellent space-saving RO system
  • You’ll most likely be impressed by the quality of the faucet for the price
  • Expect much faster production with this 100 GPD system than the Whirlpool system above
  • Converts nasty city water into superb-tasting filtered water
  • No leaks
  • The included tank might be to small for larger households
  • Slow flow rate reports
  • A handful of leak reports

Express Water RO Water Filtration System (RO5DX)

Outside of APEC and iSpring, Express Water is the next best thing. To me, Express Water is the best budget reverse osmosis brand. Unlike lesser-known brands, Express Water systems are NSF-certified, made with premium parts, and Express Water’s customer service is top-notch. Unlike the 5-stage FS-RO-100G-A system, the RO5DX is a full-size 5-stage system with bigger, better filters. The incredible part is the RO5DX barely costs more than the FS-RO-100G-A at the time of this writing. It seems like every system in this guide is the best deal, and that’s why they’re all here.

Unlike the FS-RO-100G-A system, this system by Express features 2 full-size carbon pre-filters rather than 2 sediment filters. The single sediment filter in this system is more than enough to tackle municipal water and most well water with a max recommended TDS of 1000 ppm. Be sure to consider the TDS of your tap water before you buy a system to ensure that it falls below the recommended max TDS level. Both the Express and HiKiNS systems have a maximum recommended TDS of 1000 ppm, which makes them the most powerful systems in this guide.

A couple of final points to consider is that this system does require more room below your sink, and there are more filters to maintain than the systems above. However, Express Water includes the first set of replacement filters in this package. To make a long story short, this system gives you the most value for the money of any system on the market.

  • A .8 GPM filtered water flow rate is the best you’ll find in this class
  • Unbeatable value for the money, especially with the 1st set of replacement filters included
  • Awesome customer service
  • The best-rated cheap RO system on the market
  • Express pre-assembles the filters before sending you the unit to save you time on the installation
  • The water tastes even purer than bottled water
  • You may fall into the group of people who don’t like the taste
  • A very small handful of quality control issue reports
  • Several leak reports

HiKiNS Reverse Osmosis Water Filtration System (RO-125G)

The final system is one of my personal favorites by HiKiNS. Like Express Water, I trust the HiKiNS brand. HiKiNS reminds me of a budget alternative to a premium APEC system that sacrifices little if any quality to deliver a budget price. The most important difference between the RO-125G and the other 4 systems in this guide is its 125 GPD max output. The RO-125G is the best cheap reverse osmosis for large families, and it costs roughly the same as the Express system above.

Additionally, this high-output system features a low 1:1 filtered-water-to-wastewater ratio. This is also the best of the systems in this guide and just about the best ratio you’ll find offered by any under-sink system on the market. Are you starting to see why I really like HiKiNS as a top budget brand?

Like the FS-TFC system, the RO-125G features an attractive stainless steel faucet that’s certainly better than the faucet that’s included with the Whirpool unit. One final consideration is the long 2-year warranty that comes standard with the RO-125G. Most systems in this price range offer 1-year.

  • The fastest filtered water production rate of the systems in this guide
  • Clear instructions and easy installation
  • High-quality materials that don’t feel cheap
  • Stands the test of time and consistently delivers very low ppm water
  • An absolute steal for the price
  • The water tastes fabulous
  • Larger than the compact systems in this guide
  • It costs the most at the time of this writing
  • A couple of quality control issue reports that led to leaking

Bottom Line

Now that you’ve checked out the cheapest reverse osmosis systems that are worth the money, you have an understanding of what to look for in the budget department. Be sure to consider how you plan to use the system before you buy it to get the most out of it. When you factor in potential customizations and upgrades, all of the systems in this guide cost roughly the same. It really comes down to your preference.

Lastly, remember that 5-stage systems offer better-tasting water because they typically feature a post-carbon filter to enhance the taste of the final product. If the taste isn’t a huge concern to you, you may prefer the convenience of a 3-stage system over a 5-stage one, particularly the Whirlpool system with its convenience features such as the easy-change filter design.

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