Waterdrop X Series Reverse Osmosis System Review

We tested the Waterdrop X Series X12 to see how effectively it could purify our municipal water in Westminster, Colorado.

This review is a comprehensive summary of our observations from our subjective and objective data, gathered during our hands-on testing of the system’s contaminant reduction, efficiency ratio, design quality, ease of setup and maintenance, and more.

Overall Score: 8.42

How We Test & Score

7.83 Contaminant Reduction

9.70 Design

10.00 Maintenance

10.00 Filtration Rate

7.00 Setup

8.85 Company

Note: There are three system configurations in the X Series. We tested the X12 model

What We Like

Greatly reduced or eliminated most contaminants with health effects in our water

IAPMO performance certified for TDS reduction

Excellent 1,200 GPD filtration rate

Easy & affordable to maintain

Space-saving tankless design

Built-in remineralization

What We Don’t Like

Introduced antimony into our filtered water

Fluoride, sulfate, & strontium weren’t reduced by as much as we’d hoped

High upfront cost not justified by features/performance 

Price	$1,200
Contaminants Reduced	1,000+
Certifications	NSF/ANSI 58
Process	Mechanical + Carbon + Reverse Osmosis + UV + Remineralization
Filter Capacity	1,100/ 550/ 2,200 gallons
Annual Cost	~$173
Warranty	Lifetime

View at waterdropfilter.com

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📊 Scoring Data

The Waterdrop X Series X12  is one of the more expensive tankless under-sink RO systems we’ve tested, and we wanted to evaluate its features and performance thoroughly to understand what we were paying for, and ultimately determine its overall value for money.

For all the filtration systems we test, we refer to 13 specific scoring categories, which we can then compile into a single overall weighted and averaged score. Below, we’ve shared this key scoring data of the X12 model. 

Criteria	Results
Overall Score	8.42
Health Related Contaminants	77
Aesthetic Related Contaminants	99
Performance Certification	Certified for 7% of reduction claims
Filtration Rate	1,200 GPD
Component Quality	Outstanding
Component Certification	Certified
Setup	Weak
Servicing Requirements	Exceptional
Costs	$0.14/ gallon
Warranty Length	2 years
Shipping	Free shipping to lower 48 US states
Returns	30 days

🎬 Video Review

🚰 Contaminant Reduction

Score: 7.83

We assessed the Waterdrop X Series’ contaminant reduction by conducting our own water testing at home. The overall score in this category was also influenced by official performance certification data that supported Waterdrop’s contaminant reduction claims. 

Our Performance Testing

Score: 7.81

We use a lab testing service called SimpleLab Tap Score to test our water for our reviews. 

We’ve found that Tap Score’s test results are delivered in the most comprehensive and user-friendly format, and their strict sample-taking protocol helps us ensure our results are as accurate as possible. 

We took two water samples: one straight from our kitchen faucet, and the other from the X12 dedicated faucet.

Health-Related Contaminants

Score: 7.70

The Waterdrop X12 received a poorer score for Health-Related Contaminants than most of the other reverse osmosis systems we’ve tested. 

Before we talk about what brought the score down, let’s start with the positives. 

Contaminants Reduced Completely

14 contaminants with possible health effects were detected in our water, including three types of disinfection byproducts, lead, fluoride, uranium, and other heavy metals. 

The three disinfection byproducts (chloroform, dibromochloromethane, and bromodichloromethane), as well as lead and uranium, were all present above Tap Score’s HGL. We were particularly keen to remove these contaminants from our water, especially lead, which is toxic at any concentration.

And the good news is that the Waterdrop X12 reduced 100% of all these contaminants that exceeded the HGL.

It also reduced 100% of cobalt, copper, molybdenum, and zinc.

Unexpected Results

There was one outcome that affected the overall score in this category: 0.00299 PPM of antimony, a metal that has been linked to liver, blood toxicity, and blood sugar effects, was detected in our filtered water when it hadn’t been present in our unfiltered water sample. 

These concentrations exceeded Tap Score’s HGL of 0.001 PPM by 195%. 

Our hypothesis is that the antimony was introduced either from the filters themselves or the internal plumbing in the system. Something you may not know about this metal is that it’s often used as a catalyst in the production of certain plastics, especially PET. In our research, we found numerous studies that observed antimony leaching from PET plastics into bottled water:

• This 2008 study in Water Research tested the antimony concentrations from nine commercially available bottled waters in the southwestern US. 0.095 to 0.521 PPB of antimony was detected in the water, well below the EPA’s MCL of 6 PPB, but exposing the bottled water to high temperatures above 50°C (140°F) increased the rate of leaching “significantly”.
• This Kuwait University study on the migration of antimony from PET into commercial bottled water in Kuwait noted a “low rate of leaching” in bottled water stored at room temperature, but observed that at temperatures of 50°C (122°F) and above, antimony release into water “can occur very rapidly”. 

Both these studies have something in common: they found that antimony leaching occurred from PET plastics regardless of temperature, but was more rapid at a higher temperature.

We reached out to Waterdrop and their customer support ensured us the internal system components are made of polyethylene (PE) – not PET.

We can’t say for certain that this outcome would be expected from the internal components of an RO system, but wanted to present plastics as another potential source of antimony.

We’d need to conduct more testing and analysis to confirm this hypothesis.

Additionally, the X12 reduced 80% fluoride, 97.93% barium, 84.44% strontium, and 92.46% sulfate.

Despite lower reduction rates, these contaminants are at least present at levels below the HGL post-filtration, despite not being fully removed.

Additionally, only 10% of manganese was reduced, but it was only present in tiny trace amounts (0.00158 PPM), well below the HGL to begin with, and its potential health effects are linked to exposure to much higher concentrations. 

Aesthetic Contaminants

Score: 9.90

Our unfiltered water contained around 1 PPM of chlorine, which was detected by a chlorine test strip* that came in our sample-taking kit. 

After purifying the water in the Waterdrop X12, chlorine was no longer present at detectable levels, so the system got the perfect score in this category. 

*Chlorine is highly volatile and dissipates quickly, so we had to test it immediately ourselves after taking our water sample to ensure accurate results. 

Minerals & Salts

While the difference in minerals and salts concentrations doesn’t contribute to our scoring for Contaminant Reduction, it’s still an important consideration for any reverse osmosis system. 

RO systems purify water, which means they greatly reduce or remove all impurities, good and bad. 

The Waterdrop X-12 has a built-in remineralization filter, so we expected it to introduce trace concentrations of some of the healthy minerals removed by earlier filtration stages in the system.

Our test results showed that calcium was reduced by 74%, carbonate by 86%, magnesium by 83%, and sodium by 76%. 

Although this is a reduction overall, it’s not a complete elimination, so we think it’s likely that the unit’s remineralization filter is adding trace amounts of calcium, magnesium, carbonates, and sodium back to the filtered water. 

This is also evidenced by the alkaline pH of our purified water: the pH reading was 8. If we compare this to our test of the Waterdrop G3, without remineralization, where the purified water pH was 6.3, it’s apparent the X12 does indeed increase pH post-filtration.

Interestingly, in our X12 test, our unfiltered water was already alkaline at 8.5 pH, so the system technically lowered the pH. But the pH of the purified water is still higher than neutral and much higher than typical RO water, which is acidic due to its lack of minerals. 

Performance Certifications

Score: 8.00

Since our own testing is limited to the contaminants our water contains, we also look for official performance certifications from the NSF, WQA, or IAPMO for a water filter’s contaminant reduction performance. 

The NSF Waterdrop X Series is IAPMO Certified to NSF/ANSI Standard 58, for the reduction of TDS.  

However, the system didn’t get the best score in this category because it’s only certified for TDS reduction, which is just one of the 13 contaminants listed on the product page, or 7% of Waterdrop’s overall reduction claims.

We’d like to see Waterdrop obtaining certifications for the reduction of more specific contaminants with health effects, like lead, arsenic, and PFAS, in the future.

🚦Filtration Rate

Score: 10.00

The Waterdrop X12 has an excellent filtration rate of 1,200 GPD (gallons per day). 

In fact, the system’s purified water production rate is excessive and unnecessary for most average situations. On average, people use 70 gallons of water per day for everything (not just drinking). So 1,200 gallons+ per day for a system installed at your kitchen sink is overkill for most residential drinking water needs. 

Of course, there are a few specific use cases that may require large volumes of water purified per day. For instance, the X12 might be ideal for cafes or restaurants, rather than a residential application. 

However it’s good to note that the higher production rate also means a faster flow rate from the faucet. So if the speed at which you can fill your glass is important to you, this is worth considering.

🔁 Efficiency Ratio

Efficiency ratio, also known as pure to wastewater ratio or recovery rate, is the volume of water purified compared to water wasted during the RO process, expressed as a ratio. 

Since wastewater production is only an byproduct of reverse osmosis, we don’t currently assign scores for this testing category. 

However, it’s still important to acknowledge the efficiency of an RO system before you spend your money, since the volume of water waste will affect your water bill. 

Waterdrop is well known for its high-efficiency systems, and the Waterdrop X12 is no exception. It has a 3:1 drain ratio, meaning that for every 3 gallons of water purified, around 1 gallon of reject water is produced. 

To put this into perspective, conventional tank-based RO systems waste as much as 4 gallons of water for every 1 gallon purified, so the X12 is much more efficient.

📐 Design

Score: 9.70

The Waterdrop X12 has a simplistic design, with most of its components housed in a white rectangular box that sits underneath your kitchen sink. The unit measures 18.2 by 6.25 by 16.72 inches (L X W X H).

The X12 runs off electricity and comes with a waterproof power plug and cord. It also has a dedicated faucet that you’ll need to install separately at your sink. 

As a tankless RO system, the X12 filters water on demand, rather than storing purified water in a tank. That means it has a much smaller footprint than a system with a tank, so it’s a good choice for under-sink areas with limited space. 

Component Quality

Score: 9.50

The Waterdrop X Series wasn’t far off getting our top score for component quality. 

We noted that it feels sturdy and well-made, and the separate faucet is a nice touch, ensuring your purified water won’t get recontaminated by the metals in your existing faucet. 

The water comes into contact with plastic components, including tubing. These are made from Polypropylene (PP) and Polyethylene (PE) plastics, which are both BPA-free, food-safe, and FDA-approved for food contact. 

However, even BPA-free plastics may re-contaminate the water with other bisphenols or microplastics.

Smart Features

Like many Waterdrop products, the X12 has a few smart features that could be helpful for you.

It has a digital TDS monitor, which isn’t essential, but could be interesting if you appreciate being able to monitor the system’s TDS reduction.

We spoke to a Waterdrop rep about this feature, who confirmed that the TDS reading on the faucet is taken post-remineralization filter, so the TDS reading is likely to be a bit higher than the average for RO water (under 25 PPM) due to the presence of these trace minerals. 

The smart faucet also displays the filter life indicators, so you know in advance when to buy new filters, without having to rely on your own phone calendar reminders. 

Additionally, you can adjust the water volume from the faucet to meet your specific needs. Again, it’s not an essential feature, but a nice touch all the same. 

Certification

Score: 10.00

The presence (or lack) of a certification for materials safety or quality also impacts the overall design score that we award to water filters in this category. 

The systems in the Waterdrop X Series are all certified for materials safety as a component of their NSF/ANSI 58 performance certification obtained by IAPMO. They also have an IAPMO certification to NSF 372, for lead-free design, so it got the top score from us here.

Design Setbacks

While the X12 and other RO systems with a tankless design have the advantage of being space-saving, there’s one key setback of these systems to be aware of. 

Tankless RO systems are susceptible to TDS creep, which can temporarily increase the TDS in the purified water and reduce the water output, affecting the system’s performance efficiency. 

Filter Materials & Media

There are three filters in the Waterdrop X Series:

• Pre-sediment and activated carbon block filter: This removes sediment and particulates that could clog the RO membrane, as well as disinfection chemicals, their byproducts and other organic contaminants. 
• RO membrane: Most RO membranes are made from either cellulose acetate blends or polyamide composites.
• Polishing carbon/ remin filter: This final polishing filter stage targets any remaining VOCs, tastes, and odors, and is usually made from natural materials like coconut shells. It also has a remineralization media integrated.

⚙️ Setup

Score: 7.00

The Waterdrop X Series got quite a low setup score from us, and that’s because installing an under-sink RO system with a dedicated faucet takes more work due to the extra processes required. 

That said, we still found the installation process pretty straightforward, and Waterdrop’s instructions in the user manual were easy to follow. The entire process took about 2 hours.

Our sink already had a hole, so we didn’t have to drill one to install the separate faucet. That made our job easier. 

However, we did have to rewire the outlet under the sink, because the entire outlet was switched and used for the disposal.

Drilling the hole for the drain line was easy enough, and we used the connector for the drain tube as a guide. 

After being powered up for the first time, the system starts flushing automatically for 35 minutes (you can monitor its progress with the countdown timer on the smart faucet). After that, it’s ready to be used for drinking water.

We think you’ll be able to install this system yourself if you’re quite handy. If you’re not good with tools, see if you can get a friend or neighbor to help you.

🔧 Maintenance

Score: 10.00

Beyond setup, we found the Waterdrop X Series much easier to maintain, as reflected by its score in this category.  

Servicing Requirements

10.00

Replacing the filters is easy because we could use the filter change indicator display on our smart faucet. 

The filter replacement indicators change color to represent the filter’s remaining lifespan, and the system will beep while in use whenever a replacement filter is needed.  

There are three filters to replace, which could be a setback for you if you’d prefer to keep maintenance to an absolute minimum. But this is always going to be the case with a multi-stage system like an RO purifier. 

The actual process of removing the old filter and slotting the new filter in place is simple and straightforward.

Costs

Score: 10.00

In terms of ongoing spend, we calculated that the Waterdrop X12 would cost us 0.14/ gallon to maintain. This was based on the combined cost-per-gallon of the three filters in the system: 

Filter	Cost	Capacity (gal.)	Cost per Gallon
F1A	$32.99	1,100	$0.02
F2	$29.99	550	$0.05
F3	$159.99	2,200	$0.07

The X12 has a very low cost per gallon because its replacement filters are affordable and need replacing infrequently (every 6-24 months, depending on the filter). 

Interestingly, we’ve found that the systems we’ve tested with a higher upfront cost tend to be more affordable to maintain in the long run. So although you’re paying more upfront, your ongoing spend is less. 

🏢 Company

Score: 8.65

The models in the Waterdrop X Series are a serious investment, and we wanted to know how Waterdrop honors its customers with warranties, shipping, and returns policies. 

Warranty

Score: 8.50

The Waterdrop X Series systems are backed by an upgraded 2-year warranty (compared to their standard 1-year warranty on most other products) against defects against quality issues (not misuse) throughout this period.

Under the warranty, you’ll be able to return your system and get it repaired, swap out a component, or replace the entire system for free, depending on the issue reported. 

Shipping 

Score: 9.50

Waterdrop offers free Economy Shipping for customers in most US states, although the following regions are currently excluded: Alaska, American Samoa, Hawaii, Guam, Marshall Islands, Micronesia, Northern Mariana Islands, Palau, Puerto Rico, or the U.S. Virgin Islands.

You can choose to upgrade to Standard Shipping (which is free if you spend $200) or Express Shipping (which costs $12.99) to get your product shipped faster. 

View Waterdrop’s shipping policy here.

Returns

Score: 8.00

You can test the Waterdrop X series at no risk thanks to Waterdrop’s 30-day return policy. However, to be eligible to return your unit for a full refund within this period, you’ll need to disassemble it and return it in its original packaging, and the return shipping fee will come out of your own pocket. 

You can actually return your system to Waterdrop beyond the 30-day returns window, but you won’t get a full refund – there’s a 10% restocking fee on top of the return shipping fee.

Check out Waterdrop’s returns policy for more information.

💰 Value For Money

We want to finish this review with a word on overall value for money. 

RO systems are expensive, and that’s something you have to account for if you want to purify your water, as opposed to removing select contaminants with a water filter. However, the value for money should still be there.

While the Waterdrop X12’s ongoing cost of maintenance is low, we don’t feel that the upfront cost ($1,300) is worth it for the features you get. Even after extensively reviewing the system, we don’t think it offers anything uniquely special that justifies its high price. 

It appears that the higher cost is due to the integrated remineralization filter and the high daily production rate. The older G3 model offers better value for money, even though the remineralization filter has to be installed externally.

And if you are willing to consider a conventional system with a tank, you should definitely check out the Cloud RO.

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