The Waterdrop G3P800 — sold in the UK under the “X8” name — is the top of Waterdrop’s tankless reverse-osmosis range. It’s faster and more water-efficient than the popular G3P600, but it costs around £200 more. The question almost every UK buyer is really asking is “do I actually need the extra power?” Based on our research, for most homes the honest answer is no — but for a specific group it’s the better buy.
Who is this for?
The G3P800 makes sense for large or high-demand households — think a busy family of five, a home that does a lot of cooking, or anyone who hates even a few seconds’ wait at the tap. Its 800 GPD flow and 3:1 efficiency mean more water, faster, with less sent down the drain.
For a typical UK couple or small family, that headroom mostly goes unused, and the cheaper G3P600 delivers the same filtration quality. So this is a “buy it if you’ll use it” product, not an automatic upgrade.
Key specs
| Waterdrop G3P800 (X8) | |
|---|---|
| Flow rate | 800 GPD — fastest in range |
| Filtration | 9-stage tankless RO |
| Efficiency | 3:1 pure-to-drain (better than G3P600) |
| RO membrane life | Up to 24 months |
| Warranty (UK) | 1 year |
| UK price | £599 |
What it removes
Filtration-wise the G3P800 does the same essential job as the G3P600 — it’s the speed and efficiency that differ, not what comes out of the tap. It’s certified to NSF/ANSI 58 (TDS reduction) and 372 (lead-free materials), and reduces:
- TDS / dissolved solids (NSF/ANSI 58 certified)
- PFAS “forever chemicals”
- Lead & heavy metals — relevant for older UK homes
- Chlorine, taste & odour
- Limescale-forming minerals
One note for the cautious: the G3P600 also carries NSF/ANSI 42 certification, which the G3P800’s listings don’t always cite. In practice both reduce chlorine well, but if maximum certified coverage matters to you, that’s a small point in the G3P600’s favour.
UK hard-water performance
In hard-water London and the South East, the G3P800’s higher efficiency is a genuine, if modest, advantage: a 3:1 pure-to-drain ratio wastes a third less water than the G3P600’s 2:1, which adds up over a year on a metered supply. UK owner reviews in hard-water areas echo the same limescale benefit as the G3P600 — clearer kettles, no scum on tea — with the added comment that the unit runs quietly, often described as “quieter than a dishwasher.”
As with any RO system in hard water, expect pre-filters to need changing toward the shorter end of their stated life.
Installation
Installation is essentially identical to the G3P600: cold-feed connection, drain into existing waste, and — importantly — it needs a 13A socket under the sink. Same UK caveats apply: measure your cabinet, and budget for an electrician if there’s no socket. Owners rate the process as approachable for a confident DIYer.
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Annual filter costs are broadly similar to the G3P600 — roughly £150/year — so running cost isn’t the deciding factor between the two. The G3P800’s better efficiency does trim your water bill slightly on a metered supply, but not enough to recover the £200 price difference on its own.
How it compares
| G3P600 | G3P800 (X8) | |
|---|---|---|
| UK price | £399.99 | £599 |
| Flow | 600 GPD | 800 GPD |
| Efficiency | 2:1 | 3:1 |
| NSF certs | 42, 58, 372 | 58, 372 |
| Best for | Most UK homes | High-demand households |
See the full breakdown in our G3P600 review and Best Reverse Osmosis Systems UK guide.
Verdict
The G3P800 earns 4.5/5 on its own merits — it’s the fastest, most efficient tankless RO system Waterdrop sells in the UK, and owner satisfaction is high (81% rate it 4★ or better). But a high score doesn’t make it the right buy for everyone. Buy it if you have a large or high-demand household and will actually use the extra flow, or you’re on a metered supply and value the better 3:1 efficiency. Save the £200 and get the G3P600 if you’re a typical UK household — you’ll get the same clean water and won’t miss the speed.
Frequently asked questions
What's the difference between the Waterdrop G3P800 and G3P600?
The G3P800 is faster (800 GPD vs 600) and more water-efficient (3:1 vs 2:1 pure-to-drain). Filtration quality is comparable. The G3P800 costs around £200 more, so it's worth it mainly for high-demand households.
Is the Waterdrop G3P800 the same as the X8?
Yes. 'X8' is the name Waterdrop uses for the G3P800 in the UK market. The specifications are the same.
Does the G3P800 waste less water?
Yes — its 3:1 pure-to-drain ratio sends roughly a third less water down the drain than the G3P600's 2:1, which is a small saving on a metered UK supply.
Is 800 GPD overkill for a UK home?
For most UK couples and small families, yes — the extra flow goes largely unused and the cheaper G3P600 delivers the same filtration. Large or busy households are the exception.
Does the Waterdrop G3P800 remove PFAS?
Yes. Like other reverse osmosis systems it reduces PFAS 'forever chemicals', along with TDS, lead and chlorine. It's certified to NSF/ANSI 58 for dissolved-solids reduction.