If you want better-tasting drinking water at home, it is easy to assume you need a large whole-house filtration system.
For many households, you probably don’t.
If your main concern is the water you drink, cook with and put in the kettle, an under-sink filtration system can be a much simpler solution.
Instead of filtering every litre of water entering the property, an under-sink system treats the water at the point where you actually consume it.
That can make a lot of sense for homes across North Lakes, Mango Hill, Griffin, Murrumba Downs, Kallangur, Narangba and surrounding Moreton Bay suburbs.
What Is an Under-Sink Water Filter?
As the name suggests, an under-sink water filtration system is installed inside the kitchen cupboard beneath your sink.
Cold water is diverted through one or more filter cartridges before being delivered either to:
- A dedicated drinking-water tap
- A three-way mixer tap
- In some systems, the normal cold-water outlet
The filtration happens immediately before you use the water.
That is why these systems are also known as point-of-use filters.
Rather than treating water going to the toilet, shower, washing machine, garden hose and every other fixture in the house, you concentrate the filtration where it is most useful.
Why Filter Drinking Water If Brisbane’s Water Is Already Treated?
This is an important distinction.
Installing a drinking-water filter does not automatically mean there is something wrong with the town water supply.
Queensland’s reticulated drinking water is treated and monitored, and chlorine is commonly used by water utilities as part of the disinfection process. Queensland Health notes that chlorine at appropriate concentrations is used to control microorganisms in water distribution systems.
But safe water and water you enjoy drinking are not necessarily the same question.
People can be sensitive to:
- Chlorine taste or smell
- Sediment or fine particles
- Metallic flavours
- General taste and odour
Urban Utilities’ own reporting includes customer enquiries and complaints about chlorine, metallic and chemical tastes and odours.
For many households, the reason for installing an under-sink filter is therefore fairly straightforward:
they want their drinking water to taste better.
What Does an Under-Sink Water Filter Actually Remove?
This depends entirely on the filtration system.
There is no single cartridge that magically removes everything.
Different filtration technologies are designed to deal with different things.
Sediment Filters
Sediment cartridges physically capture particles suspended in the water.
Depending on the cartridge rating, they can help reduce things such as:
- Fine sediment
- Rust particles
- Dirt
- Other suspended material
Think of this as the mechanical stage of filtration.
Queensland Health describes polypropylene and ceramic cartridge filters as being effective at removing sediment, but notes that these basic particle filters do not remove dissolved chemicals.
That distinction matters.
A filter being rated to five microns tells you something about the size of particles it can trap.
It does not mean it removes every substance from the water.
What Does a Carbon Filter Do?
Activated carbon is one of the most common stages used in household drinking-water filtration.
Its job is different from a simple sediment cartridge.
Carbon filtration is often used where the objective is improving the taste and odour of drinking water, particularly where chlorine is noticeable.
This is why many under-sink systems combine filtration stages.
For example:
Stage 1: sediment filtration
Stage 2: activated carbon filtration
Rather than asking how many stages a filter has, however, it is better to ask:
What is each stage designed to do?
A three-stage system is not automatically better than a two-stage system if you do not know what is inside the cartridges.
What About Reverse Osmosis?
Reverse osmosis, usually shortened to RO, takes filtration considerably further.
Rather than simply trapping larger particles or using carbon adsorption, reverse-osmosis systems force water through a very fine membrane.
Queensland Health describes reverse osmosis as capable of removing a broad range of dissolved substances, including sodium, chloride, copper, chromium and lead, while potentially reducing a number of other dissolved minerals and chemicals.
That capability comes with trade-offs.
RO systems are generally:
- More complicated
- More expensive
- Slower than basic filtration systems
- Connected to the drainage system
- Producers of a wastewater stream during filtration
- Dependent on regular cartridge and membrane maintenance
For somebody who simply dislikes the chlorine taste of their kitchen tap water, RO may be considerably more filtration than they actually require.
For somebody with a specific water-quality objective, however, it may make sense.
The correct system depends on what you actually want to remove.
Under-Sink Filter vs Whole-House Filter
This is where homeowners can potentially spend far more than they need to.
Ask yourself one question:
What water are you actually trying to filter?
If your answer is:
“The water we drink.”
Then under-sink filtration may be the logical starting point.
If your answer is:
“Every tap, shower and appliance in the house.”
Then you are talking about whole-home filtration.
They solve different problems.
Under-Sink Filtration
An under-sink system can be a good option if you primarily want:
- Better-tasting drinking water
- Filtered water for cooking
- Filtered water for tea and coffee
- A permanent alternative to filter jugs
- A cleaner-looking solution than a benchtop filter
- Filtration without treating thousands of litres used elsewhere
Whole-House Filtration
A whole-house system treats water before it is distributed throughout the property.
That may be appropriate where there is a reason to treat water supplied to:
- Bathrooms
- Showers
- Laundry
- Kitchen
- Appliances
- Other household outlets
But if your concern is purely drinking water, filtering the water used to flush the toilet probably isn’t achieving much.
A Dedicated Filter Tap or a Three-Way Mixer?
There are two common approaches to delivering filtered water at the kitchen sink.
Option 1: Dedicated Filter Tap
A small additional tap is installed alongside the existing kitchen mixer.
Your normal mixer continues supplying normal hot and cold water.
The smaller tap supplies filtered drinking water.
This is simple and keeps the two systems clearly separated.
The downside is that you need another hole and another tap on the sink or benchtop.
Option 2: Three-Way Mixer Tap
A three-way mixer combines:
- Normal hot water
- Normal cold water
- Filtered drinking water
into one tap assembly.
Internally, the filtered-water pathway remains separate from the standard hot and cold supply.
For homeowners renovating a kitchen or replacing an existing mixer anyway, this can create a much cleaner result.
Why Not Just Use a Filter Jug?
You absolutely can.
For somebody who rents, drinks relatively little filtered water or wants the lowest-cost solution, a filter jug can be perfectly reasonable.
An under-sink system becomes more attractive when you are tired of:
- Refilling the jug
- Waiting for water to filter
- Having the jug take up refrigerator space
- Changing small cartridges frequently
- Running out of filtered water while cooking
An under-sink system effectively turns filtration into part of the kitchen plumbing.
Open the tap and filtered water is available.
What About Bottled Water?
This is another reason people start considering filtration.
If a household regularly buys bottled drinking water because they prefer the taste, the bottles eventually become an ongoing purchase rather than a one-off expense.
An under-sink filter gives you another option:
filter the water already supplied to the kitchen.
It also means you do not need to keep transporting and storing cases of bottled water.
Does Filtered Water Taste Different in Coffee and Tea?
It can.
Water is the largest ingredient in both coffee and tea, so changes in water taste can naturally affect the finished drink.
If your tap water has a noticeable chlorine taste or smell, reducing that taste can change the flavour of:
- Coffee
- Tea
- Cordials
- Ice
- Cooking water
- Drinking water itself
That makes the kitchen the obvious location for point-of-use filtration.
You’re treating the water where taste actually matters.
Don’t Buy a Filter Based Only on the Number of Stages
This is one of the easiest traps to fall into when comparing water filters online.
You will see:
- Two-stage filters
- Three-stage filters
- Five-stage systems
- Seven-stage systems
- Ten-stage systems
A larger number sounds better.
But it doesn’t tell you whether those stages are relevant to your water or what you are trying to achieve.
Instead, ask:
What does each cartridge remove?
What is its rated capacity?
How often does it need replacing?
What is the replacement cartridge cost?
Is the product suitable for Australian drinking-water plumbing?
Those questions matter considerably more than the number printed on the box.
Make Sure the Plumbing Products Are Approved for Use in Australia
This is particularly important with cheap filtration systems purchased online.
Australia’s WaterMark Certification Scheme covers plumbing and drainage products that fall within the scheme. Products required to carry WaterMark certification must be certified before they can legally be installed, and products intended for contact with drinking water must meet the relevant drinking-water material requirements.
Buying an unknown filter system from an overseas marketplace because it looks inexpensive can therefore create problems beyond simply whether the filter works.
The plumbing connections, tapware and components need to be appropriate for the installation.
Filters Still Need Maintenance
Installing a filter isn’t the end of the job.
The cartridges are consumable components.
Over time they collect the material they are designed to remove, and they need to be changed according to the manufacturer’s specifications.
Queensland Health specifically warns that filter cartridges need to be cleaned or replaced according to manufacturer instructions so they continue operating correctly.
Leaving a filter cartridge installed indefinitely defeats the purpose of having the system.
When choosing a filter, look at the ongoing maintenance cost as well as the installation price.
A cheap filter with expensive proprietary cartridges may not be cheap for very long.
Which Under-Sink Water Filter Should I Choose?
Start with what you want the filtration system to achieve.
If your main complaint is chlorine taste or smell:
A quality carbon-based drinking-water filtration system may be worth considering.
If you’re concerned about sediment:
A sediment stage can be added before the carbon filtration stage.
If you want significantly more intensive filtration:
You may want to investigate reverse osmosis.
If you want every water outlet treated:
Under-sink filtration probably isn’t the correct solution and a whole-house system may be more appropriate.
There isn’t one universally “best” water filter.
There is a filtration system that suits your water, your household and what you’re trying to achieve.
Thinking About an Under-Sink Water Filter?
RJT Plumbing & Gas can help homeowners across North Lakes, Mango Hill, Griffin, Murrumba Downs, Kallangur, Narangba and surrounding Moreton Bay areas install practical under-sink drinking-water filtration systems.
Whether you want a dedicated filtered-water tap, a three-way kitchen mixer or you’re trying to work out whether you actually need whole-house filtration, we can help you choose a setup that makes sense for your home.
You don’t necessarily need to filter every litre of water entering the property.
Sometimes the better solution is simply to filter the water you actually drink.
Frequently Asked Questions
Is an under-sink water filter worth it?
An under-sink water filter can be worthwhile if you mainly want to improve the taste and odour of the water you drink and cook with. Because it filters water at the kitchen rather than treating every litre entering the home, it can be a practical alternative to a whole-house filtration system.
Does an under-sink water filter remove chlorine?
Many under-sink systems use activated carbon filtration, which can reduce chlorine taste and odour. The exact performance depends on the cartridge and filtration system, so homeowners should check what contaminants or substances the particular filter is designed and certified to reduce.
What is the difference between an under-sink filter and a whole-house water filter?
An under-sink filter treats water at a specific point of use, usually the kitchen drinking-water tap. A whole-house filtration system treats water before it is distributed throughout the property, including bathrooms, laundry and other outlets. If the main objective is better drinking water, an under-sink system may be sufficient.
Is reverse osmosis better than a carbon water filter?
Reverse osmosis and carbon filtration perform different jobs. Carbon filters are commonly used to improve taste and reduce chlorine and odours, while reverse osmosis can remove a broader range of dissolved substances. Reverse-osmosis systems are generally more complex and require additional maintenance, so the best option depends on what the homeowner wants to remove from the water.
Do I need a separate tap for an under-sink water filter?
Not necessarily. An under-sink water filter can supply a dedicated drinking-water tap, or it can be connected to a suitable three-way mixer that provides normal hot water, normal cold water and filtered drinking water through one tap assembly.
How often should under-sink water filter cartridges be changed?
Replacement intervals vary depending on the filter manufacturer, cartridge type, household water consumption and local water conditions. Filter cartridges should be replaced according to the manufacturer's instructions rather than being left in service indefinitely.
Can a plumber install an under-sink water filter?
Yes. A plumber can install an appropriate under-sink filtration system, connect the water supply and fit a dedicated drinking-water tap or compatible mixer. Plumbing products used in the installation should be suitable for Australian drinking-water applications.
Do I need a whole-house water filtration system?
Not every household needs whole-house filtration. If the main concern is improving drinking and cooking water, an under-sink point-of-use filter may provide a simpler solution. Whole-house filtration is more appropriate when there is a reason to treat water supplied throughout the entire property.
