Waterdrop D6 Vs G3: The Brand’s Popular RO Systems Compared

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Waterdrop is well-known in the water treatment industry for its impressive range of modern, space-saving, forward-thinking countertop and under-sink reverse osmosis systems.

Two of Waterdrop’s most popular products are the Waterdrop D6 and the Waterdrop G3. In this guide, we’ve compared these water purification systems, discussing their features, pricing, benefits, and setbacks, to help you decide which (if any) is best for you.

πŸ“– TL;DR Waterdrop D6 vs G3: Which is Better?

The Waterdrop D6 and G3 both have their advantages and disadvantages, but one system might be better for you than the other, depending on your circumstances.

Based on our research, the Waterdrop D6 is better for folks who want to prioritize a fast flow rate and high efficiency, with minimal wastewater. The Waterdrop G3 is the better option for people who want a more comprehensive RO filtration process, with two additional filtration stages, and has the benefit of NSF 58 and 372 certification.

βš–οΈ Comparison Chart

Waterdrop D6Waterdrop G3
ProductWaterdrop D6Waterdrop G3
ProcessActivated Carbon + ROActivated Carbon + RO
Certifications or Testing–NSF 58, 372
Efficiency Ratio2:11:1
Stages of Filtration6 stages8 stages
Production Rate600 GPD400 GPD
Filter Life12 months6, 12, 24 months
Annual Cost~$100~$145
Warranty1 year1 year
Buying Options
Discounts $50 OFF at waterdropfilter.com
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$50 OFF at waterdropfilter.com
πŸ‘‰ Get coupon

πŸ’‘ Filter Comparison

Waterdrop D6

The Waterdrop D6 is a 600 GPD under-sink RO system that uses 6 stages of filtration to purify tap water:

  1. A PP cotton layer
  2. An activated carbon fiber layer
  3. A microfiltration membrane
  4. A reverse osmosis membrane layer
  5. A post-activated carbon block layer
  6. Non-woven fabric

The system comes with a smart designer faucet that tells you your water’s TDS reading after filtration. It’s tankless, so water flows straight through the system and out of your faucet when you switch it on (you can apparently fill a cup in 8 seconds).

There’s only a single filter in the Waterdrop D6, which combines all 6 filtration stages and needs to be replaced once a year. The filter uses an automatic flushing function to keep itself clean during periods of non-use.

Waterdrop G3

The Waterdrop G3 is a 400 GPD under-rink RO system that purifies tap water with 8 stages of filtration:

  1. A PP cotton layer
  2. An activated carbon block filter
  3. A scale inhibitor membrane
  4. A reverse osmosis membrane layer
  5. A post-activated carbon block layer
  6. A second PP cotton layer

We know: that’s only 6 stages of filtration. However, Waterdrop assures us that the G3 uses 8 stages of filtration, so we assume that two of the filtration layers have a double layer of the same filter media.

Like the D6, the G3 has a smart faucet that shows your outgoing water’s TDS, so you can check the system is working properly. It’s another tankless unit, this time with a slightly slower 400 GPD flow rate (versus the D6’s 600 GPD flow rate), and can apparently fill a glass of water in 12 seconds.

The G3 has three separate filters: a CB filter cartridge, an RO filter cartridge, and a CF filter cartridge. That means you need to replace three filters rather than just one per year. Like the D6, the G3 automatically flushes its filters for 20 seconds every 2 hours or after a blackout.

Waterdrop g3 CF filter change

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🧫 What Contaminants Do They Remove?

The Watdrop D6 can remove “most pollutants”, including chlorine, lead, nitrates, benzene, PFAS, chromium, and more. Waterdrop doesn’t give an estimated TDS reduction for this system, which is a shame, because it does tell us that (based on testing) the Waterdrop G3 has an average TDS reduction rate of 91.9%.

We assume that, like all traditional RO systems, the D6 and the G3 can greatly reduce TDS levels, remove harmful substances, and improve water quality. Since they use very similar water purification processes (the G3 just has a couple more treatment stages), the filters should both be capable of reducing the majority of drinking water impurities.

🚦 Performance Comparison

Waterdrop D6

The Waterdrop D6 has some unique performance, benefits, and a few setbacks, when compared to the G3.

The biggest performance benefit of the D6 is that it has a faster flow rate than the G3, so you can fill a glass of filtered water around 4 seconds faster.

Another performance benefit of the D6 is that its pure-to-wastewater ratio is better than the G3’s, so you’ll waste less water in the process of producing pure water. The system has a 2:1 efficiency ratio, meaning that only 1 gallon of water is wasted for every 2 gallons of water purified – much better than the 1:4 efficiency ratio of traditional reverse osmosis systems.

The D6 combines six thorough stages of reverse osmosis within a single filter cartridge, and you can rely on the unit to deliver quality pure water that’s free from virtually all TDS thanks to the system’s 0.0001-micron membrane pore size.

Handily, you can get an instant insight into the D6’s performance at any time because it comes with a smart faucet that shows a TDS reading of your filtered water. If the TDS level starts creeping up, it’s a sign that the filters or RO membrane may need replacing. Plus, the system maintains its performance by occasionally flushing the filters, removing trapped contaminants and extending the filter lifespans.

Onto the negatives: As far as we can tell, the D6 doesn’t have an NSF certification, so there’s no third-party proof to support the company’s performance claims. The system also doesn’t offer the same thorough filtration as the G3 because it has two fewer filter stages. However, it still has the all-important RO membrane layer for greatly reducing TDS.

Waterdrop d6 installed in home

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Waterdrop G3

The Waterdrop G3 has its own unique performance benefits and setbacks.

The G3’s biggest benefit is that filtration is split into three cartridges. While this means that you’ll need to spend more money on maintenance, it also means that each filter layer has more space – and a larger surface area – to trap contaminants, helping to remove as many impurities as possible from your water.

The G3 has an efficiency ratio of 1:1, meaning that 1 gallon of water is wasted for every 1 gallon of purified water produced. This is great compared to the traditional RO system’s 1:4 pure-to-waste water ratio, but it’s not quite as efficient as the D6’s 1:1 ratio.

As for flow rate, the G3 offers a respectable 400 gallons per day. Again, this is plenty fast enough for most people (you can fill a cup in about 12 seconds), but it still doesn’t quite match up to the D6’s 600 GPD flow rate.

You might be wondering why the G3 is around $100 more expensive than the D6 when a number of its performance features are slightly less impressive. The main reason is that the G3 has the all-important certification to NSF standards to support the manufacturer’s performance claims. We don’t have to simply assume that Waterdrop is reliably reporting that the G3 can reduce TDS because it’s IAPMO-certified to NSF/ANSI Standard 58, with a test data sheet to prove it. Reassuringly, the system is also certified to NSF Standard 372 for having ≀0.25% lead in its design materials.

See the performance of Waterdrop G3 from our third-party laboratory analysis below.

ContaminantMeasurementPre-InstallPost-Install% Change
Total Dissolved SolidsPPM8415-82.14%
Nitrate (as N)PPM1.10.1-90.91%

Like the D6, the G3 has a smart designer faucet that shows you how much TDS is in your purified water, so you get visual proof of the system’s performance and don’t have to guess when filter changes are needed.

To maintain its performance, the G3 also automatically flushes its filters to remove accumulated contaminants.

πŸ’² Models & Upfront Cost

Waterdrop D6 Models

The Waterdrop D6 is available in a single configuration, costing just under $400. Waterdrop suggests buying the system alongside the Remineralization Filter, which adds minerals back into purified RO water and can be used with all series Waterdrop RO water filters.

Waterdrop G3 Models

The Waterdrop G3 is also available in a single model configuration, costing around $500. Again, you can choose to add a Remineralization Filter to your purchase since remineralization isn’t a built-in filter stage for this system.

Waterdrop g3 RO filter

πŸ“† Filter Lifespan & Replacement Costs

Waterdrop D6

The Waterdrop D6 has a long filter life of 1,000 gallons, which equates to around 12 months. Handily, there’s only one filter in the unit that needs to be replaced, so you can spend less money per year on a single replacement filter.

You’ll only need to replace the filter when the faucet screen tells you to. The cost of a replacement filter (at the time of writing) is just over $100, meaning you’ll spend roughly $100 per year on maintenance for this system – not bad at all.

Waterdrop G3

The Waterdrop G3 has three filter cartridges, each with their own lifespans:

  • The CF filter has a 6-month lifespan
  • The CB filter lasts up to 1 year
  • The RO membrane has a filter life of 2 years

The cost of replacement filters for the G3 is higher because there are more filters to replace. The CF filter and CB filter cost around $30, while the RO membrane costs just under $100. So, based on filter lifespan, in your first year, the filter replacement cost will be around $90, and in your second, it’ll be $190. In the third, it’ll drop back down to $90 (because the RO membrane only needs replacing once every 2 years).

Again, the system’s smart faucet will give you real-time info about each filter cartridge’s remaining filter life and tell you when you need to buy a filter replacement.

πŸ’¬ Customer Reviews & Complaints

Waterdrop D6

We headed to Amazon to assess the customer feedback for all the water filters we review when possible, since we know that Amazon reviews are impartial and the manufacturer has less control over which reviews remain and which are deleted.

The Waterdrop D6 is highly rated (4.6 stars out of 5) by nearly 1,000 customers, who agree that the system has an attractive, space-saving design, is easy to install, and greatly improves water quality and reduces TDS.

Some customers complained that their filters didn’t last as long as expected (around 7 months versus Waterdrop’s projected 12 months), and some weren’t pleased with the frequency of flushing and how this increased their wastewater production.

Waterdrop d6 faucet extension drawing filtered water

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Waterdrop G3

The Waterdrop G3 is slightly more popular on Amazon, with more than 2,600 customer ratings. Interestingly, it currently has the same high star rating as the D6, telling us that, in terms of meeting or exceeding customer expectations, Waterdrop is doing something right with both products.

Customers say that the G3 is well designed and easy to install, and produces great-tasting water. A few reviewers also used Waterdrop’s customer service and were pleased with the support they received.

Some reviewers said that the system was noisier than expected, and some said the 400 GPD flow rate was a bit slow for filling larger containers (like a pitcher).

β˜‘οΈ Pros and Cons of Waterdrop D6 Vs G3

πŸ‘Waterdrop D6 – Pros

  • Faster flow rate of 600 GPD – The Waterdrop D6 has a faster flow rate of 600 GPD (versus the G3’s 400 GPD flow rate), so it’s the better choice for impatient folks who want to fill a glass or pitcher as quickly as possible.
  • Only 1 filter to replace – Another benefit of the D6 is that all the filter stages are combined in a single filter cartridge, so you only have one water filter to replace per year. That means you can keep maintenance costs low and put less effort into filter changes.
  • Better efficiency ratio – We’re also impressed with the D6’s 2:1 pure-to-wastewater ratio, which is slightly better than the G3’s 1:1 ratio. That means you can produce more purified water in this reverse osmosis system with less water waste per gallon.

πŸ‘Ž Waterdrop D6 – Cons

  • Fewer filter stages – The biggest setback of the D6 water filtration system compared to the G3 is that it has only 6 RO filter stages, while the G3 has 8. Don’t get it confused – 6 filter stages is still more than enough in a capable reverse osmosis system. But if you want your reverse osmosis water to be as pure as possible, the D6 isn’t the very best you can buy.
  • Not certified – Another disadvantage of the D6 is that, unlike the G3 RO system, it doesn’t have an official certification to support Waterdrop’s claims regarding its performance. That means we can only take Waterdrop’s word for it and hope it’s as capable as advertised.

πŸ‘Waterdrop G3 – Pros

  • Certified performance – The biggest reason to go for the Waterdrop G3 is that the system has an official IAPMO certification for its ability to reduce total dissolved solids, as well as a range of harmful contaminants that you’re probably keen to remove from your tap water. It’s also certified for a lead-free design.
  • More filtration stages – We also think you’ll love the G3 RO system if you’re looking for a filtration system with the most combined filter stages. The G3 combines 8 filter stages into one unit, giving you the highest-quality water treatment and pure, great-tasting water.
  • More thorough filtration process – Another advantage of the Waterdrop G3’s design is that the system uses three separate filter cartridges to treat water, which means water passes through a larger surface area in each filter stage, allowing for more contact with the filter media and more thorough contaminant removal.

πŸ‘Ž Waterdrop G3 – Cons

  • Flow rate & efficiency ratio are worse – It’s normal for a reverse osmosis system to have an effect on water pressure and flow somewhat, and the Waterdrop G3’s 400 GPD flow rate is the minimum required for a tankless RO unit. It’s slightly slower than the D6’s flow rate, too. The system’s 1:1 efficiency ratio is pretty great for a reverse osmosis system, but it’s also not quite matching up to the D6’s 2:1 ratio.
  • Costlier to buy and maintain – Another disadvantage of the G3 is that it’s around $100 more expensive upfront and up to $90 more expensive per year to maintain compared to the D6. This is largely due to the fact that the system is NSF certified and contains three separate water filters that need replacing on their own schedules. If your budget is on the smaller end, the G3 might be a stretch for you.
Waterdrop g3 smart faucet TDS reading

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❔ Should I buy the Waterdrop G3 or D6?

So, what’s the better investment: the Waterdrop D6 or G3?

Both of these Waterdrop under-sink water filter systems have a lot going for them. Waterdrop is known for its efficient, space-saving RO systems, and the G3 and D6 units tick a lot of our boxes. They’re both slim and space-saving thanks to their lack of a storage tank, they both have a decent water flow rate, and they both produce quality, great-tasting filtered water.

However, the right water filtration system for you depends on your priorities.

If your non-negotiable is that your RO water filtration system of choice needs to be NSF certified, and you’re happy to spend a bit more upfront and on maintenance, the G3 is the best reverse osmosis filter for you.

Alternatively, if you don’t mind if a system lacks an NSF certification as long as there are other ways to determine its performance (in this case, a TDS display on the faucet), and you’d rather spend a bit less on a system with a slightly faster water production rate and a slightly better efficiency ratio, go for the Waterdrop D3.

Waterdrop is a brand we’ve always had a great experience with, so whether you choose one of these Waterdrop RO systems or one of the brand’s other offerings, we’re pretty confident you’ll be happy with your decision.

  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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