What the job actually is
A cartridge housing goes inside the sink cabinet, usually mounted to the side wall of the cupboard rather than sitting on the base. It is fed from the cold water line that already runs to your mixer, and it sends filtered water out to a separate small tap on the sink.
Your existing mixer keeps working exactly as it did. Nothing about the hot side changes. You get one extra tap that delivers filtered water, and a unit in the cupboard that needs a cartridge every so often.
That is the whole system. It is not complicated, which is exactly why it is worth doing properly — the parts that go wrong later are all decisions made in the first hour.
Why the cold feed matters
The filter has to come off the cold line, and it has to come off it through a valve that will shut when somebody needs it to.
On a newer Gosnells kitchen that is straightforward. The isolation valve under the sink is modern, it turns, and teeing off it is a short job.
On the older townsite houses — the 1960s and 70s streets off Albany Highway and around the two stations — it often is not. Those valves have frequently been in place since the kitchen was last done, and a valve that has not moved in twenty years does not always survive being asked to. That is not a reason to avoid the job. It is a reason for the plumber to look at the valve before quoting, so that replacing it is a line on the quote rather than a phone call from under your sink.
We also check what the cabinet will actually hold. Older kitchens have smaller cabinets, and a lot of them have a waste trap running through the middle of the useful space. The unit has to mount somewhere that leaves room to swing a cartridge out later, not just somewhere it fits today.
Why the tap hole matters
The filtered water has to come out somewhere, and that means a hole through the sink or the benchtop.
Some sinks already have a spare knockout, usually where a soap dispenser or an air switch was meant to go. If yours does, this part is easy.
If it does not, a hole has to be drilled, and what the benchtop is made of decides how that goes. Stone is drilled with different tooling and more care than laminate. Laminate needs sealing properly at the cut or the substrate takes on water over the years. Stainless is its own thing again.
This is also where the position gets decided. The tap wants to be somewhere you can get a jug under it, clear of the mixer's swing, and clear of the window if the sink is under one. It is a one-time decision on a permanent hole, which is why we talk about it with you standing at the sink rather than over the phone.
How long it takes
A straightforward install — sound isolation valve, room in the cupboard, existing hole in the sink — is a short visit. You would not need to take the day off.
It gets longer when the valve has to be replaced, when the benchtop needs drilling, when the cabinet has to be worked around, or when the tap position needs a bit of thought. We tell you which of those applies when we quote, so the timing is known before we arrive with tools.
Your cold water is off for part of it, not all of it. Worth knowing if you work from home.
What you get at the end
The unit mounted where it can be serviced, the connections made and tested under pressure, the tap sitting square and turning properly, and the cupboard left dry and tidy.
You also get told when the cartridge will be due and what it is, so you are not standing in an aisle later comparing part numbers. We do the changes ourselves if you would rather not think about it. Cartridge replacement
Is under-sink the right system for you?
If what bothers you is the taste, the smell or the chlorine in your drinking water, then yes — this is the cheapest correct answer and we will say so.
If the problem shows up in the shower, the laundry or on your fittings, an under-sink unit will not touch it, because it only treats one tap. That is a mains question. Whole house filtration
If you want the drinking water treated as thoroughly as it reasonably can be and the cupboard has the room, the conversation is about reverse osmosis instead. Reverse osmosis
Not sure which? That is what the free visit is for. Describe it on the phone, we come and look at no charge, and you get a written price for whichever one it turns out to be.
Why use a licensed plumber
An under-sink filter is a permanent connection into your drinking water. It should be made by somebody entitled to make it, and it should be made in a way that a future plumber can isolate and service without cutting anything.
Plumbing Licence 8396 and Gas Licence 13098, both held by Tim, who does the work himself. The person who quotes it is the person who fits it. $0 call-out fee, free quote, transparent pricing with no hidden costs, Monday to Friday 7:00am to 4:00pm.
All the systems we install · Water filter installation in Gosnells