Our Verdict
Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) — 8.7/10. A fast, space-saving tankless RO system that is worth it for households wanting high output, smart monitoring, and cleaner-tasting drinking water without a bulky storage tank.
Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800): 8.7/10
The Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) is a fast, space-saving under-sink RO system that makes the most sense for households that want high output, smart monitoring, and cleaner-tasting drinking water without a bulky storage tank.
Overview
In this Waterdrop G3P800 review, we’re looking at whether the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) is worth it as a premium tankless under-sink reverse osmosis system. It is designed to sit under a kitchen sink and deliver filtered water through a dedicated smart faucet. Its headline feature is the 800 gallons-per-day rated production capacity, which is much higher than many conventional under-sink RO systems and helps reduce the slow-flow feeling commonly associated with reverse osmosis.
This system is best suited to homeowners, renters with compatible plumbing access, families, coffee and tea drinkers, and anyone who wants a cleaner-tasting alternative to bottled water. It is also a strong fit for kitchens where cabinet space is limited, because the tankless design removes the need for a pressurized storage tank.
For comparison, see our iSpring RCC7AK buying guide if you are considering a more traditional tank-style RO setup, our Brita OB03 pitcher review if you only need a simple countertop option, or our Aquasana SimplySoft buying guide if your main concern is hardness and scale rather than drinking-water filtration.
The main trade-off is cost and installation complexity. The Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) is more advanced than a basic pitcher or simple carbon filter, and it requires an electrical outlet, a drain connection, and a dedicated faucet installation. For the right home, though, the combination of speed, filtration depth, and smart maintenance reminders makes it a compelling premium RO option.
Key features
The Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) is built for high-volume drinking water needs, with faster flow than many traditional RO systems.
The compact, tank-free body saves cabinet space and helps reduce the risk of stale water sitting in a storage tank.
The RO membrane targets dissolved solids and common contaminants that basic carbon filters are not designed to reduce as effectively.
The included faucet provides useful at-a-glance information such as filter status and water quality monitoring, depending on installation and usage conditions.
The system is designed to waste less water than older RO setups, with an advertised efficient drain ratio under suitable water pressure and temperature conditions.
Filter cartridges are designed for straightforward replacement, making ongoing maintenance easier than with many older cartridge housings.
| Feature | Value |
|---|---|
| Product name | Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) |
| System type | Tankless under-sink reverse osmosis filtration system |
| Rated production capacity | 800 gallons per day |
| Installation location | Under kitchen sink or compatible cabinet space |
| Water delivery | Dedicated filtered-water faucet |
| Filtration approach | Multi-stage filtration with reverse osmosis membrane and carbon filtration |
| Tank | No storage tank required |
| Smart monitoring | Faucet display for water quality and filter-life indicators |
| Drain connection | Required |
| Electrical outlet | Required |
| Filter replacement style | Twist-and-lock cartridge replacement |
| Best for | Households wanting high-flow RO water, reduced bottled-water use, and a compact under-sink setup |
| Not ideal for | Homes without under-sink power access, very low water pressure, or users wanting the cheapest possible filtration option |
Pros & cons
Pros
- Very strong 800 GPD rated capacity for an under-sink RO system
- Tankless design saves cabinet space
- Fast dispensing compared with many traditional RO systems
- Smart faucet makes filter status easier to track
- Cleaner taste than typical unfiltered tap water
- More efficient water use than many older reverse osmosis systems
- Filter changes are relatively simple
Cons
- Higher upfront price than basic under-sink filters
- Requires an electrical outlet under the sink
- Installation is more involved than a pitcher or faucet-mounted filter
- Still produces wastewater, as all RO systems do
- Replacement filters add ongoing ownership cost
- May require drilling if your sink or countertop lacks an available faucet hole
Performance
In everyday use, the biggest advantage of the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) is speed. Traditional reverse osmosis systems can feel slow, especially when filling a kettle, water bottle, or cooking pot. The 800 GPD rating gives this system a much more convenient flow rate, making it better suited to busy kitchens and families that use filtered water throughout the day.
Taste is another major strength. Reverse osmosis filtration is especially useful for reducing dissolved solids that can contribute to mineral-heavy, metallic, chlorine-like, or generally unpleasant tap-water flavor. For coffee, tea, ice, and plain drinking water, the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) should provide a noticeable upgrade over untreated tap water in many homes.
The smart faucet is genuinely useful because it removes some of the guesswork from maintenance. Instead of relying only on calendar reminders, the system gives visible feedback about filter life and water quality. That matters because neglected filters can reduce performance and flow over time.
Noise is generally limited to the sound of the internal pump and water movement while dispensing or flushing. It is not silent, but it should not be disruptive in normal kitchen use. The tankless design also means the system does not store a large volume of water under pressure, which helps keep the setup compact and modern.
Performance depends on your incoming water pressure, temperature, source-water quality, filter age, and installation quality. If your water pressure is unusually low or your plumbing layout is tight, installation may take longer or require additional parts.
Value for money
The Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) is not the budget pick in the under-sink filtration category. Its value comes from convenience, capacity, and a cleaner installation rather than the lowest initial price. If you only need basic chlorine taste reduction, a simple carbon under-sink filter will cost less and be easier to install.
If you want to compare lower-cost RO alternatives, consider the iSpring 6-Stage Under-Sink Reverse Osmosis System with Alkaline Remineralization or the Express Water 10-Stage Alkaline Reverse Osmosis Under-Sink Water Filter System.
However, if you specifically want reverse osmosis filtration and high daily output, the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) becomes much easier to justify. The tankless format saves space, the fast flow makes the system feel practical for daily family use, and the smart faucet helps reduce the chance of forgetting filter replacements.
It is also worth considering the long-term comparison with bottled water. For households that regularly buy cases of bottled water, a high-capacity RO system can reduce plastic waste, storage clutter, and recurring bottled-water purchases. You will still need to budget for replacement filters, but the convenience of having filtered water on demand is a major part of the value.
Final verdict
The Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) earns an 8.7/10. It is a strong premium under-sink RO system for households that want fast filtered water, a compact tankless footprint, smart monitoring, and better-tasting drinking water.
It is most worth it if you have the cabinet space, electrical access, and budget for a higher-end installation. It is less compelling if you only need a basic taste-and-odor filter or want the cheapest possible water filtration setup. For buyers who specifically want a modern high-output reverse osmosis system, the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) is a very competitive choice.
Is the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) worth it?
Yes, it is worth it for households that want high-flow reverse osmosis water, a tankless under-sink design, and smart filter monitoring. It is less worth it if you only need a low-cost carbon filter for basic taste improvement.
Does the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) need electricity?
Yes. The Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) requires an electrical outlet under the sink, which is one of the key installation requirements to check before buying.
Does the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) waste water?
Yes. Like all reverse osmosis systems, it sends some water to the drain during filtration. However, it is designed to be more efficient than many older RO systems, especially when installed under suitable water pressure and operating conditions.
Can I install the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800) myself?
Many DIY-friendly users can install it themselves if they are comfortable connecting water lines, installing a drain saddle, mounting a faucet, and working under the sink. If your countertop needs drilling or your plumbing layout is unusual, professional installation may be the better option.
Who should buy the Waterdrop Tankless Under-Sink Reverse Osmosis System 800 GPD (G3P800)?
It is best for families, frequent water drinkers, coffee and tea enthusiasts, and anyone who wants a compact, high-capacity RO system with smart maintenance reminders. It is not the best fit for buyers who lack an under-sink outlet or want the lowest-cost filtration solution.
