The most popular category for California homeowners. Tankless, multi-stage RO systems that install under your kitchen sink. NSF certified, smart monitoring, and professional installation available.
All prices are for the unit only. Installation available from $199.
Waterdrop's flagship undersink RO. The G3P800 delivers the fastest flow rate in the lineup, a smart LED faucet that shows real-time TDS levels, and built-in UV sterilization for an extra layer of protection. Perfect for large families and heavy water users.
The sweet spot of performance and price. The G3P600 offers 600 GPD flow with smart monitoring and the same multi-stage filtration as the flagship. Ideal for families of 3-5 who want premium filtration without the premium price.
Designed for smaller under-sink cabinets. The D6 packs 600 GPD performance into a compact footprint with full 7-stage filtration. Great for apartments and condos with limited cabinet space.
The reliable workhorse of the Waterdrop lineup. The G2P600 uses composite filter technology for consistent filtration performance. A proven design at an excellent price point.
The only undersink model with alkaline remineralization. The T4-A adds beneficial minerals (calcium, magnesium) back to your purified water for a natural, healthy taste. Dual flow output lets you choose purified or alkaline water.
The entry point to Waterdrop undersink RO. The G2 offers full 7-stage filtration with 400 GPD flow. Perfect for 1-2 person households or anyone who wants excellent filtration on a budget.
The most affordable Waterdrop undersink system without sacrificing quality. Twist-and-lock filter replacement takes 30 seconds. Great first RO system for budget-conscious buyers.
Side-by-side comparison to find the right fit
| Model | GPD | Stages | TDS Reduction | Tank | Smart Features | UV | Alkaline | Price |
|---|---|---|---|---|---|---|---|---|
| G3P800 | 800 | 7 | 99.9% | Tankless | Smart Faucet + TDS | Yes | No | $999 |
| G3P600 | 600 | 7 | 99.9% | Tankless | Smart Monitor | No | No | $539 |
| D6 | 600 | 7 | 99.9% | Tankless | Filter Indicator | No | No | $399 |
| G2P600 | 600 | 5 | 99% | Tankless | Filter Indicator | No | No | $359 |
| T4-A | — | 5+ | 99% | Tankless | Dual Flow | No | Yes | $329 |
| G2 | 400 | 7 | 99% | Tankless | Filter Indicator | No | No | $299 |
| T3-C | 450 | 5 | 99% | Tankless | Filter Indicator | No | No | $279 |
Quick guide based on your household needs
You need high flow rate to keep up with demand. The G3P800's 800 GPD means zero wait time even when multiple people are filling water bottles, cooking, and making coffee at the same time.
The G3P600 hits the sweet spot — 600 GPD is more than enough for a typical household, and the smart monitoring keeps you informed about filter life and water quality.
Limited under-sink space? The D6's compact design was built for this. Full 600 GPD performance in a smaller footprint. Ideal for condos and apartments.
You want clean water without spending $500+. The T3-C delivers NSF-certified RO filtration with twist-and-lock filters that make maintenance a breeze. Same clean water, smaller price tag.
Want purified water with healthy minerals added back? The T4-A is the only model with alkaline remineralization. Dual flow output lets you choose between pure RO and mineralized alkaline water.
If you want the best bang for your buck, the G3P600 offers premium features at a mid-range price. Smart monitoring, 600 GPD flow, 7-stage filtration — hard to beat.
Waterdrop RO systems remove 99.9% of over 1,000 harmful contaminants
The EWG found that California water systems serve water with contaminant levels exceeding health guidelines. PFAS, lead, and chromium-6 are widespread. Protect your family with a Waterdrop RO system that removes 99.9% of these contaminants.
Read Our California Water Quality GuideEvery undersink system can be paired with certified installation. Our technicians handle water line connection, faucet installation, drain routing, and system testing. Most installs completed in 1-2 hours.
Waterdrop undersink reverse osmosis systems have become the go-to choice for California homeowners who want clean, purified drinking water straight from the tap. Unlike basic pitcher filters or fridge filters that only reduce chlorine taste, Waterdrop RO systems use multi-stage filtration — including a semi-permeable RO membrane — to remove 99.9% of contaminants including lead, PFAS, fluoride, chromium-6, microplastics, and hundreds of other harmful substances.
Every Waterdrop undersink system features a tankless design, which means no bulky storage tank taking up your cabinet space. Water is filtered on demand and delivered fresh. The higher-end models like the G3P800 include a smart LED faucet that displays real-time TDS (Total Dissolved Solids) readings and filter life — so you always know exactly how clean your water is.
When you buy a Waterdrop system from us, you're buying from an authorized partner listed on Waterdrop's official installer directory. This means your manufacturer warranty is fully honored, you get genuine products (not counterfeit or refurbished units), and you have access to certified installation technicians who know these systems inside and out. Amazon sellers may offer slightly lower prices, but many are unauthorized — meaning your warranty could be void, and you're on your own for installation.
Choose your Waterdrop undersink RO system and book professional installation. Most installs completed same day.
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