Trusted Reviews is supported by its audience. If you purchase through links on our site, we may earn a commission. Learn more.

Zip HydroTap G4 boiling tap Review


rating-star rating-star rating-star rating-star rating-star


  • Consistent hot water temperature
  • Pumped high flow rate
  • Staggeringly good water filter
  • Better-tasting water and tea
  • Lively sparkling water
  • Perfect drip-free tap
  • Intuitive tap controls
  • Many tap designs available


  • Fan noise
  • High price

Key Specifications

  • Review Price: £3442
  • Boiling, chilled and sparkling water
  • 0.2-micron water filter
  • Arc designer HydroTap
  • LED touch-button selection
  • Colour touchscreen controls
  • Three energy saving modes
  • 3-year guarantee (5-year on boiler)

What is the Zip HydroTap G4?

For top-end kitchens looking for the ultimate worktop gadget, Zip’s HydroTap G4 delivers filtered boiling, chilled and sparkling water. Combining a stylish touch button-controlled tap and touchscreen Command Centre boiler, the system is comprehensive, efficient and super-cool.

The G4’s performance and energy efficiency are outstanding. It delivers peerless filtration, consistent hot water and superb-tasting chilled and sparkling water. The chiller, fan and water pump do make the G4’s Command Centre a little noisier than a fridge – and that price is eye-watering. But for instant, drip-free water for drinking, hot beverages and cooking, Zip’s HydroTap  G4 is simply the best.

Zip HydroTap G4 – Design and features

Zip is an Australian brand that’s been making instant hot water systems since 1947; it’s credited for creating the world’s first boiling water tap in 1970. The company has been making under-counter filtered boiling and chilled water systems since 1996. If you’ve used a boil tap in an office, it was probably a Zip.

The HydroTap G4 is Zip’s flagship entry into boiling water taps for home kitchens. While the G4 can be specified in a number of delivery configurations, on test is the full-fat version. This offers filtered hot, filtered chilled and filtered chilled, sparkling water.

The G4 is a stand-alone system, and as such it doesn’t integrate into your mains hot and cold water taps. While you can have the G4 tap over a sink, it’s slicker to have it installed with its own dedicated font.

And we do mean ‘have it installed’. The system is frighteningly complex to install and commission. Even someone with good plumbing skills will lack awareness of the intricacies of the setup. Zip’s installation service will set you back £262.80. Nevertheless, it’s more than worth it for the slick install, peace of mind and one-to-one tutorial.

The HydroTap G4 system as installed in our lab comprised of four key parts. The tap itself, the font, the boiler/chiller unit and the CO2 canister for the sparkling water.

We were supplied a Zip Arc tap in a contemporary matte black. The Arc series alone offers 12 finish options, plus there are another four complete Zip tap ranges from which you can make your choice. You certainly won’t struggle to find a tap design (and matching font if required) to suit your kitchen.

The swan neck on the Arc tap is fixed in position after installation. It can be set up with the controls on either side, or even at a jaunty angle by the installer. The controls are made up of rubberised illuminated touch buttons and a smooth rotating tap. The upper button scrolls through the three dispensing modes with accompanying colours: blue is the default and signifies it will dispense chilled water; white indicates chilled sparkling water; red is for hot water. It’s possible to set up a safety system where the second button acts as a child lock.

The handle rotates forward and holds to dispense for a set amount of time, offering hands-free filling if required. We opted for 15 seconds for both hot and cold for our tests. Yet the G4’s stellar flow rates mean you may wish to opt for a rather shorter period for filling cups and glasses. Push the lever backwards and it dispenses until you let it go.

All water dispensed through the G4 is filtered. The large cartridge filter is housed inside the main boiler/chiller unit for a neat installation. It will filter out particles down to an incredibly small 0.2microns – that’s around 25x finer than a standard jug water filter. This pulls out chlorine, heavy metals, impurities and even larger bacteria, to leave water odour-free and better tasting. The filter is good for around 6000 litres of water.

A pump pushes water through the G4’s super-fine filter; mains pressure would be reduced to a dribble without it. Even with relatively low mains pressure here to start, the G4 pushed through a copious amount of hot and cold water. Only the sparkling system showed any reduction in flow rate.

The boiler unit, or Command Centre as Zip refers to it, is huge. It took up half a double-width cupboard. It also required a large cut-out and vent installation in the floor of the cupboard to ventilate the chiller mechanism.

Alongside the boiler, the chiller system uses a compressor just in the way of a fridge. This features a large cooling fan and cleanable air filter to the right side of the Command Centre. It is possible to adjust fan speed, but even at its lowest 50% setting, noise was obvious. Add to this the sound emitted from the compressor and water pump, and the G4 Command Centre is far from silent at around 50-52dB. It didn’t help that our test cabinet didn’t have doors though, so expect 6-10dB less than that figure from a shut cupboard.

Setup and control of the G4 Command Centre is via a colour touchscreen display. It plugs into a normal 13-amp mains socket and there’s no need to vent it into your waste plumbing. For extreme hard water areas there’s an optional limescale filtration system available.

The final piece in our G4 setup was the CO2 canister for sparkling water. This contains 1kg of carbon dioxide, which is injected into the stream of chilled, filtered water to give you a steady stream of lightly sparkling soda water. Each cylinder is good for up to 100 litres of sparkling water.

At close to £3500, plus installation and ongoing filter and CO2 canister costs, there’s no doubt that the Zip HydroTap G4 is a top-end luxury purchase for the kitchen. Thankfully the design, features and technology deliver equally top-end results.

Zip HydroTap G4 – What’s it like to use?

The HydroTap G4 is super-comprehensive in its features, options and controls. The colour touchscreen that features on the Command Centre is deep with multi-layer menus offering a wealth of usage information.

You can set up how long the auto-dispense time runs for, engage the safety system on the tap, check your filter and CO2 usage, analyse energy consumption, and examine the system log, which will highlight issues such as power outages. There’s a continuous auto-diagnostic system running in the background, and you can lock off the touchscreen with a pin code if required.

Zip has gone a long way to maximise energy efficiency with the G4 system. You can set up timed power-off periods, or use the automatic sleep mode that reduces power consumption after two hours of inactivity. Our favourite energy-saving system is the Lux sensor. This automatically puts the unit to sleep when the kitchen lights go out at night. It wakes up again as light levels increase in the morning.

Chilled water temperature is factory set at 3-5ºC (adjustable up to 14ºC), while hot water is set at 98ºC. The G4’s Power-Pulse electronics claim to keep hot water temperature within 0.2ºC of set, and it continuously auto-calibrates to adjust for ambient conditions.

Why only 98ºC and not boiling? To achieve WRAS approval in the commercial environment, you can’t dispense water above 98ºC for safety and energy efficiency. While this isn’t essential in a home environment, keeping water at 98ºC reduces power consumption compared to 100ºC models. The extra energy required to physically boil water (change its state) is much higher than that required to simply raise it by two degrees.

In practice, we found the 98ºC temperature had other advantages too. As a smooth stream of water emerged from the tap – as opposed to a mix of steam and water – it didn’t splash or spit in the manner of true boiling water models. And, being a tea purist, I also found that the taste of my cuppa was improved by the water being just below boiling.

The Arc tap itself is faultless – and really cool. The coloured indicators and smooth action of the tap lever feel great. If you let go of the lever from the pushed-back continuous flow mode then it pops straight back to the off position with no over-run. The timed dispense in the forward position worked perfectly to the second. Plus, the tap itself remained impressively cool to the touch, even after having dispensed a lot of hot water.

The HydroTap’s pumped water system means that the G4 dispenses hot and chilled water at more than twice the rate of any other hot tap we’ve tested. Dispensing stops instantly, with no over-run or dribbling. The CO2-injected sparkling water does splatter a little more than ‘still’ water, and there ‘s a little over-run after shutoff while the CO2 gas in the pipe pushes out some last drops.

If you want to delve into the G4’s menus then there’s certainly something of a learning curve to negotiate. Yet, you don’t actually need to. With the installer managing all of your key settings, chances are it will be a fit and forget unit until the filter or CO2 cartridge need to be change – both relatively simple DIY tasks with a little menu fettling to purge the system and reset counters.

Apart from the noise emitted by the chiller fan and water pump, we really couldn’t fault the Zip HydroTap G4’s day-to-day convenience, effectiveness and ease of use.

Zip G4 Hydrotap – How well does it perform?

That pumped water system pushes water through the super-fine filter at a serious rate, making the G4 the fastest dispensing boil tap system we’ve tested by far. Even fed by our low 2.5-bar water pressure, a 15-second dispense delivered more than 0.8 litres of hot water, 0.7 litres of chilled and 0.35 litres of sparkling of water. That’s a superb hot water flow rate of well over 3 litres per minute.

To keep your hot water hot, the G4 simply reduces flow rate on multiple long dispenses rather than delivering cooler temperature water. Using a 15-second dispense followed by 1-minute rest cycle, flow rate began to reduce by about 0.1 litres/15 seconds by the fourth cycle and beyond. However, hot water temperature never faltered from 97-98 degrees throughout.

Give the G4 a little more than a minute or so between 15-second dispenses and it continued to deliver water at near-0.8 litres/15 seconds at almost exactly 98 degrees. Brilliant.

Having cold water quite literally on tap was ideal in the hot summer period throughout the test. Moreover, Zip’s 0.2-micron water filter works exceptionally well. Cold water taste was significantly improved over mains tap water, with no smell of chlorine remaining at all. Jackie, myself and several passers-by we roped in as taste-testers all agreed that it was like drinking the very best bottled mineral water. High praise indeed.

Cold water did suffer a greater change in temperature the more you dispense. It simply takes longer to chill water down than to heat it up. Our first 15-second burst came in at 6ºC, with each subsequent 15-second delivery (after 1 minute rest) creeping up by a degree or two. In the unusually hot July period of the test, the cold water was a degree higher than the 3-5ºC set.

Sparkling water flow is slowed by the process of infusing it with CO2. Delivery was around 0.35 litres/15 seconds. Filling a pint glass took about 20 seconds. The sparkling water could be a bit lively coming out of the tap to start with and there was a very small amount of run-on when the tap was turned off. Neither were big issues and there was little splashing outside of our test pint glass.

The result was a crystal-clear glass of chilled, filtered and lightly sparkling water. Fizz bubbles are quite small and ‘sparkly’, rather than big and bold. We likened this to San Pellegrino bottled water as opposed to more gassy soda water. For drinking straight-up it was ideal. For having in a white wine spritzer… well, it worked just fine for that too.

 Zip HydroTap G4 – How much will it cost to run?

High-tech insulation, Power-Pulse electronics, timed power-off modes, auto-sleep function and a Lux-based standby feature go a long way to keeping the G4 energy efficient. After all, this is a boiling water system, pump, fan and a small refrigeration unit all in the one box.

With the chiller unit running it was difficult to compare running costs with other boiling water-only taps directly. Using the auto-sleep function, the G4 unit drew a standing 0.8kWh per day without drawing off any water. Further savings can be made if you use the time power-off function too.

We set the menu to power-down outside of the lab opening hours (7pm-9am), which reduced standing power consumption to just below 0.7kWh per day. That’s about 10.5p per day or around £38 per year. That’s almost exactly the same as Franke’s Omni 4-in-1 boiling water-only tap.

Direct water-heating costs are comparable to any other boil tap, since they’re over 95% efficient in turning electricity into hot water. That compares to induction hobs at 90%, kettles at 82%, standard ceramic hobs at 74% and gas hobs at a grim 55%.

Since the G4 keeps to 98ºC, it saves some energy in not taking the water to boiling. Delivering 20 litres of 98ºC water per day will cost about 1.8kWh or 27p to heat. That’s just over £80 for 300 days in use per year. We estimate that dispensing 3 litres of chilled water per day will add about £20 per year to those costs. Total energy running costs based on this usage would be around £140 per year.

Okay, let’s not forget this system is nearly £3500 to purchase including the font plus over £250 to install. It will also have ongoing costs in filters (around £95 per cartridge) and CO2 canisters (approx £45 per cylinder). Alternatively, Zip offers a HydroCare package at £15/month that covers breakdowns, annual filter replacement, sanitising and annual limescale management.

The Zip HydroTap G4 is an unashamedly high performance, luxury item. Thankfully its features, functionality and performance more than live up to the cost.

Should I buy the Zip HydroTap G4?

The Zip HydroTap G4 is expensive. Yet the sheer convenience of super-consistent boiling, chilled and sparkling water on tap is addictive. Ongoing running costs aren’t much higher than standard boil-only hot taps thanks to the G4’s excellent efficiency.

The pumped filter is frankly amazing, since it turns mains supply into the best tasting mineral water. The flavour of your brew is markedly improved and sparkling water is a refreshing alternative to plain old H2O. The illuminated, touch-control Arc tap is intuitive, drip-free and just about the coolest kitchen gadget we’ve seen to date.

As with many super-premium kitchen appliances we’ve tested, if you appreciate the finer things in life then you get what you pay for. The Zip HydroTap is unquestionably the very best multi-function boil tap on the market.


Outstandingly good and eye-wateringly expensive in equal measure, Zip’s HydroTap G4 offers perfect filtered hot, chilled and sparking water from a super-cool, luxury tap.

Trusted Score

rating-star rating-star rating-star rating-star rating-star

Why trust our journalism?

Founded in 2003, Trusted Reviews exists to give our readers thorough, unbiased and independent advice on what to buy.

Today, we have millions of users a month from around the world, and assess more than 1,000 products a year.

author icon

Editorial independence

Editorial independence means being able to give an unbiased verdict about a product or company, with the avoidance of conflicts of interest. To ensure this is possible, every member of the editorial staff follows a clear code of conduct.

author icon

Professional conduct

We also expect our journalists to follow clear ethical standards in their work. Our staff members must strive for honesty and accuracy in everything they do. We follow the IPSO Editors’ code of practice to underpin these standards.