The Complete Guide to Tankless Reverse Osmosis Systems

Tankless RO systems are about ⅓ the size of standard RO systems, twice as easy to install, and give you hundreds of times more water than regular filters. 

Seem too good to be true? We thought the same thing at first, too, so we got to work researching and testing tankless reverse osmosis systems. In this article we’ll give you the info you need to help decide whether a tankless reverse osmosis is best for your home.

What is a Tankless Reverse Osmosis System?

Like the name implies, a tankless reverse osmosis system is an reverse osmosis system that operates without a tank.

Aside from the physical size and requirement of a tank, both tankless systems and those that use tanks function in the same way: your tap water passes through each filter inside of the system to help clean it beyond simple carbon filters. In fact, they have identical filters, from carbon block filters that help with large particles, to GAC filters and RO membranes that help scrub your water of bad tastes and smells.

While there some pretty important advantages tankless systems have over systems that use them, at the end of the day they operate in the same way. Their similarities are what make them great for any household, but their differences are what make tankless RO systems great for every household.

Types of Tankless Reverse Osmosis Systems

Like other RO systems, tankless RO systems come in different styles. They all essentially have the same functions, but they’re shaped in different ways and can serve different purposes.

  • Horizontal (Sitting) Tankless RO Systems like the NU Aqua Efficiency Series Tankless Reverse Osmosis System lay on the floor under your sink and only take up around 8x8x12in. (LxWxH) of space. With front loading filter cartridges, these systems are perfect for any household, whether you’ve got plenty of room underneath your sink or just enough.Horizontal (Sitting) Tankless RO Systems vs Vertical (Standing) Tankless RO Systems
  • Vertical (Standing) Tankless RO Systems like those you find from Waterdrop stand up straight like standard RO systems, but they’re only around 17x6x14in. These systems are great if you have at least 16” of space under your sink. From there, all you need is about 7” of room between the system and your plumbing, which is pretty standard for most households. Their filter configuration can vary from system to system, but mostly come in two styles:
    • Front loaded cartridges like those in horizontal tankless RO systems.
    • Top loaded cartridges like those in vertical tankless RO systems that require you to remove the top of the system to replace the filters.

Technically, countertop filters or whole house filters as “tankless” systems. While these are technically tankless by nature, they're not what we're referring to here

Advantages of Tankless RO Systems

Tankless reverse osmosis systems may be smaller than other 3+ stage RO systems you’re used to seeing, but they give you the same high quality filtration. Not only that, but as we’ve mentioned, tankless systems actually perform at a higher rate than larger systems. But how?

Strange to think that you could get better filtration out of smaller filters than larger ones, so let’s take a look at the facts about tankless RO systems to prove the point: 

High Quality Water With Unbelievable Efficiency

In terms of quality, these compact units can do just as great of a job filtering your water as any larger RO system. However, by getting rid of the need to fill a tank, tankless reverse osmosis systems give you virtually unlimited reverse osmosis water at much faster speeds compared to standard RO systems

Without water being redirected to a storage, tap water is scrubbed through multiple filters and flows directly to your faucet. This creates a direct line of water to your faucet instead of an indirect one to a tank, which increases the amount of water you can get at a time. While most tankless systems are rated anywhere from 400-600GPM or higher (at least 4-5x higher than traditional RO systems), the truth is that tankless RO systems give your virtually unlimited gallons of water per minute.

Most- if not all- tankless RO systems have booster pumps, too. If your water pressure isn’t so great, it’ll take a while for it to be filtered through each filter, slowing the rate it comes out of your faucet. Worse, without the right pressure, your filters won’t be able to do their job as efficiently, so your water may not be as filtered as it could be at higher speeds. Tankless systems already have them installed, so you’ll get the filtration you expect at a flow rate that’ll please anyone. 

Easy Installation & Maintenance

With very few exceptions, tankless RO systems are hands down the easiest reverse osmosis systems to install and maintain. From set up to filter chances and upkeep, tankless systems are simple to install, maintain, and use.

Installation requires little more than some plumbers tape and a power drill. You connect simple tubing into a single RO unit (usually no more than about 5), connect that to your pipes, install the faucet, and you’re ready. Compare that to larger RO systems that require lots of tools, tubing, drilling, and additional mounts to get started, tankless systems are much easier to set up.

Structurally, tankless RO systems are much easier to work with than other systems. Most tankless systems have a cover you flip up or remove to gain access to filters. When changing filters out, all you do is twist to unlock them and click into place when you’re finished. Compare that to other RO systems that require special tools to take off thick filter housings, you’ll find tankless filters are exponentially easier to swap out when the time comes.

NU Aqua Efficiency Series Tankless 600GPD Reverse Osmosis System 2:1 Pure To WasteTechnologically, tankless systems also make upkeep a breeze by using two features: an on-board display and a smart faucet.

  • On-board LCD displays will show you the health of your filters, with different colors indicating the life of each one of them. When it’s time to swap them out, a light will show a color to let you know it’s time for a filter change.
  • Smart faucets are faucets with color indicators or digital displays. These alert you of drops in water quality so you can look into the health of your filters. Whether it’s a single light or a whole display, these will show you when it’s time to swap out filters before your water starts tasting bad.

Some systems come with both, and others only come with one. Whichever system you choose and whichever indicator it comes with, tankless systems save you the hassle of finding out the hard way (the ol’ taste test) that your filters need to be changed.

Compact, Space Saving Design

Tankless reverse osmosis are smaller than their tanked counterparts. They take up less than 18in. (1.5ft.) of room in any direction, and aren’t much wider than 8in. Now, that may seem like it’s around the same size of any other RO system, but here are a couple considerations when it comes to sizing filters underneath your sink:

  1. Tanks are about 11x15in. (DxH). Systems like 5 stage RO systems from Nu Aqua are around 18x5.5x12”, so add a tank to that equation and you’re looking at a system with a total measurement of around 18x16.5x15”. That’s over a foot in all directions compared to a tankless system.
  2. Additional filters- alkaline filters and UV’s, and polishing filters- all add at least 3in. of height each. A 5 filter RO system can be as tall as 18” but a 6 or 7 filter system can be nearly 2ft. tall.

Not only do tankless systems save room under your sink, their size is what facilitates the other advantages of these systems. Tank systems take longer for water to pass through each filter, which hinders the speed you receive water, and ultimately how much water you receive in each day. By being so compact and removing the need of a tank, these systems streamline the reverse osmosis process and send filtered water straight to your tap faster than ever. 

Much less waste water

By streamlining the process of filtering water, you don’t create as much waste water and you don’t waste as much water, either. All systems waste water, but tankless systems don’t create as much wastewater or waste as much in the process. In fact, tankless systems offer 2:1 pure water to waste water ratio, whereas standard RO systems give you a 1:3 pure to waste ratio. 

Systems with tanks take in lots of water in order to fill a single tank. Once that tank is full, the rest of the water that isn’t filtered is then sent to the drain line and flushed out. If you filter lots of water but only a limited amount of it can be stored, you end up wasting a majority of the water you just filtered, along with the contaminants you just filtered out.

Tankless reverse osmosis systems, on the other hand, only direct waste to your drain line. That means nearly every drop of tap that enters the system is filtered and comes out of the faucet.

Are Tankless Systems Right for Your Home?

If you’re wondering whether a tankless reverse osmosis system is right for your home, ask yourself how much water you’ll need at any time, and what type of filtration you’re looking for.

If you have multiple people in your home, though, or you consume lots of water in general, tankless systems will do so with consistent water pressure level while the system is running.

In all fairness, though, while tankless systems are efficient, they do have their limitations. Mainly, that you can’t add UV filters to help against living organisms in water, or alkaline filters to help remineralize your water. For those types of filters you’ll need a larger system that will more than likely use a tank.

Now, if you’re looking for the water filtration only reverse osmosis can give you, but want to save room under your sink and a lot of hassle in the process, a tankless system is perfect for your household. They’re easy to install, simple to maintain, and most important they’re more efficient than most of their larger counterparts.

Didn’t expect that sort of filtration out of such a small system, did you?

Leave a comment

All comments are moderated before being published

Featured products

Save 17%
NU Aqua Platinum Series 5 Stage 100GPD RO SystemNU Aqua Platinum Series 5 Stage 100GPD RO System
NU Aqua Platinum Series 5 Stage 100GPD RO System
$149.95 $179.95
In stock