The complete guide
How To Choose An Under Sink Water Filter For Your Kitchen
The problem with tap water that is perfectly fine
Most mains water in the UK is drinkable the moment it leaves the tap. That is not the issue. The issue is that it often tastes of the process that made it drinkable, and that flat, slightly chemical note shows up everywhere. It is in the glass of water you pour at ten at night. It is in the tea, where it dulls the flavour. It is in rice, in stock, in ice cubes that come out of the freezer smelling faintly of the swimming baths.
Plenty of households deal with this by buying a jug filter. Jugs work, up to a point. Then somebody puts an empty one back in the fridge, or you want two litres for a pan and the jug gives you half, or the lid cracks and you discover the replacement costs nearly as much as the jug did. A plumbed-in under sink water filter removes all of that friction. The water arrives already filtered, every time, and the hardware lives behind a cupboard door where you never have to look at it.
How a ceramic candle filter works
This system uses a ceramic candle cartridge. The name comes from the shape: a hollow ceramic cylinder that water enters from the outside and leaves through the middle. Ceramic has been used in domestic filtration for a very long time, mostly because the material gives water a slow, even path to travel rather than letting it rush through.
In this product the cartridge is designed to reduce chlorine taste and odour and sediment from drinkable mains water. That is the honest scope of it, and it is also the part you notice. Sediment is the fine grit that can arrive after street works or a mains repair. Chlorine taste and odour are the everyday background flavour. Take those down and water starts tasting of nothing in particular, which is exactly what you want from water.
One important boundary: this is for use with drinkable mains (town) water. It is not a treatment for untreated supplies like rainwater, bore water or anything from a river or stream. If your supply is not already fit to drink, this is the wrong product and you need advice from a water treatment specialist instead.
Why it has to be fitted by a plumber
This connects to your mains plumbing, so a qualified plumber must install it. It is worth saying plainly rather than burying it in the small print.
There are a few reasons. The connection has to be made properly into the cold supply, under pressure, inside a cupboard that usually already contains a waste trap and sometimes a dishwasher or washing machine feed. A plumber will fit or check an isolating valve so the system can be shut off for cartridge changes. They will also position the housing with enough clearance above and around it that you can actually unscrew the bowl later, which is the sort of detail that only becomes obvious six months in when you cannot get a hand around the back.
The installation kit comes in the box, so the fittings are there. What the plumber brings is the judgement about where it goes and how it is connected. The maker states that the system is WRAS approved, and your plumber will install it according to the maker's instructions.
Measure the cupboard first
The listed product dimensions are 30cm deep, 30cm wide and 60cm high. That is a real footprint, not a small inline canister, so the measuring tape comes out before the credit card.
Open the sink cupboard and look at what is genuinely free. The waste trap usually eats the middle. Boiler pipework or an appliance hose may run down one side. Some kitchens have a false floor or a plinth drawer that steals height. What you are checking is whether there is a clear volume of roughly 30 by 30 by 60 centimetres, plus a bit of working room so the plumber can get a spanner in.
If the sink cupboard is full, ask your plumber whether an adjacent base unit could take it with a short pipe run. That is a judgement call for the person doing the work, not something to assume from a product page.
Who this suits
A plumbed-in system makes most sense for households that drink a lot of tap water. Families, people who make a pot of tea three times a day, anyone who cooks properly and uses litres of water in a week rather than a glass or two. The more water you get through, the more a jug starts to feel like a chore and the more an under counter water filter earns its place.
It also suits kitchens where worktop space is precious. Filter jugs, countertop units and bottled water all need somewhere to sit. This does not. Once it is in, the cupboard door closes and the kitchen looks the same as it did before.
It suits less well if you are renting short term, if your sink cupboard is already packed, or if you are not able to arrange a plumber. There is no shame in a jug if that is the realistic option for your home right now.
Living with it
Day to day, there is nothing to do. No power, no refilling, no buttons. You use the tap and the filter does its job quietly behind the door.
The one ongoing task is the cartridge. A ceramic candle is a consumable and needs replacing on the maker's schedule, which is set out in the documentation that comes with the system. Keep to that schedule and the filter performs as intended. Stretch it and you will usually notice before anything else does, either in the flow or in the taste coming back.
Changing a cartridge is normally a short job once the system is installed. Shut the supply off at the isolating valve, swap the candle, open the valve again slowly and run the first few litres to waste so any loose material is flushed out. If the house has been empty for a holiday, run the tap for a bit before you drink from it. Wipe the housing with a damp cloth when you are cleaning the cupboard and glance at the fittings for any sign of a drip.
Questions worth asking before you buy
Two practical ones. First, will the plumber be fitting a separate drinking tap or connecting into an existing one? Clear that up in advance so any extra parts can be ordered before they arrive rather than after. Second, where will you buy replacement cartridges, and will you remember? A note in your phone calendar on installation day saves a lot of bother later.
It is also fair to set expectations with the rest of the household. Filtered water tastes different because something familiar has been taken away. Most people prefer it within a day or two. A few find it oddly plain at first, which is really just the absence of what they had been tasting all along.
The short version
This is a ceramic candle system that lives in your sink cupboard and treats drinkable mains water on its way to the tap. It is designed to reduce chlorine taste and odour and sediment, so water, tea and cooking all taste cleaner. It measures 30 by 30 by 60 centimetres, comes with an installation kit, and the maker states it is WRAS approved.
Three things to do before you order. Measure the cupboard. Book a qualified plumber, because this connects to mains plumbing and must be installed by one. Plan for cartridge replacement on the maker's schedule. Get those sorted and you have a filter that asks almost nothing of you and quietly improves every glass of water in the house.