How Much Does an Under Sink Reverse Osmosis System Cost?

Reverse osmosis systems are slowly becoming essential for every household when it comes to water filtration. The increasing demand for the systems has led to the growth of new brands and suppliers as well.

Most people like the under sink RO systems as they are not only compact but also space-saving. These systems don’t interfere with the countertop space at all. You, therefore, get enough space to prep your meals.

The price of under sink RO systems varies widely, with every brand trying to offer a more competitive price than its competitors.

However, you should know that the system’s initial price is just a tiny part of the equation. There are other factors that you’ll need to factor in, including installation and maintenance.

To learn more about the much, you’ll spend on an under sink RO system, continue reading.

Factors Influencing the Cost of Under Sink RO Systems

How Much Does an Under Sink Reverse Osmosis System Cost

1. Brand

Some companies have been in the water filtration industry for decades. As such, they’ve proven to many that they are not only dependable but also reliable.

Since such brands already have a solid customer base, they can sell their products at higher prices than companies with only a few years in the market.

2. System Efficiency

The efficiency of an under sink RO system is determined by 2 things: how fast it can filter water and how much waste water it produces during the process.

All RO systems waste water during the water filtration process. The lower the drain ratio, the more efficient the system is.

Nowadays, you can find under sink RO systems with super low drain ratios of 1.5: and even 1:1 like the Waterdrop G3.

And although such systems might come with a higher price tag, you’ll enjoy the long-term savings.

3. Filtration Stages

Most under sink RO systems filter water in 4 stages. Should you get one with an above-average number of filtration stages, you’ll have to pay more.

For instance, there are some under sink systems that come feature more than double the 4 stages. Don’t be surprised to come across one that filters water in 10 or 12 stages.

Thanks to these extra stages, the water produced is usually very pure. The extra filters might actually be GAC filters, carbon block filter or remineralization filters that restore minerals to your filtered water.

The more filters the system has, the more you’ll spend on replacement filters.

4. Certifications

Certified under sink RO systems cost more since the certifications assure customers that the units are reliable. Everyone shopping for a reverse osmosis system will check whether the unit is NSF/ANSI 58 certified.

The NSF/ANSI certification is the national standard for all RO systems. It indicates that the system in question has been tested and deemed effective.

5. Additional features

Many under sink RO systems come with several extras like a booster pump that boosts pressure to increase water production, flow rate and efficiency and reduces waste water.

Other popular add-ons include remineralization filters that not only restore essential minerals to your water but also help to balance water PH and increase alkalinity.

Average Cost of Tankless Under Sink RO Systems

Average Cost of Tankless Under Sink RO Systems

To get a tankless RO system, you’ll have to part with around $300-$600.You pay more since the system offers the convenience of getting access to clean water from a system that filters water instantly.

You can’t compare such systems with the tank-based ones that take hours to fill the storage water with pure water.

Average Cost of an Under Sink RO System with a Tank

Tank-based under sink RO systems are traditional type POU reverse osmosis filters. Their price ranges between $200 and $600.

You can find a lot of high-quality under sink RO systems at the lower end of this price.

Under Sink RO Systems Installation Cost

Installation costs often include basic labor, supplies and equipment. You also need to factor in modification, relocation and repair of specific components. Inspection and water testing fees are also included.

Under sink RO systems are a little tricky to install, but you can hack it with some basic DIY skills. If you are a handy person, you can get the unit working in less than an hour. You’ll also save yourself some bucks, especially if working with a tight budget.

If you don’t have the DIY skills, don’t worry; just get a professional plumber to install the system for you. It’ll take them minutes to get the job done.

On average, professional installation of an under sink reverse osmosis system range from $150 to $300.You will only pay more if there are modifications to make to your existing plumbing.

In case of major repairs or modifications, the additional charges can push the cost up to $400.

Under Sink RO Maintenance Cost

As aforementioned, the total cost of an under sink RO system includes operation and maintenance costs in addition to the initial price. This is all tied to the frequency of filter replacements.

Filter replacement depends on how heavily you use the RO system and on the quality of the source water. If your water has high chlorine levels, high in sediment or if you usually use large quantities of water, you’ll need to replace the filters more often.

Under sink RO, systems usually boast filters that can last up to 6 months or 1-year.RO membranes take the longest- up to 5 years.

It will cost you around $60 to $ 200 to replace the filters annually (depending on the brand). However, in most cases, the standard range is usually $80 to $100.

If the system you get for your home filters water in more stages, be ready to pay a little more for the expenses. You’ll also pay more if the unit filters come in a modular design, as you’ll have to dispose the entire housing with the filter.

Waste water

The cost of waste water will only apply if you use very high large quantities of water every day. And luckily enough, you’ll notice only a slight difference in your water bill even when using a high-volume application.

Where to Buy Under Sink RO Systems for Your Home

The best place to buy under sink RO systems today is online. Actually, most companies run their stores and purchasing from these stores enables you to enjoy the benefits of factory pricing.

And of course, tops the list of online marketplaces and lists a vast selection of products at competitive prices. Amazon also gives you the advantage of browsing through customer reviews. From these reviews, you can learn the benefits and drawbacks of individual products.

However, if you don’t trust online stores, you can always shop from your local store. The only problem is that you’ll most probably not have much to choose from.

Looking for the best under sink RO system? We recommend the following:

1. Tankless Model- Waterdrop WD-G2 P600 RO, Check price on Amazon

The Waterdrop G2 P600 is a tankless under sink RO system that removes most contaminants, including salt, TDS, fluoride, nitrates and heavy metals from water.

With a fast flow rate of 600 gallons per day, this unit can fill a glass of water in 8 seconds. It also produces less waste water. Dispensing 2 cups of filtered water will produce 1 cup of waste water.

G2 600 is an affordable choice as it reduces the cost of filter replacement and upgrades. Compared to conventional models, this unit saves 600% more water.

The system also boasts automatic shut-off valves, which reduce the risk of leakage. It also comes with a filter life indicator that reminds you to replace the filters on time.

2.Alkaline Remineralization iSpring RCC7AK¬UV, Check price on Amazon

The iSpring RCC7AKUV is a 7-stage water filtration system that filters up to 99% of over 1,000 contaminants including chlorine, lead, arsenic, asbestos, calcium and sodium from the water.

With its 11 watts UV stage, this system can deal with all kinds of water like well water and water from other unreliable sources like streams and lakes.

The unit comes with an alkaline remineralization filter that restores healthy minerals and maintains a natural alkaline balance. The AK filter also helps improve the taste of your water.

Quality components ensure low maintenance and reliability, while a clear see-through first stage housing makes filter inspection easy.

3. Budget Option- Whirlpool WHER25 RO Filtration System, Check price on Amazon

If looking for a budget under sink RO system, try WHER25. The 3-stage system reduces sediment, cysts, chemicals, chlorine taste and odor, lead and dissolved solids from water.

The system’s filters have an extra-long life and are easy to remove and replace, thanks to the Ultrarelease technology.

The unit is NSF certified, and 3rd part tested to ensure that it performs as advertised. It is also easy to install with simple DIY skills.


When going for an under sink RO system, be sure to consider not only the buying price but also the installation and maintenance cost. This will help you get a precise estimate of the amount of money you’ll have to part with(1).

Actually, you don’t necessarily have to go for higher-priced systems because they work ‘better’. You might be surprised to find a lower-priced unit that works in the same way. So, a higher price doesn’t always translate to better performance.

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