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What is an under-sink water filter?
An under-sink water filter is a mains-fed system installed inside the cupboard beneath your kitchen, scullery or laundry sink.
Mains water passes through one or more filter cartridges before reaching the tap, reducing chlorine and chlorine by-products, organic chemicals that affect the taste and smell, sediment such as sand, grit and fine particles, and improving the overall clarity and taste of drinking water.
In Western Australia, where mains water runs hard and is chlorine-heavy, an under sink water filter is the most common entry point to filtered drinking water.
Perth mains water meets the Australian Drinking Water Guidelines (NHMRC), but it still contains chlorine used for disinfection, naturally occurring minerals such as calcium and magnesium and trace sediment from the distribution network which is why most households notice scale and a stronger taste at the tap.
If you have moved from Melbourne or the east coast, the water feels different. You are not imagining it. Most homeowners notice the same things. Scale on the kettle. A strong chlorine taste from the tap. Dry skin after a shower.
An under-sink water filter is a practical starting point. It connects to your mains water supply, sits under the bench, and gives you filtered drinking water on demand.
For most households, that is enough to make the kitchen tap the first choice again.
How does an under-sink water filter work?
If you are comparing under-sink water filter options, start with the basics.
Domestic under-sink filter systems connect to the cold water supply and Twin Filter systems usually come with a small, dedicated filtered water tap which is fixed to the sink or benchtop next to your existing kitchen taps.
If you want to keep your existing kitchen mixer tap as part of your overall kitchen design, the Mixerflow filter system can feed filtered water through this directly.
With both systems, filtered water is there when you turn on the tap. No jug to fill, and no bottled water to keep taking up fridge space.
We offer free standard installation on domestic water filter systems across most parts of Perth and regional Western Australia.
We usually ask for photos of the under-sink area and benchtop to check suitability and will confirm your eligibility for free installation at the time of purchase.
What does an under-sink filter remove, and what does it not?
A standard twin or single under-sink water filter system uses a combination of sediment and carbon filtration to treat drinking water at the kitchen tap.
In practical terms, this means it is designed to reduce:
- Chlorine used for disinfection which affects taste and odour
- Sediment such as sand, grit and fine particles
- Chlorine by-products and organic compounds that affect taste and smell
- Cloudiness and visible impurities in drinking water.
By removing sediment and organic materials that bacteria can attach to, most households notice an immediate improvement in the taste and smell of their water once an under sink water filter has been installed.
What a standard under sink filter systems does not do is remove the calcium and magnesium that cause hard water scale.
That white residue on your kettle and shower screen is a mineral issue.
It requires either specialised scale-reduction under sink filters or a water softener to improve water throughout the home.
This is the most common mistake homeowners make when buying a filter system online.
For PFAS (industrial “forever” chemicals), fluoride and other dissolved chemicals, reverse osmosis provides a deeper level of filtration.
A 2019 investigation by the WA Department of Water and Environmental Regulation detected PFAS in 91% of groundwater sampling locations across the Perth metropolitan area. Municipal mains water remains compliant but bore water carries more risk.
An under-sink filter handles drinking and cooking water at the kitchen tap. If scale is building up across bathroom taps, shower screens, and appliances, that is a separate issue.
How do under-sink filters compare to other systems?
Different filtration systems solve different water issues. The right starting point depends on what you’re noticing in your home.
| Filter type | What it addresses | Setup | Typical cost | Best for |
| Under-Sink Water Filter Systems (Twin and Single Filter) | Removes chlorine taste, sediment and chemicals in kitchen tap water for drinking, cooking, and washing up.
Scale-reduction options available – does not soften water |
Plumbed in under sink | From $500 | Most WA homes on municipal mains water |
| Reverse Osmosis (under sink) | All of the above and reduces PFAS, heavy metals, fluoride, calcium & dissolved solids | Plumbed in under sink | From $650 | Highest level of purification & contamination removal, good for treating bore water |
| Whole-House Filter and Softener | Reduces chlorine taste, sediment, and contaminants, and removes calcium through softening | Connected to mains water outside property | From $2,500 | Softer, cleaner water from every tap, shower, and appliance in the property |
| Jug filter | Reduces chlorine taste, removes some sediment, and offers limited scale reduction (depending on model) | Benchtop jug | $30-$80 for jugs $80-$150 p.a. for cartridges | Renters, light use and where access to plumbing is restricted |
| Bottled water | Drinking water only | Purchased and stored | $500-$1,000 per person, p.a. | Portable and home use |
Is an under-sink filter worth it for your home?
Most people don’t begin by asking for a specific filter. They start with a problem. The water tastes weird. The jug is always empty. The family is spending too much on bottled water.
For most homes in WA, a mains-fed under-sink water filter system is a reliable, convenient, and cost-effective solution.
Filtered water is there when you turn on the tap and never runs out.
It saves bench and fridge space and removes the daily hassle and cost of buying and carrying bottled water.
Water filter cartridges need replacing every 6 to 12 months, depending on how much water you use and the quality of water coming into your home.
Regular filter replacement is vital to protect the quality of your drinking water. We’ll send a reminder when yours is due, then handle the servicing and cartridge replacement for you.
Which under-sink system suits your home?
We’re always happy to provide free, unbiased advice based on the quality of your source water, benchtop setup and what you want the filter to improve.
Our Twin Filter System is a two-stage sediment and carbon filtration system. It suits Perth metro homes on mains water and is the most common recommendation we make.
Our Mixerflow Filter System delivers filtered water through your existing mixer tap and the single filter system takes up less space under the sink.
Water2water is privately owned and we’re not tied to any manufacturers. We will never recommend something your home does not need.
We recommend the right product for the right need. If you want to learn more about different types of water filters, our article on water filtration for your home explains everything we install and service.
Browse our full under-sink filter range to compare the main kitchen tap options.
Frequently asked questions
No. A standard two-stage twin under-sink filter does not remove fluoride. Fluoride is a dissolved mineral and passes through carbon and sediment cartridges. If fluoride removal matters to you, a reverse osmosis system is the right call.
Every 6 to 12 months, depending on household size and water source. Larger households and homes fed with treated bore water will need to replace filters more often than a single person household on municipal mains water. We’ll send a reminder when yours is due.
An under-sink filter handles drinking and cooking water at the kitchen tap. A whole-house system filters all the water entering your home. The whole-house filter system and water softener option is the right choice when hard water scale buildup, drinking and shower water quality and chlorine taste and odour affects your whole home.
No – Hard water comes from calcium and magnesium, which a standard under-sink filter does not remove. Scale reduction filters can help manage scale by breaking down calcium, but they do not soften water. Only a dedicated water softener removes hardness.
Not sure which water filter system is right for your home?
Call us on 1300 880 303. We answer all calls in person. No automated systems, no buttons to press.