These two Waterdrop systems look almost identical and do the same essential job — so the only real question is whether the G3P800 is worth £200 more than the G3P600. For most UK homes, our research says no. Here’s exactly where your extra money goes, and who should spend it.
The short answer
- Most UK households → G3P600 (£399.99). Same clean water, £200 cheaper.
- Large or high-demand homes → G3P800 (£599). Faster flow and better efficiency you’ll actually use.
The filtration quality is comparable. You’re paying for speed and water-efficiency, not cleaner water.
Head-to-head
| G3P600 | G3P800 (X8) | |
|---|---|---|
| UK price | £399.99 | £599 |
| Flow rate | 600 GPD | 800 GPD |
| Efficiency (pure:drain) | 2:1 | 3:1 |
| Filtration | 8-stage | 9-stage |
| NSF certifications | 42, 58, 372 | 58, 372 |
| Annual filter cost | ~£148 | ~£150 |
| Install | Under-sink + 13A socket | Under-sink + 13A socket |
| Best for | Most UK homes | High-demand households |
Where the £200 goes
Three differences, in order of how much they actually matter:
- Flow (600 vs 800 GPD). The G3P800 fills a glass a couple of seconds faster. Genuinely useful if your household runs the tap constantly; invisible to a typical couple or small family.
- Efficiency (2:1 vs 3:1). The G3P800 wastes about a third less water to drain. On a metered London supply that’s a small ongoing saving — but nowhere near enough to recoup £200 on its own.
- Certifications. Here the cheaper G3P600 actually edges ahead: it adds NSF/ANSI 42 (chlorine taste & odour) certification that the G3P800’s listings don’t always cite. Both reduce chlorine well in practice, but if “more certified” matters to you, it’s a point for the G3P600.
That’s the whole story. There’s no filtration-quality gap that justifies the price difference for most buyers.
UK hard-water angle
In hard-water London and the South East, the G3P800’s better efficiency is its most defensible advantage — wasting less water matters more when you’re metered. But both handle hardness identically at the tap (clearer kettles, no scum on tea), and both benefit from changing pre-filters toward the shorter end of their life in very hard water.
Verdict
For the vast majority of UK homes, buy the Waterdrop G3P600 and put the £200 toward filters or anything else — you get the same clean water and won’t notice the missing speed. Only choose the G3P800 if you have a large, high-demand household or you’re on a metered supply and value the better efficiency. When in doubt, the cheaper one is the right answer here.
See also our Best Reverse Osmosis Systems UK guide and the Waterdrop vs AquaTru comparison if you’re still weighing under-sink against countertop.
Frequently asked questions
Is the Waterdrop G3P800 worth £200 more than the G3P600?
For most UK homes, no. The G3P800 is faster (800 vs 600 GPD) and more water-efficient (3:1 vs 2:1), but filtration quality is comparable. The premium is only worth it for large or high-demand households, or metered supplies.
What's the actual difference between the G3P600 and G3P800?
Flow rate (600 vs 800 GPD), efficiency (2:1 vs 3:1 pure-to-drain) and stage count (8 vs 9). Interestingly the cheaper G3P600 also carries an extra NSF/ANSI 42 certification the G3P800 doesn't always cite.
Do the G3P600 and G3P800 remove the same contaminants?
Effectively yes — both are reverse osmosis systems that reduce TDS, PFAS, lead, chlorine and limescale-forming minerals. The difference is speed and efficiency, not what comes out of the tap.
Which is better for a big family?
The G3P800. Its 800 GPD flow and 3:1 efficiency suit households that use a lot of water and don't want to wait at the tap. Smaller households won't use that headroom and should save with the G3P600.