The household job this tankless RO system handles
- Measure your faucet hole diameter before buying, since the smart faucet replaces the existing one and needs the right opening.
- Check that a grounded outlet sits within reach under the sink, because the system needs power to run.
- Confirm the cartridge replacement schedule and price so you know the ongoing cost beyond the purchase.
The Waterdrop G3P800 is a tankless reverse osmosis unit that mounts under the kitchen sink and filters water at the tap. Its 10-stage filtration is tested to reduce PFAS, fluoride, heavy metals such as lead and chromium, salts including nitrate and chloride, and radioactive substances like radium, according to the manufacturer. It holds NSF/ANSI 42, 53, 58 and 372 certifications covering chlorine, TDS and lead-free materials.
Output reaches 800 gallons per day, and the design sends one cup of wastewater out for every three cups of filtered water. That suits a large household drawing drinking water all day, and skipping the tank frees up cabinet room. The smart faucet reports TDS level and water quality as you pour.
We'd consider this a fit for a busy family that wants filtered water on demand without waiting on a tank to refill. Our advice is to measure your under-sink area first, since the unit and its tubing share that cabinet with your disposal and pipes.
What $759.00 buys and how the comparison works
The price is $759.00, which runs $64.17 under the typical price over the last 90 days of $823.17. That works out to about 8 percent less than the system's recent going rate.
Replacement filters are a separate, recurring cost, and this listing doesn't spell out their prices or how often each stage needs changing. Dig into that before you treat $759.00 as the whole bill.
| Offer detail | Recorded value |
|---|---|
| Amazon price | $759.00 |
| Customer rating | 4.5 |
| Customer reviews | 5235 |
| Typical price over 90 days | $823.17 |
| Difference | $64.17 (8 percent) |
The running cost question to settle first
This system passes water through 10 stages, including a reverse osmosis membrane and other cartridges. What isn't stated here is the replacement interval for each filter or what those cartridges cost.
Ask the seller for the filter schedule and current cartridge prices, since those numbers decide your real ongoing spend after the initial purchase. A drain connection and a nearby outlet are also worth confirming before installation day.
Who should skip a tankless RO system
If you rent and can't change the plumbing under your sink, a system that needs its own faucet and drain line is likely more than you want to take on. The same applies when a tiny cabinet can't hold the unit alongside its tubing.
A one- or two-person household that sips little drinking water may not need 800 gallons per day or a 3:1 pure-to-drain ratio. A smaller or countertop filter could be the simpler answer.
Before you commit, confirm the faucet hole size and that an outlet sits close enough to power the system.
Product details
| Model | WD-G3P800-W |
|---|---|
| Color | White |
| Size | 800 GPD |
