Cloud RO Review: A Data-Driven Analysis

We tested Cloud RO (or Cloud, for short) to assess its ability to purify our municipal water in a townhome in Denver, Colorado. In this review, we’ve summarized our objective data and subjective analysis across a range of performance categories, including contaminant reduction, ease of setup, maintenance requirements, efficiency ratio, and more. 

Overall Score: 9.24

How We Test & Score

9.42 Contaminant Reduction

10.00 Design

10.00 Maintenance

8.50 Filtration Rate

7.50 Setup

9.20 Company

What We Like

Greatly reduced or removed 10 contaminants with health effects in our water

NSF performance certified for TDS reduction

Easy to install

App makes it easy to track filter life & replacing filters is quick and affordable

Smarter, more efficient, & more space-saving than other conventional RO systems

Built-in remineralization filter

What We Don’t Like

Not certified to reduce specific contaminants of concern

Additional maintenance required to replace the battery

Expensive

Price	$599
Contaminants Reduced	200+
Certifications	NSF 58
Process	Carbon + Reverse Osmosis + Remineralization
Filter Capacity	Pre/Post Filters 500 gallons, RO membrane 1,500 gallons
Annual Cost	~$200
Warranty	1 year

View at cloudwaterfilters.com

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📊 Scoring Data

Cloud RO is a conventional tank-based RO system, but with a modern twist. To accurately compare it to the other best under-sink RO purifiers we’ve tested, we comprehensively evaluated the system’s features and performance across six key scoring categories, which, when combined, gave us an overall averaged performance score. 

We also measured several factors that are unique to RO systems, such as efficiency ratio, recovery rate, and noise output, but these aren’t currently included in the overall ranking.

You can see our scores for Cloud RO in the table below.

Criteria	Results
Overall Score	9.42
Health Related Contaminants	99
Aesthetic Related Contaminants	35
Performance Certification	Certified for 16% of reduction claims
Filtration Rate	80 GPD
Component Quality	Exceptional
Component Certification	Certified
Setup	Below Average
Servicing Requirements	Exceptional
Costs	$0.18/ gallon
Warranty Length	1 year
Shipping	Free on all orders in the US
Returns	12 month guarantee

🎬 Video Review

🚰 Contaminant Reduction

Score: 9.42

There were two scores that influenced the overall score for contaminant reduction in our testing: 

1. The data we received from our own water quality testing
2. Performance certification data (or lack thereof)  from official testing organizations 

We combined these to obtain our overall contaminant reduction score. This is fairer than only using our own testing data, which has limitations: we can only test a product’s ability to remove the contaminants in our own water, so evidence of certifications allows us to confirm a filter’s proven ability to reduce additional contaminants. 

Our Performance Testing

Score: 9.58

We tested Cloud RO twice with two different municipal water supplies in Colorado. To get the most accurate and comprehensive results, we sent samples of our water to a testing company, SimpleLab Tap Score, to conduct analysis in laboratory conditions. 

We took our pre-filtered water samples straight from our faucet. After installing and using Cloud RO for three weeks, we then took our filtered water samples from the dedicated RO faucet.  

Health-Related Contaminants

Score: 7.70

Test 1

In our initial water quality tests, our source water was already moderately clean, with a TDS reading of 76 PPM.

Post-filtration, our results showed that the Cloud RO had removed 100% of both disinfection byproducts and fluoride, which is exactly what we’d expected from an RO purifier. It also eliminated aluminum, copper, manganese, molybdenum, and strontium, and greatly reduced barium (by 78%) and sulfate (by 94%). 

Test 2

When we repeated testing for Cloud, we used a different water supply that was highly contaminated, with a TDS reading of 707 PPM — that’s almost 10x the dissolved solids concentration of our test 1 water source.

Barium, nitrate, nitrite, three disinfection byproducts, total chromium, copper, molybdenum, fluoride, manganese, boron, and uranium were among the contaminants with health effects detected in our baseline sample. 

All three DBPs were detected above the HGL: 10.3 PPB of dibromochloromethane was detected, exceeding the HGL of 0.1 PPB, along 8.01 PPB of chloroform and 4.38 PPB of bromodichloromethane, both exceeding the HGL of 0 PPB. 

Uranium also exceeded the HGL: 0.0118 PPM of this contaminant was detected, while the HGL is 0 PPM. 

See the full list of contaminants and their concentrations in the next table. 

Interestingly, our data showed that Cloud actually performed better on a percentage basis when it was challenged with a more contaminated water supply. 

It completely eliminated fluoride, all three disinfection byproducts, uranium, copper, strontium, selenium, manganese, potassium, molybdenum, and nitrate. All these contaminants were non-detectable in our RO water sample. 

It also greatly reduced barium by 97% (to 0.00069 PPM), sulfate by 95% (to 7.7 PPM), and total chromium by 93% (to 0.00021 PPM). No contaminants remained in concentrations exceeding the HGL.

The big advantages here are the complete elimination of fluoride and disinfection byproducts. Not all of the RO systems we’ve tested have been able to effectively remove fluoride — but we know that fluoride reduction is important for many folks considering RO, since standard water filters usually struggle to address this contaminant. 

DBPs reduction is important if you’re on a chlorinated water supply, helping you avoid the long list of concerning health effects related to these chemicals, including reproductive abnormalities, liver and kidney damage, carcinogenic effects, developmental consequences, and growth inhibition.

Test 2 Limitations

There were a number of contaminants that Cloud RO was unable to remove completely. We saw weaker reductions of:

• Boron, by only 26.6% (from 0.41 PPM to 0.301 PPM). This is actually expected, since boron exists as uncharged boric acid at neutral pH and slips through RO membranes. Essentially, no residential RO system handles boron well, and we noted similar results with other systems we tested.
• Nitrate, by only 48% (from 2.5 PPM to 1.3 PPM). This is lower than the typical RO nitrate rejection we’re used to seeing, which is usually 83-95%. But in this batch of testing, many units struggled to remove nitrate, likely because our water temperature and pressure were lower than recommended for RO filtration.
• Vanadium, by just 50.7% (from 0.00118 PPM to 0.000582 PPM). This looks like a relatively low reduction, though it’s worth noting that our initial baseline concentration is already very low.

Given our test water conditions and boron’s known status as a contaminant that RO struggles to remove, none of these results were surprising. 

Aesthetic Contaminants

Score: 3.50

An unexpected outcome of our testing was that Cloud received a low score of 3.5 for aesthetic contaminants. 

The system did a great job at reducing 100% chlorine, the most common aesthetic contaminant in treated tap water. But the presence of chlorine doesn’t affect Tap Score’s own scoring because the contaminant isn’t tested by the lab (we tested for it ourselves using the provided DIY test strip due to chlorine’s volatile nature). 

So what brought down the aesthetic score in our purified water test results?

The Tap Score algorithm lowered the aesthetic score due to the purified water’s high alkaline pH (9.7 in Test 1, and 8.7 in Test 2). This is actually a selling point of the system because it demonstrates its ability to remineralize water and increase its pH (many folks spend a lot of money on bottled water with a high pH). 

However, the Tap Score algorithm is affected by high pH water because, according to the lab, it “may cause a bitter or baking soda-like taste, leave deposits on your fixtures, and have a slippery or soapy feel”.

Luckily, you don’t need to worry about deposits on your fixtures from a point-of-use RO system that has its own faucet, and we didn’t notice any negative taste or texture effects after installing the unit. 

Minerals & Salts

That brings us onto the topic of the minerals and salts concentrations in our water. This testing sub-category isn’t something that we currently assign a score to, but it’s definitely worth a mention when we’re talking about reverse osmosis systems. 

RO units purify water, which means they remove everything, including minerals and salts that give water a pleasant alkaline taste and contribute to its pH. 

A great feature of Cloud RO is its built-in remineralization filter, so it adds these minerals back into the water. 

The manufacturer claims that the minerals reintroduced by the remineralization filter are calcium, magnesium, potassium, sodium and trace minerals, which “naturally elevate” the water’s pH and make it more alkaline. 

However, we found that in both tests, all minerals associated with alkalinity were greatly reduced:

In Test 1, calcium was reduced by 93%, magnesium by 55%, potassium by 100%, and sodium by 90%. 

In Test 2, calcium was reduced by 99%, magnesium by 68%, potassium by 100%, and sodium by 92%. 

These percentage reductions are pretty consistent, despite our water in Test 2 being significantly more contaminated. 

Mineral and alkalinity reduction is actually quite a common outcome that we’ve experienced when testing RO systems with an alkaline post-filter. It seems that even though the filter reintroduces trace minerals back into the water, the concentrations of minerals added aren’t equal to those reduced, which means there’s still a mineral reduction overall. 

But we still know that the remineralization filter is effective in this system because the pH of our water increased slightly, from 8.4 to 9.7 in Test 1, and from 8.0 to 8.7 in Test 2. Demineralized RO water generally has a low pH of 6.0-6.5 due to its lack of minerals, so it’s great to see the remineralization filter working to mitigate the effects of mineral loss here. 

TDS & TDS Creep

Our Tap Score data gave us a helpful insight into Cloud’s effect on TDS when purifying our water. Interestingly, across our two samples with baseline TDS ranging from 76 to 707 PPM, the system reduced TDS by 81.6% to 90.4%, with higher removal rates on the more contaminated source water.

We also wanted to see how the system affected TDS at different phases of use, and whether or not TDS creep was an issue. For this, we measured TDS ourselves on-site using our own TDS meter. 

You can learn more about this in our guide to TDS creep, but the basic premise is that when a reverse osmosis system isn’t used for a short period, it causes the pressure in the semi-permeable membrane to equalize, raising the TDS levels in the initial draw of filtered water.

Our baseline unfiltered water had a TDS reading of 657 PPM. The WHO classifies water with a TDS reading of 600 to 900 as “poor”, because of how it might affect taste. 

We measured TDS creep by leaving the system to sit idle overnight for 10 hours, then opening the faucet and filling a glass of water with the first draw sample. 

Cloud has a dedicated solenoid valve, which shuts off water flow once optimal volume has been reached in the tank, boosting faucet flow rate while preventing TDS creep (in theory). So we expected that TDS creep wouldn’t really be an issue with this system.  

But in our tests, Cloud had a 1st draw TDS reading of 284 PPM. At first glance, this is indicative of TDS creep, especially when we compared it to our second draw sample reading, which we took after running water through the system for 2 minutes: 68 PPM. But when we spoke to our contact at Cloud, they explained that this “TDS creep” was actually caused by minerals leaching from the new remineralization media:

“When a new Cloud system sits overnight, the product water becomes saturated by the minerals in the post filter, which causes the spike you saw in TDS. This is not due to TDS creep and will actually normalize after a few weeks of use.“

 Additionally, the effect is short-lived, and as our second reading shows, TDS levels drop back down quickly once the system is running.

Performance Certifications

Score: 8.00

In this updated review, we’re happy to report that the manufacturer has now obtained an NSF 58 certification for TDS reduction. This had been applied for when we published our previous version.   

While we think any certifications are better than none for the reassurance they can provide for performance quality, this isn’t the most impressed we’ve been with a product’s certifications. Cloud RO didn’t get the top score here because it’s only certified to reduce one of the six contaminants listed on the product page (lead, fluoride, PFAs, pesticides, pharmaceuticals, and TDS), or 16% of the manufacturer’s overall reduction claims.

TDS reduction is all well and good, but it doesn’t tell us which specific contaminants the system can reduce. We’d prefer to see certifications for the reduction of contaminants with harmful health effects, like lead, PFAS, and chromium-6. 

🚦Filtration Rate

Score: 8.50

The water production rate for reverse osmosis systems is measured in GPD (gallons per day), and the filtration rate for Cloud is 80 GPD. 

Is this the best GPD rating we’ve seen? No. We’ve seen RO systems that can deliver up to 600, 800, or even 1,000 gallons per day – although this is really nothing more than a number, since the average family of 4 drinks just 2 gallons of water per day. 

Let’s also not forget that flow rate is less important in this system than it would be in a tankless RO unit because when you turn on the tap, you can access water that’s stored in the tank rather than having to wait for it to flow through all the filtration stages before reaching your faucet. 

The tank holds 3.2 gallons, so it’s unlikely that you’ll leave the faucet on long enough to empty it in one go, and the tank will be replenished between uses.  

In our own flow rate testing, at a feed water temperature of 57.5°F and a static water pressure of 50 PSI, we measured the time it took (in seconds) for the unit to fill a graduated measuring container up to a specified fill line with purified water. 

We wanted to measure our timings as accurately as possible, so we recorded the process on camera and uploaded the footage onto an editing tool. We then moved through the video frame by frame until we had the precise starting point (water leaving the faucet) and the exact ending point (container filled to the specified fill line)

Using this process, we measured the average time to fill to the 12-ounce line of our jug, then repeated the same test 2 additional times. The average time we recorded was 124.29 seconds, translating to a flow rate of 0.05 GPM (gallons per minute), or 2.72 GPH (gallons per hour).

That’s approximately 65.17 GPD (gallons per day), which is slightly behind the manufacturer’s claimed purified water production rate of up to 80 GPD. Since our feed water temperature and pressure were lower than the recommended 77°F and 50-80 PSI, this likely impacted water flow in our tests. 

Efficiency Ratio

Conventional tank-based RO systems have a pure-to-wastewater ratio of 1:4, meaning that for every 1 gallon of pure water produced, 4 gallons are wasted. 

Unfortunately, there’s no avoiding wastewater in the RO process – it’s just how it is. But many systems are becoming more efficient, and Cloud is one of them, with a much-improved efficiency ratio of 1:1. That means only 1 gallon of water is wasted for every 1 gallon purified. 

We conducted our own testing to see how the system’s claimed pure-to-waste ratio compared to our recordings from real-world use. This involved unhooking the end of the wastewater line and placing it inside a 1-gallon measuring cup. We then turned the system on and collected 12 ounces of purified water in a separate cup. The volume of wastewater produced during this time was recorded.

Cloud RO produced 16 ounces of wastewater for the 12 gallons of water purified, which equates to approximately 1:1.3 (meaning that for every 1 ounce of purified water, about 1.3 ounces go to drain). That’s pretty close to the manufacturer’s claimed 1:1 efficiency ratio.

Again, our lower-than-recommended water temperature and pressure likely affected the system’s efficiency by slowing the flow of water through the RO membrane and, in turn, increasing drain flow.

We then repeated this test, with a small difference: we measured the volume of wastewater produced when dispensing a larger volume of 64 ounces of purified water. This time, 66 ounces of wastewater were recorded, equal to a pure-to-wastewater ratio of approximately 1:1.03. That means for every 1 ounce of water purified, 1.03 ounces of water goes to drain.

You can see that with our smaller-volume test, Cloud is slightly more efficient. Most likely, this comes down to a difference in backpressure on the RO membrane. 

When you first start using an RO system to purify water after a period of inactivity, it has water on both sides of the membrane, which causes the pressures to gradually equalize across it. The membrane can’t immediately start operating at complete differential pressure, which means that more water goes to drain relative to the purified product when you turn it on. 

That’s why, when we collected just 12 ounces of purified water, more water went to drain compared to the volume of water purified. But when we took the larger 64-ounce draw, the system had time to stabilize and operate at its slightly better recovery rate.

Water waste is something that you will need to be comfortable with when buying any reverse osmosis system. If you don’t want to waste any water at all, you’ll have to consider a standard, non-RO under-sink water filtration system, but then you won’t get the perks of purifying your water.

📐 Design

Score: 10.00

Cloud RO is a modern, smart take on a conventional tank-based RO system. This compact unit features a small 3.2-gallon water tank, which stores purified water, giving you faster access to the water you need when you turn on the tap.

The system comes with a dedicated faucet (available in four finishes). You can access RO water when you need it, and use your normal faucet when you don’t need purified water (such as for washing the dishes), so you don’t use the filters unnecessarily. 

The factors that affected Cloud’s overall design score were:

1. Its component quality (based on our own subjective analysis). 
2. Whether or not it had a materials safety certification (based on objective data). 

Component Quality

Score: 10.00

Cloud got the top score from us for component quality. It’s made from BPA-free food-grade plastic and comes with a lead-free, stainless steel faucet, ensuring your purified water won’t get recontaminated on its journey into your glass. 

From first impressions when unboxing the system, it has a more premium quality and presentation than many other conventional RO units we tested, from its packaging to its components.

For instance, there’s minimal plastic packaging, with the bags holding the different components made of cloth. There are also far fewer loose components than other conventional ROs, which simplified the installation process. The three-way shutoff is stainless steel, and his a 1/4 tubing quick connect (the first we’ve seen like this — other systems typically have a nut to connect the tube). Again, this points to a higher quality design. 

The system feels sturdily built, and we appreciate that all the filters are housed in a solid box (which the manufacturer calls the “magazine”), so there are no flimsy components on the outside. The unit base holds the filter unit and contains sensors and a permeate pump.

Smart Features

Like many modern RO systems, Cloud has a few smart features that you might enjoy or find useful. 

You can connect the unit to a mobile app and view tracking data thanks to its built-in sensors. Data includes water consumption (tracked by the pressure sensors), tank volume, and water filter lifespan.

Certification

Score: 10.00

Cloud has a materials safety certification as a component of its NSF 58 performance certification, so it received the best score in this category from us. 

Filter Materials & Media

There are four filters in the Cloud RO unit:

• Sediment Filter: Traps dust, rust, dirt, and other debris and sediment that could clog the later filter stages. The filter has a 5-micron rating, meaning that it traps contaminants down to 5 microns in size.
• Activated Carbon Block & Anti-Scale Filter: Combines adsorption (from the 1-micron activated carbon media) to reduce chlorine, tastes, and odor, and an anti-scale media, which protects the RO membrane from limescale damage.
• Reverse Osmosis Membrane: Uses DOW filmtech technology to reject the majority of impurities while allowing water molecules to pass through. 
• Remineralization Post Filter: A coconut carbon block filter with a blend of three different media to add healthy minerals to water, boost its pH, and polish water before it’s delivered to the tank for storage. 

The four filters are housed in plastic cartridges.

⚙️ Setup

Score: 7.50

Installing any reverse osmosis system is relatively tricky – you’ll need to plumb the system into your main water line and hook up a drain line to carry the wastewater into the closest drain. These are two extra installation requirements for RO systems only.

But we found it easier to install Cloud RO than conventional under-sink tank-based RO systems, thanks to its compact, simplistic design, with many of the connections pre-installed out of the box.

Installation Challenges

The most challenging part of the installation process was drilling the hole in the granite countertop for the faucet, but with a diamond-tipped drill bit (which we ended up buying for this purpose), it was no big deal. But the faucet itself is easy to install and has a metal push-to-connect male piece on the bottom. The nut has wings for hand tightening.

We also had to drill a hole above the p-trap in the sink drain for the drain line, but again this was pretty easy. The rest is simply plugging all the plumbing together, which was really easy following the instructions in the user manual. There’s also a handy video installation guide on the Cloud website if you’re more of a visual learner. 

Installation Benefits

What we particularly appreciate about this system’s design is that the base is detachable from the main unit body, so you can install the base alone without having to work around the bulk of the filter unit, then simply attach the unit once you’ve finished. Plus, all the fittings and filters are pre-installed, so you don’t have to waste your time putting the unit together like a jigsaw puzzle before you can start with installation. 

Another benefit of Cloud RO’s design is that you don’t need to plug the unit into a power supply because its internal sensor tech is powered by the battery pack. That means you have more leniency when it comes to your install location as it doesn’t need to be within a certain distance of a power socket. 

Some other benefits we noted from the installation include: 

• The drain saddle comes pre-installed on the tubing, so no effort is needed to do this yourself.
• Each tube is clearly labeled, so it’s obvious where everything needs to go.

• The entire system takes up far less space under the sink than others, since the tank is designed so it can “stack” with the main body of the unit, sitting behind.

Still, you’ll need DIY know-how and some basic plumbing knowledge to install this system, and that’s why it received a slightly lower score from us in this category. You might need to enlist the help of a friend or a family member if you’re unsure. 

We noted a total of 14 leak points at the fittings—that’s the number of opportunities for the unit to leak at any point during its operation.

After finishing the install, we followed the instructions in the user manual to flush the unit. This initial flush took around 6 hours and 15 minutes and involved filling three full tanks of water before we could start using the system. 

Noise

After installing Cloud RO, we used a phone app to measure the noise emitted from the unit while in operation. 

We recorded sound decibels from the system at 1 foot and 3 feet away. At 1 foot, Cloud produced 29.0 decibels, and at 3 feet, it produced 28.9 decibels. That’s very quiet, equivalent to a soft whisper or rustling leaves. It’s what we expect for a conventional RO system that doesn’t use an internal pump. 

🔧 Maintenance

Score: 10.00

We awarded Cloud’s maintenance score by combining our scores for its servicing requirements and ease of maintenance. 

Servicing Requirements

10.00

We found that Cloud’s filter tracking features and app made maintenance about as easy as it gets for a system of this kind. 

We could use the app to know the system’s filter and battery status at a glance, as well as get a reading of our water’s TDS (a higher-than-optimal TDS count indicates that one or several of the filters need to be replaced).

Swapping out the filters is easy and can be done as recommended by the app. The only maintenance aspect we identified that you might consider a negative is that you’ll also need to replace the battery as well as the filters, which is an extra job and expense. But the battery lasts 1.5+ years, and you’ll receive a new battery pack with your replacement RO membrane, so this isn’t a big inconvenience.

Costs

Score: 10.00

We estimated that the ongoing spend for Cloud RO is around $0.46/ gallon, equating to a total annual cost of $500, and a 5-year ownership cost (including the cost of the upfront purchase) of $3,099.00. This is based on the combined maintenance cost of all four filters and the battery pack in the system.

As we mentioned, the system has internal sensors that track and suggest filter changes based primarily on your water usage (i.e. the volume of water flowing through the system), as well as incoming water hardness/TDS, post-RO hardness/TDS, and pressure changes over time.

The pre and post-filter typically need to be changed every 6 months, and the RO membrane and battery typically need to be changed every 18 months, which is about average for a point-of-use RO system.  

🏢 Company

Score: 9.20

The Cloud RO unit will set you back at least $550 (depending on whether there are any promotions or sales running at your time of purchase). 

Since you’re making a substantial investment, you want to know that you’re buying from a reliable company. We’ve evaluated Cloud Water Filters as a manufacturer in this section. 

Warranty

Score: 8.50

Cloud RO is backed by a 1-year warranty against mechanical issues, defects, and performance/cosmetic flaws due to improper manufacturing. If you make a claim that’s covered by the warranty, you’ll receive replacement components as needed.

You can view the warranty terms on the product FAQ page here. 

Shipping 

Score: 10.00

Cloud Water Filters offers free shipping throughout continental U.S., including Alaska and Hawaii. If you live in Canada, the manufacturer recommends contacting them at [email protected]. Shipping takes around 2-3 weeks from your order date. 

Returns

Score: 10.00

The returns period for Cloud RO is the exact same as the warranty period: 1 year. All customers are entitled to a 100% money-back guarantee, so if you’re unsatisfied in any way or just don’t like the unit, you can return it for a full refund. 

This is a longer returns period than we’re used to seeing, and it’s also a big bonus that there’s no restocking fee, so you truly do get your money back. If you’re a little unsure about spending a lot of money on a system, Cloud’s returns policy means you can essentially test it out without having to commit to the purchase. 

💰 Value For Money

To finish this review, we want to weigh up Cloud RO’s pros and cons and comment on its overall value for money. 

The system is costly upfront, although it’s not one of the most expensive POU reverse osmosis units we’ve come across. After extensively reviewing its features, we think it’s worth the money you pay upfront, especially given that replacing the filters is affordable in the long run. Across our two independent lab tests with baseline TDS ranging from 76 to 707 PPM, Cloud eliminated most contaminants and reduced total dissolved solids by 81-90%. It performed exactly as we’d expect from an RO system, with certifications to support its contaminant reduction and design quality.

However, value for money depends on your own personal situation, including what you are comfortable spending on a water filtration system, whether you’re on board with the RO water treatment process (including the setbacks of water waste and mineral loss), and the value you place on purifying your water.

If you’re keen to reduce as many contaminants as possible from your water and you want a smarter version of the conventional under-sink RO concept, you’ll probably find that Cloud is great value for money.  

But if you’re not bothered about those additional smart features and company perks (i.e. a great warranty and guarantee) and you don’t mind using a clunkier, less efficient system, you can buy cheaper alternatives that use the same concept but may not offer the same quality of performance. 

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