Waterdrop G3 Reverse Osmosis Review (Our Hands-on Testing)

We installed and tested the Waterdrop G3 in our home to see how it performed with everyday use. In our testing, we evaluated the system’s ability to remove contaminants from our water supply, the speed of water purification, the wastewater versus pure water production, and more. We compiled these talking points in this review, and at the end, we’ve ultimately shared whether or not we recommend this under-sink RO water filtration system.

Our Rating: 4.5/5

★★★★★

How We Review

The Waterdrop G3 is a compact, excellently designed reverse osmosis water filter, available in two configurations: G3P600 and G3P800.

Price: $539 – $999

Efficiency Ratio: 3:1

Stages of Filtration: 7

Production Rate: 800 GPD

Certifications or Testing: NSF 58, 372

Annual Cost: ~$145

Discount: Get $199 off – Click Here for Code

View price for G3P600

View price for G3P800

🧾 Overview of the Waterdrop G3 Reverse Osmosis System

The Waterdrop G3 is a tankless RO system designed to be installed underneath a kitchen sink. The unit has been performance certified by the NSF to Standard 58 for its ability to reduce TDS and chromium-6 in water.

There are two unit configurations in the G3 range:

• The G3P600, with a 600 gallon-per-day (GPD) flow rate
• The G3P800, with an 800 GPD flow rate

These systems use the same filter stages and the only difference is their water production rate: the G3P800 is the faster model. We’ll be discussing both of these systems in this review, but with a main focus on the G3P800, since this was the system that we installed and tested ourselves.

As a tankless unit, the G3 Reverse Osmosis System has a slim, space-saving design and houses three filters stacked on top of one another. The system uses water pressure and an internal pump to power water through the filter stages, including a semi-permeable RO membrane, removing thousands of trace contaminants.

Unlike some of the under-sink RO systems we’ve used, the Waterdrop G3 produces water on demand rather than storing it in a tank in advance. That means we had to wait for water to filter when we turned on our faucet, instead of simply accessing the purified water from the tank.

Price	$539 – $999
Efficiency Ratio	3:1
Stages of Filtration	7
Production Rate	800 GPD
Certifications/Testing	NSF 58, 372
Annual Cost	~$145

In our testing, the Waterdrop G3P800 reduced 82% of our water’s TDS. It did an excellent job at removing specific contaminants, including lead, fluoride, copper, arsenic, and chloride, which were completely eliminated. It also reduced barium, strontium, sodium, and more. As expected from an RO system, the G3P800 reduced healthy minerals in our water and decreased its pH. There’s no built-in remineralization filter with this system, although you can buy one separately from Waterdrop.

💡 First Impressions

Out of the box, the Waterdrop G3 is one of the more modern, tech-focused under-sink RO systems we’ve tested. When we got the G3P800 to review, it was priced at just under $1,000, but there was an on-site discount that brought the price down to $760. We’ve noticed that Waterdrop regularly offers deals like this, but they’re not applied automatically at the checkout, so make sure to enter the discount code if you see one on the product listing. If you’re unable to find a deal, the $1,000 price tag is undeniably expensive. Do we think it’s worth the cost? Personally, yes, given that the unit is more efficient and has a better purified water production rate than any other tankless RO system we’ve reviewed. We’ve discussed these features in more detail later.

Out of the box, our unit came with:

• The system housing and three initial filters
• A smart RO faucet
• A UV sterilizer
• A feed water adapter
• Three sets of flexible tubing
• A power adapter
• Drain saddle
• Five lock clips
• Teflon tape

As far as design is concerned, we were pleased with the features of this under-sink RO system. Waterdrop is known for its smart systems, and the G3P800 has a few useful features that made it easier for us to use the unit as intended. There are TDS meters on the smart faucet and the unit body, which we could use to check on the performance of the filters, and a filter life tracker, so we didn’t have to make our own calendar reminders for filter changes. Another unique perk of the unit is that it comes with a UV purifier (which boasts a 99.9% sterilization rate), so we had the reassurance of protection against pathogens. The only thing we felt it was missing was a built-in remineralization filter – we could buy one from Waterdrop, but it needs to be installed separately and costs an extra $30.

As we mentioned, there are three separate filter cartridges in the G3 unit. We estimated that we’d spend around $155 annually on filter replacements, which, given the upfront cost of the unit, we didn’t think was too bad.

To summarize our first impressions, the G30800 ticked most of our boxes in an under-sink RO system, and exceeded our expectations in some areas with a few unique features. It might be expensive, but it’s packed full of features that we found to be genuinely useful in helping to monitor and maintain the system’s performance.

🧪 Our Performance Test

We wanted to test the Waterdrop G3P800 in our own home to see what it could remove from our drinking water supply. Reverse osmosis systems can typically purify water, removing more contaminants than a standard filter, thanks to their semi-permeable membranes. So, going into testing for the G3P800, our standards were high – we expected to see a significant reduction in the contaminants detected in our feed water.

We tested our water with Tap Score, which involved taking before-and-after samples of our water supply and mailing them to Tap Score’s lab for professional testing. The company has a strict sample-taking protocol, which we followed closely to ensure that our results were accurate.

Tap Score delivered our results via an email link within just under a week. We had access to a dedicated online report for both our before and after water tests, which told us a few things:

• The quality of our water overall, with an assigned Tap Score from 1-99
• The contaminants detected in our water samples
• Whether these contaminants were linked to health, aesthetic, or plumbing effects

In the table below, we’ve shared the contaminants detected in our feed water versus those detected in our filtered water from the Waterdrop G3P800.

Contaminants With Health Effects

Our unfiltered water contained trace levels of 12 contaminants with possible health effects: arsenic, fluoride, lead, strontium, barium, zinc, nitrate, sodium, copper, manganese, selenium, and sodium. Of these contaminants, we were the most concerned about arsenic and lead, since these were present at levels that exceeded the HGL.

Some of the possible health effects associated with these contaminants include:

• Developmental outcomes
• Skeletal health issues
• Blood and nervous system effects
• Cardiovascular health problems
• Effects on kidney and liver health
• Immune effects
• Carcinogenic (cancer-causing) effects
• Effects on the eyes and vision
• Gastrointestinal issues
• Reproductive outcomes
• Respiratory problems

In our purified water sample, 9 out of these 12 contaminants weren’t detected at all, meaning that the Waterdrop G3P800 had effectively eliminated 100% of them from our water. Only barium, nitrate, and sodium remained in tiny trace amounts (0.0033, 0.1, and 1.65 PPM respectively) – well within the HGL.

TDS, pH, Minerals, & Salts

One of the setbacks of any system that uses a reverse osmosis membrane is that it reduces the good stuff as well as the bad stuff. The G3P800 was no exception in our testing, removing healthy minerals and affecting our water’s pH.

Our unfiltered feed water contained 84 PPM of total dissolved solids. TDS is a measure of all dissolved solids in the water, including healthy minerals and salts (our feed water contained 20.2 PPM of calcium and 2.13 of magnesium, for instance). Our initial water pH was 7.3, just higher than neutral.

Post-filtration, our water’s TDS had been reduced by 82%, down to 15 PPM. Our water’s minerals were both reduced by 87%, and its pH reading dropped to 6.3. This might seem alarming, but it’s normal for an RO system. We tested the G3P800 without a remineralization filter, and it’s likely that our water’s pH wouldn’t have dropped – and might have even increased – if we’d remineralized it post-RO treatment.

🚦 Performance

Aside from contaminant removal, we also wanted to test the Waterdrop G3P800’s abilities across several other performance categories, including purification speed and efficiency ratio. We also taste-tested our water to see whether the RO purification made a difference that we could notice.

Efficiency Ratio

Performance efficiency is one of the areas in which the Waterdrop G3P800 excels. We’ve tested dozens of under-sink tankless reverse osmosis systems, and this Waterdrop has one of the best efficiency ratios we’ve seen for a system of its kind.

The unit has a 3:1 pure-to-wastewater ratio, meaning that only 1 gallon of water is lost for every 3 gallons purified. In case you didn’t know, wastewater production is an unfortunate (and unavoidable) side effect of the reverse osmosis process, but most RO systems we’ve tested (even the modern ones) waste at least 1 gallon of water per gallon purified. We’ve only tested a few countertop RO systems that have 4:1 or 5:1 efficiency ratios, but none that offer on-demand under-sink filtration like the G3.

Overall Water Quality And Taste

We taste-tested our purified water and compared it to the taste of our unfiltered tap water.

While the G3 RO system had removed or greatly reduced all the harmful contaminants in our water, we hadn’t had issues with chlorine in our feed water anyway. So we didn’t notice an improvement in taste in this respect, but if your water is chlorinated, this system should near-enough eliminate chlorine and its associated tastes and odors.

Due to the pH reduction and the loss of minerals in our water, we thought it tasted a bit plainer and “flat” compared to our unfiltered tap water. We’re keen to taste-test our water again after installing Waterdrop’s post-remineralization filter to see how it improves our water taste by reintroducing healthy minerals like calcium and magnesium.

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Rate of Water Purification

Unlike standard water filters, RO systems are measured in GPD (gallons per day) rather than GPM (gallons per minute) for flow rate. This makes it slightly more difficult to imagine the speed of water flow, but something to note is that under-sink RO filters have a slower flow rate generally because they need to send water through multiple filtration stages, including the reverse osmosis membrane.

As a reminder, we got the Waterdrop G3P800 under-sink reverse osmosis system, which has a water production rate of 800 gallons per day. The other option is the Waterdrop G3P600, which has a slightly lower capacity of 600 gallons per day.

We’ve tested a few tankless reverse osmosis filters, and an issue that we sometimes experienced was a long wait time for our filtered water. While tankless systems are space-saving, they have to filter water on demand, rather than storing a batch of purified water in a tank, ready to be sent straight to the faucet. The G3P800 stood out to us in our research because its 800 GPD water production rate is the fastest we’ve ever seen.

How fast are we talking? Waterdrop says you can fill a glass in under 6 seconds, and with a new set of filters, we were getting similar results – our average filling time was between 6.2 and 7.5 seconds. We’d expect the rate of water production to decrease over time as the filters became more clogged with contaminants.  

📝 Filter Testing & Certifications

The Waterdrop G3 combines three filter cartridges: a carbon block and sediment pre-filter (CF), an activated carbon coconut filter (CB), and a semi-permeable RO membrane (RO). These have been certified to NSF Standard 53, for their ability to reduce TDS and chromium-6. The unit also has an NSF 372 certification for a lead-free design.

We always try to look for reverse osmosis systems with official certifications where we can because we like the reassurance of knowing a filtration system has been tested and approved by an organization we can trust. We were happy with the G3’s certifications, although we would have liked to see it tested to remove more contaminants under NSF 58.

🔧Installation & Maintenance Considerations

We found that installing the Waterdrop G3P800 was much easier than installing a traditional under-sink RO system, and the unit took up less space (it measures just 5.67 inches across).  

We installed the unit at our cold water pipe using the provided flexible tubing. Everything we needed for installing and setting up the system was included in our box, and the user manual has a detailed 8-step installation process, with diagrams included, that we found easy enough to follow.

There’s a bit of extra work required to drill a hole in your countertop for the RO faucet, which you’ll have to do if you don’t already have a hole (such as for a soap dispenser). We don’t recommend simply replacing your existing faucet with the RO faucet because the system can only be used with cold water, so you still need an additional faucet for hot water. We also had to connect the drain pipe to our drainage system, since we needed to be able to direct the wastewater somewhere.

In all, installing the system took us around 1 hour 30 minutes from start to finish. Do we think the install is possible if you’re not confident with DIY? Yes, but make sure to follow the instructions in the user manual carefully.

Installation aside, our only regular maintenance task was to change the filters according to our filter replacement schedule. The first set of filters was included with our initial purchase, but it was our job to buy replacement filters as and when we needed them.

Here’s the key maintenance information to be aware of:

• The CF filter needs changing every 6 months
• The CB filter lasts for 8-12 months
• The RO membrane lasts for two years
• The UV lamp doesn’t need changing at all – itlasts up to 50 years with little or no maintenance required

We didn’t have to remember to replace our filters thanks to the unit’s filter change reminder, which let us know when it was time to purchase replacements. Of course, this is just an indication based on a timer, and we knew that our exact filter life might vary depending on our water use and quality.

Changing the filters was quick and easy, and we didn’t have to shut off our water or power supply. We just had to twist out the old filter, insert the new filter in its place, and reset the filter life timer. Our only annoyance was having to flush the filters after changing them – the CF filter flushes automatically, but we had to manually turn on the RO faucet to flush the CB filter for 15 minutes, and the RO filter for 30 minutes, which was time-consuming and felt wasteful.

🤔 Should You Buy The Waterdrop G3 Reverse Osmosis System?

We recommend the Waterdrop G3 Reverse Osmosis System if you can stretch your budget to a smart, space-saving tankless under-sink RO unit that gives you reliable access to filtered water and is faster and more efficient than similar models.

However, the unit might not be right if you just want to produce filtered water and don’t want the setbacks of reverse osmosis, like water waste and healthy minerals reduction, or you want a filter that’s easy to install. In this case, you’re best looking at other systems that don’t use the RO process.

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