After 6 months of real testing in a UK hard-water home, this is my top recommendation.
If you’re comparing different reverse osmosis technologies, I’ve put together a complete Reverse Osmosis Systems UK guide covering countertop, under-sink and instant hot-water systems.
Looking at different filtration technologies? Our Water Filters UK guide compares reverse osmosis systems, under-sink filters, countertop filters, whole-house filtration and water softeners used in UK homes.
⭐ Quick Verdict – Is It Worth It?
Yes. After six months of daily use, the G5P700A remains my preferred compact under-sink RO system because it combines 700 GPD flow, a tankless design and built-in remineralisation in a relatively narrow unit.
- ✔ Fast 700 GPD flow rate
- ✔ Excellent contaminant removal
- ✔ Low waste ratio
- ✔ Compact & quiet
Less suitable for: Anyone wanting the cheapest possible RO system or whole-house limescale treatment.
| Model | Flow Rate | Best For |
|---|---|---|
| G5P700A | High | Large households |
| G3P600 | Medium | Most homes |
| X12 | Very High | High usage homes |
If you’re considering the Waterdrop G5P700A in the UK, the main question is simple:
👉 Is the Waterdrop G5P700A actually worth buying in the UK? After using it in my own kitchen for six months, I tested its TDS, flow, noise, taste, installation and everyday usability.
This Waterdrop G5P700A review UK involves testing it over several months (including TDS readings, flow rate, and filter lifespan), here’s what I found — and whether it’s the right choice for your home. If you want the best overall RO system for UK homes right now, the G5P700A is my top recommendation
The G5P700A is also featured in our guides to the best under-sink reverse osmosis systems in the UK and our full Waterdrop vs Osmio comparison, where we compare tankless and countertop RO systems side-by-side.
With PFAS now under UK government review in 2026, reverse osmosis systems like this are becoming increasingly popular for drinking water. See the PFAS UK water guide.
Why I Chose the Waterdrop G5P700A
I installed the G5P700A in my own UK kitchen and have used it daily for six months. I wanted a tankless reverse osmosis system that would fit comfortably beneath the sink while still providing fast flow and remineralised drinking water.
I had also considered the Waterdrop G3P600, but cupboard space was a major factor. The narrower G5P700A fitted my installation better, and its built-in remineralisation was particularly appealing because I prefer the taste to very low-mineral RO water.
In this review I cover my own installation, TDS readings, dispensing performance, noise, taste, filter costs and the differences I noticed compared with other Waterdrop systems.
Waterdrop G5P700A vs G3P600 — Which Should You Choose?
This review covers real TDS readings, installation notes, noise levels, filter costs, and you may be comparing it to the larger Waterdrop G3P600. If you’re deciding between these two models, here’s a quick breakdown. Both the Waterdrop G5P700A and G3P600 are excellent tankless reverse osmosis systems for UK homes, but they suit slightly different buyers.
The biggest difference is that the G5P700A includes an alkaline remineralisation stage, which adds calcium and magnesium back into the water after filtration. The G3P600 focuses on ultra-pure, low-TDS water without remineralisation.
The G5P700A also offers a slightly higher flow rate (700 GPD vs 600 GPD), making it better suited for larger households or heavy daily water use. However, the G3P600 is slightly more compact and usually costs less upfront, making it easier to install in smaller UK sink cupboards.
| Feature | G5P700A | G3P600 |
|---|---|---|
| Flow | 700 GPD | 600 GPD |
| Pure-to-drain ratio | 2:1 | 2:1 |
| Remineralisation | Built in | No built-in mineral stage |
| Design | Tankless | Tankless |
| Smart faucet | Yes | Yes |
| Dimensions | 42.4 × 14.5 × 35.3 cm | 46 × 14.4 × 45 cm |
| Best for | Compact cupboards + remineralised RO | Larger system + standard RO |
👉 Recommendation: My preference is the G5P700A if cupboard space and remineralisation matter most. The G3P600 is a strong alternative if you want a slightly larger conventional tankless RO system and don’t need built-in remineralisation.
If you want to compare more installed RO systems, see our guide to the best under-sink reverse osmosis systems in the UK. If you’re comparing models, the full G3P600 vs G5P700A guide explains the differences in efficiency and TDS reduction.
👉 Best Value Alternative
Want something cheaper but still powerful? The Waterdrop G2P600 is a great option.
Installation & Setup
Installation took less than an hour with a standard UK plumbing kit. The colour-coded tubing made it straightforward, and the digital faucet display synced immediately after the first flush. I didn’t need a separate booster pump because the G5P700A’s internal pump keeps a steady pressure even with our lower mains flow.
If you’ve installed a regular under-sink filter before, this will feel familiar — just with an extra drain line for the waste water.
Faucet hole size
This is another very practical detail.
For my quartz worktop, I needed a 25mm diamond hole saw for the RO faucet hole to install the G5P700A faucet.
That’s slightly larger than the 22mm many people associate with standard tap-style installations.
If you’re fitting this into quartz, composite or stone, double-check the required faucet hole size before installation. I used one like this.
First Impressions & Water Quality
Straight away, the taste difference was obvious. Tea and coffee tasted cleaner and smoother, with no chlorine aftertaste. Using a TDS meter, my tap water dropped from ≈ 300 ppm to around 15 ppm after filtration — a huge improvement for a hard-water area.
Compared with a simple carbon filter, this reverse-osmosis unit delivers noticeably clearer water and far less limescale on the kettle element.
The G5P700A also removes up to 99% of fluoride, which is a big priority for my family.
Performance After 6 Months
Six months in, performance is still consistent. Flow rate stays strong (about 1.8 L/min), and the system automatically tracks cartridge life through the LED indicators. Noise is minimal — just a short pump hum when dispensing.
Overall, the Waterdrop G5P700A review UK tests show consistent pressure and excellent mineral balance for daily use.
From my Waterdrop G5P700A review UK tests, the TDS levels stayed low even after six months.
Because the G5P700A is tankless, it does not use the separate storage tank found on traditional RO systems, reducing the amount of purified water held in storage before dispensing.
On my newer August 2026 test, incoming water measured 416 ppm and the G5P700A produced 22 ppm, showing that readings naturally vary with the incoming supply and remineralisation stage.
Waterdrop specifies a 2:1 pure-to-drain ratio, meaning roughly two parts purified water for every one part sent to drain. I haven’t independently measured the wastewater ratio, so I’m treating this as the manufacturer specification rather than my own test result.
Flow Rate
In my latest dispensing test, the G5P700A filled approximately 250 ml in 5.18 seconds, equivalent to around 2.90 L/min. This was a real household test rather than a laboratory flow-rate measurement, so mains pressure and installation conditions can affect results.
G5P700A Retest: TDS, Flow and Noise
I retested the G5P700A in August 2026 alongside the Waterdrop K19 countertop RO system using the same household water supply.
Test G5P700A K19 TDS 22 ppm 31 ppm 250 ml dispensing time 5.18 sec 23.62 sec Calculated flow ~2.90 L/min ~0.64 L/min Sound meter average* ~62 dB ~47 dB *Noise was measured at the same distance using a smartphone sound-meter app, so the figures are useful for comparison rather than laboratory-grade measurements.
The biggest difference was dispensing speed: in this test the G5P700A was about 4.6× faster than the K19. The K19 was quieter, while the G5 produced a more noticeable pump sound during operation.
Taste was subjective, but I preferred the G5P700A. Its water tasted slightly crisper, while the K19 tasted clean but flatter. The G5P700A includes alkaline remineralisation after RO filtration, which may contribute to that difference.
Waterdrop confirms that the G5P700A includes an alkaline mineral stage as part of its filtration system.
See my full Waterdrop K19 review for the countertop-system test.
How the G5P700A Handled My Warwickshire Limescale
Warwickshire is known for very hard water, and limescale has always been a constant issue in my home — especially in the kettle. After installing the Waterdrop G5P700A, the change in drinking water quality was immediate. Because it uses reverse osmosis, it removes the dissolved minerals that cause limescale, meaning the filtered water is essentially scale-free. Within days, there was no residue left in the kettle, and drinks like tea and coffee tasted noticeably smoother. It doesn’t replace a full-home water softener, but for anyone dealing with hard water in the UK, it’s a huge upgrade for drinking and cooking.
👉Check latest UK priceRemineralisation & Taste Balance
This is where the G5P700A beats most compact systems. The post-filter adds calcium and magnesium back into the purified water, bringing the pH closer to 7.5 – 8.0.
That small mineral lift keeps the water tasting natural — not flat like some RO systems — and helps protect copper plumbing from overly soft water.
If limescale is a problem throughout your home, not just in drinking water, an under-sink RO system like the G5P700A works best when combined with whole-home treatment. Many UK homes use a whole house water filter and softener combo to reduce limescale at the point of entry, then rely on RO for kettle- and coffee-machine water. We cover the best options in our guide to the best whole house water filter and softener combo UK.
Maintenance & Filter Costs
Filter replacement is genuinely tool-free: twist-out cartridges that take 10 seconds each. The system reminds you automatically when each stage hits 100 %.
Typical annual replacement cost: roughly £60 – £80 for all three cartridges.
Given the water quality improvement, that’s very reasonable. I keep one spare set in the cupboard to avoid waiting on delivery. Please see the guide for compatible replacement Waterdrop cartridge filters in the UK.
Does the G5P700A remove PFAS?
With the UK Government launching its PFAS Action Plan in February 2026, many homeowners are rightly concerned about “forever chemicals” in our tap water. Standard jug filters often struggle here, but the Waterdrop G5P700A is a different beast.
The Technical Proof
The G5P700A utilizes a 0.0001μm (micron) Reverse Osmosis membrane. To put that in perspective, a PFAS molecule is typically much larger than the tiny pores in this membrane.
The system has been independently tested by SGS to effectively reduce PFOA and PFOS (the two most common and high-risk PFAS compounds).
While no filter can claim 100% removal in every scenario, the G5P700A is designed to reduce detectable PFAS levels by up to 99%, bringing them well below the proposed UK statutory limits.
NSF/ANSI 58 Certified: This is the “gold standard” certification for Reverse Osmosis. It confirms that the system is structurally sound and capable of reducing the specific contaminants it claims to, including heavy metals and organic chemicals like PFAS.
Why this matters for UK Homes in 2026
As of early 2026, UK water companies are under increased pressure to monitor PFAS, but infrastructure upgrades take years. By installing a G5P700A, you aren’t waiting for the government to fix the pipes; you are creating a final barrier at your kitchen tap that provides immediate protection for your family.
Compared to typical Brita-style jug filters, which focus on taste and only partially reduce PFAS, the G5P700A’s reverse osmosis system removes contaminants at a much deeper, molecular level.
Pros
- ✅ Compact tankless design fits narrow UK sink cupboards
- ✅ Built-in alkaline remineralisation improves taste for me
- ✅ 700 GPD rated capacity
- ✅ Fast real-world dispensing — ~2.90 L/min in my latest test
- ✅ 2:1 pure-to-drain ratio (Waterdrop specification)
- ✅ Smart faucet displays TDS and filter-life information
- ✅ PFOA/PFOS reduction supported by SGS testing
Cons
- ❌ Requires a power socket under the sink
- ❌ Requires a drain connection for RO wastewater
- ❌ Pump noise is noticeable while dispensing
- ❌ Replacement filters are proprietary
- ❌ Higher upfront cost than basic carbon under-sink filters
Ready to upgrade your water?
Verdict: Is the Waterdrop G5P700A Worth It?
Yes — I would buy the G5P700A again. After six months of daily use, it remains one of my favourite under-sink RO systems because it combines a genuinely compact tankless design with fast dispensing and built-in remineralisation.
My latest test measured approximately 250 ml in 5.18 seconds, equivalent to around 2.90 L/min, while filtered water measured 22 ppm TDS from incoming water of around 416 ppm. I also prefer the slightly crisper taste of the remineralised G5 water compared with the flatter-tasting water from the countertop K19.
The main drawbacks are the higher upfront price, the need for power and a drain connection, and audible pump noise while dispensing.
Waterdrop currently rates the G5P700A at 700 GPD with a 2:1 pure-to-drain ratio. The system uses a 0.0001 μm RO membrane, and Waterdrop states that SGS testing supports reduction of PFOA and PFOS.
Best for: households wanting a compact under-sink RO system with fast flow and remineralised drinking water.
Less suitable for: anyone wanting the cheapest possible filtration system, a no-plumbing countertop option, or whole-house limescale protection.
My rating: 4.5/5
You’ll be taken directly to the Waterdrop G5P700A product page on the official UK store. Buying direct from Waterdrop UK often includes a longer warranty and faster customer support.
Prefer Amazon Prime delivery? Check price on Amazon.
Check Price on AmazonFAQ
Is the Waterdrop G5P700A suitable for UK plumbing?
Yes – it connects easily to 3/8-inch UK cold-water feed lines and includes adaptors. Most installers complete fitting in under an hour.
How much water does the G5P700A waste per litre of filtered water?
Waterdrop specifies a 2:1 pure-to-drain ratio, meaning roughly two parts purified water for every one part sent to drain. I haven’t independently measured the wastewater ratio.
Are Waterdrop RO systems good for UK hard-water homes?
Yes — Waterdrop units like the G5P700A and G3P600 perform extremely well in UK hard-water. They remove dissolved solids, chlorine, heavy metals and taste/odour issues.
Does the G5P700A reduce TDS to zero?
It produces low-TDS water, but the exact reading depends on the incoming supply and the remineralisation stage. In my tests I recorded around 15 ppm previously and 22 ppm in my August 2026 retest.
Is Waterdrop G5P700A worth it in the UK?
Yes — the Waterdrop G5P700A is widely considered one of the best premium under-sink reverse osmosis systems available in the UK, especially for households in hard-water areas.
It combines a compact tankless design with a high filtration capacity of up to 700 gallons per day, making it suitable for families or heavy daily water use. The built-in alkaline remineralisation stage also improves taste by restoring minerals removed during reverse osmosis.
While the upfront cost is higher than many traditional RO systems, the long-life filters, reduced wastewater and strong performance usually make it good long-term value for UK homes.
Which is better, G5P700A or G3P600?
I prefer the G5P700A where cupboard width and remineralisation are priorities. It is rated at 700 GPD and includes alkaline remineralisation. The G3P600 is rated at 600 GPD, is also tankless, and is a good alternative if you don’t need the G5’s built-in mineral stage.
How long do Waterdrop filters last?
Waterdrop currently specifies around 6 months for the G5P700A CF filter and around 24 months for the RO membrane, although actual life depends on usage and incoming water quality. The smart faucet also monitors filter life and indicates when replacement is due.
Is installation DIY-friendly?
Yes — most UK homeowners install it in under 1 hour with basic tools.
Does the Waterdrop G5P700A really produce alkaline water?
The remineralisation stage adds minerals back after RO filtration, which in my experience gives the water a slightly crisper taste.
Is tankless RO better than traditional tank RO systems?
Tankless reverse osmosis systems like the Waterdrop G5P700A offer several advantages compared to traditional tank-based RO systems, but the best choice depends on your needs.
Tankless systems usually provide:
Faster water flow, More compact under-sink installation, Reduced risk of stale stored water and Lower wastewater ratios
Traditional tank RO systems can sometimes offer:
Lower upfront cost, Simpler mechanical design, Stored water reserve during power cuts
For most modern UK kitchens, tankless RO systems are becoming the preferred option due to space savings and convenience, especially in smaller under-sink cupboards.
Check Your Local Water Hardness
Before choosing a filtration system, it’s useful to know how hard your local water supply is.
👉 Use the UK Water Hardness Checker to see hardness levels by postcode.
