How it differs from a standard cartridge filter
A normal under-sink filter works by passing water through media. Sediment stages catch particles; carbon stages take out chlorine and the taste and odour that come with it. The water goes in one end and out the other at mains pressure, and that is the whole arrangement.
Reverse osmosis adds a membrane stage. Water is forced against a very fine membrane, and what passes through is separated from what does not. The part that does not pass through has to go somewhere — that is the drain connection, and it is the single biggest practical difference between the two systems.
Because the membrane works slowly compared with a tap running, reverse osmosis units store what they make. That is the tank. It sits under the sink with the unit, it has to be plumbed in, and it is the reason this system needs meaningfully more cupboard room than a cartridge housing.
If what is actually bothering you is the chlorine taste, a standard under-sink unit does that job for less money and in less space, and we will tell you so. Under sink water filter installation
What it needs under the sink
Room for the unit and the tank
This is the constraint that stops more of these jobs than anything else. A kitchen sink cupboard in a Kardinya house — a suburb built out in quadrants from October 1967 through the 1980s, and renovated at least once since in most cases — is usually already carrying a waste trap, a dishwasher hose and a bin. A reverse osmosis unit plus its tank wants more space than people picture.
A drain connection
The membrane's reject water goes to waste, which means a connection into the sink waste. It is a standard arrangement and it is done every day, but it is a connection that a plain cartridge filter simply does not have, and it has to be made properly rather than improvised.
A dedicated tap
Reverse osmosis water comes out of its own spout. It does not get plumbed back through your mixer. So a filtered tap is part of this job rather than an option on it, which means a hole in the benchtop — routine on laminate, slower and more careful on stone. Filtered tap installation
A cold feed with isolation
Same as any under-sink system. On an older kitchen the existing isolation may need attention first, and that belongs on the quote rather than turning up on the day.
Whether it is worth it for your house
Straight answer: for a lot of Kardinya households, a standard carbon filter is the right tool and reverse osmosis is more system than the problem needs.
Where it earns its place is with a household that wants purification beyond taste and odour, and has decided that on purpose rather than because somebody sold it to them. That is a legitimate choice and we fit them.
What we are not going to do is tell you the mains supply is unsafe in order to sell you the bigger unit. Water Corporation adds chlorine to all of its supply schemes as a disinfectant, and the treated supply reaching Kardinya is monitored. Filtration here is about taste, odour, sediment and what you would prefer to drink — not about rescuing you from the tap.
How the job runs
You ring or send the form
Tell us whether you are set on reverse osmosis or still weighing it up against a standard cartridge unit. Either answer is fine.
A licensed plumber comes out at no charge
He measures the cupboard properly, looks at the waste and the cold feed, and looks at the benchtop for the tap.
You get a written price on site
Itemised, before anything is touched. Transparent pricing, no hidden costs — with this system in particular, the tap and the drain connection are part of the job and they belong on the page you sign, not in a phone call afterwards.
We fit it
Unit and tank mounted where they can be reached, cold feed connected and isolated, drain connection made, dedicated tap fitted to the benchtop.
Commissioned properly
A reverse osmosis system needs flushing through before the water is worth drinking, and the tank needs to fill and be checked. Everything is tested under pressure before we leave.
Paperwork
The manufacturer's documents for the unit, and a straight answer about when each stage is next due.
Servicing afterwards
Reverse osmosis has more consumables than a cartridge filter, and they do not all run out together. The pre-filter stages that protect the membrane are changed more often than the membrane itself, and manufacturers nominate periods for each.
The practical signs are the same as any filter — the flow at the filtered tap drops off, or the tank takes noticeably longer to recover between glasses. When that happens it is a service. Cartridge replacement and servicing
What it costs
The unit and its number of stages, whether the cupboard takes it without rearranging what is already in there, the benchtop material for the tap, and the state of the existing cold feed and waste.
Those are different at every house, which is why there is no figure on this page. A licensed plumber comes out at no charge and you get the real number in writing before anything starts.