The best reverse osmosis system UK: a plumber’s perspective
- Plumberly
- 2 days ago
- 8 min read
As plumbers, we’re regularly asked which RO systems are actually worth it long term — not just on paper, but in real kitchens, with real pipework, real cupboards and real maintenance over time.
We’ve noticed more and more customers asking us to install reverse osmosis (RO) systems in their homes. There’s a clear growing trend of homeowners wanting the cleanest possible drinking water. If you’re concerned about things like fluoride, nitrates or microplastics, this is one of the most powerful filtration options available.
In this guide, we’re sharing a practical, plumber-led comparison of two popular reverse osmosis systems we’ve been asked to install for customers:
Waterdrop G2P600 Fast Flow RO System
iSpring RCC7AK 6-Stage Reverse Osmosis System
We’ve installed these systems and worked with them in real homes, so this comparison is based on hands-on experience — not just specs.
This guide is for you if:
You want the cleanest possible drinking water
You want to understand tankless vs traditional RO systems
You want experience from a plumber, not a salesperson
What is a reverse osmosis water filter?
Reverse osmosis is one of the most effective forms of water filtration available for homes. It works by forcing water through a membrane that removes a very high percentage of dissolved solids and contaminants.
RO systems can significantly reduce:
Heavy metals
Chlorine and chloramines
PFAS
Microplastics
Nitrates
Fluoride
Total dissolved solids (TDS)
Calcium and magnesium that cause limescale in kettles and appliances (a particular concern for our customers in Poole and Bournemouth)
That’s why many people choose RO systems specifically for drinking and cooking water.
What we look for as plumbers when recommending an RO system
From years of fitting, maintaining and troubleshooting plumbing systems, these are the factors that actually matter in day-to-day use:
Flow rate (how long you’re waiting for a glass of water)
Tank vs tankless design
Space required under the sink (a big one in UK kitchens)
Ease of installation
Ease of filter changes
Waste water efficiency
Noise and vibration
Long-term reliability
Plumber’s quick verdict:
For most UK homes, the Waterdrop G2P600 is the better choice thanks to speed, space-saving design and easier maintenance. Traditional tank systems still suit some users, but they’re less practical in modern kitchens.
What we see go wrong over time (and why it matters)
From a plumber’s point of view, most problems with reverse osmosis systems don’t come from how well they filter — they come from poor installation, awkward layouts, or systems that are simply a pain to live with.
The most common issues we see are filters not being changed, pipework squeezed in where it shouldn’t be, or small leaks going unnoticed under the sink. That’s why ease of installation, tidy pipe routing and simple filter changes matter just as much as filtration performance.
If a system is easy to live with, it’s far more likely to keep working properly long term.
With that in mind, here’s how the two systems compare.
Waterdrop G2P600 fast flow RO system
This is a modern, tankless reverse osmosis system, and one we’ve personally installed.
What stands out straight away
600 GPD fast flow rate - this is genuinely impressive. It fills a glass in seconds rather than waiting for a storage tank to refill.
Tankless design - no bulky pressure tank taking over the cupboard — a huge advantage in most UK kitchens.
Compact and space-saving - ideal if you don’t have much room under your sink to work with.
Installation experience
From a plumber’s point of view, the Waterdrop system is well designed:
Clear instructions
Push-fit style connections
Minimal pipework
Easier to fit neatly than traditional RO systems
It’s one of the more straightforward RO installs we’ve come across. If you’re fairly handy, you could install this yourself using the Waterdrop instruction videos.
If you’d prefer peace of mind, professional installation typically costs £100–£150, depending on your setup.
Filter changes and maintenance
This is where Waterdrop really shines:
Twist-and-click filter changes
No tools needed
Minimal mess
When filters are easy to change, people actually keep on top of maintenance — which matters for both water quality and system lifespan.
Efficiency and waste water
Better filtered-to-waste water ratio
Roughly 2 glasses filtered = 1 glass wasted
Lower ongoing water waste than traditional RO systems
This system uses a small electric pump (very low energy use), so there’s a small increase in electricity usage.
(Fast, tankless RO system ideal for UK kitchens)
iSpring RCC7AK 6-stage reverse osmosis system
This is a classic, tank-based RO system and one of the most popular and well-reviewed RO systems available on Amazon.
What stands out straight away
Tank creates a larger footprint - a bulky storage tank that takes up a lot of cupboard space.
Slower output - at 75 GPD, output is considerably slower.
Built-in remineralisation - adds minerals back after RO filtration.
(Worth noting: Waterdrop offers an optional remineralisation filter if this is important to you)
Installation experience
From a practical plumbing perspective:
More pipework
More joints
More components to fit and test
iSpring states it’s suitable for DIY installation, but you need to be confident and patient. Professional installation typically costs £200–£300, as it takes longer to install neatly and safely.
Filter changes and maintenance
More stages = more filters
Filter changes take longer
More opportunity for mess and leaks
Efficiency and waste water
Roughly 2 glasses filtered = 6 glasses wasted
Higher ongoing water and sewerage costs
No electricity required
It works well, but it’s less efficient by modern standards.
(Traditional tank-based RO with remineralisation)
Waterdrop G2P600 vs iSpring RCC7AK side-by-side comparison
Feature | Waterdrop G2P600 | iSpring RCC7AK |
Flow rate | 600 GPD (very fast) | 75 GPD (slower) |
Design | Tankless | Tank-based |
Space required | Compact | Large footprint |
Ease of filter changes | Very easy | More effort |
Waste water efficiency | Good (2:1) | Bad (2:6) |
Smart display | Yes | No |
Remineralisation | Optional add-on | Included |
Ease of installation | Easier | Harder |
Electricity needed | Yes | No |
Typical plumber install cost | £100–£150 | £200–£300 |
Best for | Modern UK kitchens | Large cupboards / traditional setups |
Running costs: what people don’t always think about
Over time, the real cost of an RO system isn’t just the purchase price. Waste water, filter replacements and servicing all add up — especially in metered homes.
Traditional tank-based systems tend to waste significantly more water and take longer to maintain. More efficient, tankless systems generally waste less water and are quicker to service, which often makes them cheaper and easier to live with long term.
Waterdrop vs iSpring: which is the best reverse osmosis system for UK homes?
Choose the Waterdrop G2P600 if:
You want fast, on-demand filtered water
You have limited cupboard space
You want simple, clean filter changes
You prefer a modern, tidy installation
You’re able to get an electricity supply to the device
Choose the iSpring RCC7AK if:
You have lots of cupboard space
You specifically want built-in remineralisation
You’re happy with slower output
You prefer a traditional RO setup
You’re willing to invest time in filter changes
A plumber’s honest verdict
For most UK kitchens, the Waterdrop G2P600 is the better all-round system. It’s faster, more compact, easier to maintain, and far better suited to modern homes.
The iSpring still has its place — especially for those who prioritise remineralisation — but it’s less practical for everyday use in smaller UK cupboards.
Ross Milne, owner and senior plumber at Plumberly, says: “From a plumber’s point of view, the best solution is the one people will actually live with and maintain long term.”
“We’ve installed both types of systems, and in most UK kitchens the best reverse osmosis system is a tankless design like the Waterdrop. That's because it’s quicker, takes up less space, and people are far more likely to keep on top of filter changes.”
Who shouldn’t buy RO
Reverse osmosis systems take filtration to a whole new level — stripping almost everything out of the water, including minerals. They’re not right for everyone.
RO may not be the best option if:
You won’t keep on top of changing filters
You want to retain naturally occurring healthy minerals
You don’t have space under your sink
You’re very conscious of water waste and prefer a zero-waste system
In these cases, an inline filter like the Water2 may be a better option. These are a smaller, cheaper and less complicated setup that reduce many contaminants while keeping healthy minerals, saving space and avoiding water waste. Find out more about the Water2 filter.
Installation: DIY or plumber?
Some confident DIYers can install reverse osmosis systems themselves, but it’s worth knowing:
Tankless systems are generally more forgiving
Tank-based systems often need pipework adjustments
Any leak under a sink can cause serious damage very quickly
If you’re unsure, having a plumber install and test the system properly can save time, stress and potential water damage. We’re always happy to advise or help with installation across Poole, Bournemouth and Christchurch.
FAQs
Do reverse osmosis (RO) systems remove limescale?
Yes — for the water they filter.
Reverse osmosis systems remove calcium and magnesium, which are the minerals responsible for limescale. That means RO water won’t leave scale behind in kettles, coffee machines or on glassware.
It’s worth noting that RO systems are usually installed for drinking and cooking water only, so they won’t stop limescale elsewhere in the home (showers, taps, boilers). For whole-home limescale control, a water softener or inhibitor would be needed.
Are RO systems safe to drink?
Yes, reverse osmosis water is safe to drink.
RO systems are widely used in homes, hospitals and commercial settings around the world and remove a very high percentage of contaminants.
Because RO removes almost everything from the water — including minerals — some people choose systems with remineralisation stages or get minerals from their diet instead. For most people, this isn’t a problem, but it’s something to be aware of.
Reverse osmosis sorts drinking water — how else can I protect my home from hard water?
Reverse osmosis is excellent for drinking and cooking water, but it only treats water at a single tap. Hard water still flows through the rest of your home — including showers, taps, toilets, washing machines and heating systems — where limescale can continue to build up.
For showers in particular, many households choose a shower filter like Hello Klean. These are designed to improve water quality where you feel hard water most — on your skin and hair — without altering your plumbing or installing a full water softener. Find out more about how Hello Klean works.
Do RO systems waste a lot of water?
Some do — but modern systems are much more efficient than older ones.
Traditional tank-based RO systems can waste 3–4 litres of water for every litre filtered. Newer tankless systems are far more efficient. For example, some modern designs waste roughly 1 litre for every 2 litres of filtered water.
If you’re on a water meter, waste-water efficiency is an important factor to consider when choosing a system.
Do RO systems need electricity?
It depends on the type of system.
Tankless RO systems usually require electricity to power an internal pump. Energy use is very low, similar to a small kitchen appliance.
Traditional tank-based RO systems do not require electricity and rely on water pressure alone.
This can affect where the system can be installed and whether you need a nearby power supply.
Can a plumber install a reverse osmosis system?
Yes — and in many cases, it’s recommended.
Some RO systems are marketed as DIY-friendly, but installation can involve:
Cutting into cold-water pipework
Adding drain connections
Ensuring correct water pressure
Preventing leaks under the sink
A plumber can install the system neatly, test it properly, and make sure it’s safe and leak-free — which is especially important given how much damage an unnoticed leak can cause.
We regularly install RO systems for customers across Poole, Bournemouth and Christchurch and are always happy to advise on the best setup for your kitchen.
We're here to help with RO installations
If you're looking for reverse osmosis system installation in Poole, Bournemouth or Christchurch - just give us a call on 01202 985368 or drop us an email to hello@plumberly.co.uk.
Let us know the model you've chosen and we'll give you a free installation quote.
