Waterdrop G3P800 Reverse Osmosis System - Tankless 800 GPD Fast Flow

Our review of the Waterdrop G3P800 finds it best suited for large households or anyone who needs continuous, high-volume purified water without a storage tank. The single biggest reason to buy is its combination of an 800 GPD capacity and a tankless design that delivers fast, consistent flow - the system filters a cup of water in about 5s and supplies steady water on demand. Installation requires drilling two holes, and the included smart faucet gives immediate feedback on water quality, making this a practical choice for kitchens where space and rapid flow matter.

Key Features

• Tankless 800 GPD capacity: Provides a very high daily output so large families get continuous purified water without waiting for a tank to refill.
• 3:1 pure to drain ratio: Uses advanced dispensing technology to reduce wastewater compared with many traditional RO systems, producing one cup of waste for every three cups of filtered water.
• 10-stage filtration: Tested by an independent lab to reduce PFAS, fluoride, heavy metals, salts and certain radioactive substances for broad contaminant removal.
• NSF/ANSI certifications: Certified to NSF/ANSI 42, 53, 58 and 372 standards for reduction of chlorine, TDS and lead-free materials, assuring verified performance and safer components.
• Smart faucet with LED: Built-in LED indicates water quality and has a very long rated lifespan, automatically illuminating when water flows for quick status checks.
• Space-saving design: The tankless under-sink layout frees up cabinet space and ensures fresh water production on demand.

Who It's For

This system is ideal for families, small businesses, or households on well water that need a continuous, high-volume supply of purified drinking water and want a tankless under-sink installation. The fast flow and 800 GPD capacity make it especially useful where several people may fill pitchers or run appliances simultaneously.

Buyers who prefer a simpler, no-drill countertop filter or who need a plug-and-play pitcher-style solution should look elsewhere, since the G3P800 requires drilling two installation holes and under-sink plumbing work. Those who want the smallest possible initial cost may also consider less powerful systems.

Pros & Cons

Pros

• Very high flow and capacity, delivering fast water and meeting the needs of large households.
• Comprehensive 10-stage filtration reduces a wide range of contaminants including PFAS and fluoride.
• Space-saving tankless design and a smart LED faucet make monitoring and installation neater under the sink.
• NSF/ANSI certifications back up claims for TDS, chlorine reduction and lead-free materials.

Cons

• Requires drilling two holes for faucet and drain connections, which adds installation steps compared with non-drill options.
• As a high-capacity RO system, it is larger and more complex than basic countertop filters and may be more than some households need.

Specifications

Product type	Tankless under-sink reverse osmosis system
Daily capacity	800 GPD
Pure to drain ratio	3:1
Filtration stages	10-stage filtration
Certifications	NSF/ANSI 42, 53, 58, 372 certified
Faucet	Smart LED purifier faucet with TDS display

Our Verdict

The Waterdrop G3P800 is a strong value for anyone who needs high-volume, reliable purified water and prefers a tankless, space-saving under-sink solution. Its fast flow, verified multi-stage filtration and smart faucet make it a practical upgrade over smaller RO units, though the drilling and installation effort mean it is best for those ready for a permanent under-sink installation.

Frequently Asked Questions

How many holes are needed to install this system?
Two holes are required: one for the RO faucet and one for the drain pipe connection.

Is the G3P800 certified for contaminant reduction?
Yes, it is certified to NSF/ANSI 42, 53 and 58 for reduction of chlorine, taste, odor and TDS, and NSF/ANSI 372 for lead-free materials.

Does the system use a storage tank?
No, it is a tankless design that delivers purified water on demand and saves under-sink space.