whole house water filter vs under sink
Whole House Water Filter vs Under Sink: Which Is Right for Your Melbourne Home? (2026 Guide)
Whole-house water filter vs. under-sink, which one does your Melbourne home actually need? Compare coverage, cost, filtration level & find out when you need both. Free quote available.
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One of the most common questions we get from Melbourne homeowners is: “Should I get a whole-house water filter, or is an under-sink system enough?” Some people ask us about both in the same enquiry, wanting full house filtration and a separate drinking water system, but not sure if that’s necessary or overkill.
The truth is, these are two different systems that solve two different problems. A whole-house water filter treats every drop of water entering your home. An under-sink reverse osmosis (RO) system provides ultra-purified drinking water at your kitchen tap. Some Melbourne homes need one, some need the other, and some genuinely benefit from both.
In this guide, we’ll break down exactly what each system does, what it costs, and help you figure out which setup is right for your home and budget.
The Key Difference: Point of Entry vs Point of Use
Before comparing features, it helps to understand the fundamental difference between these two types of systems:
A whole-house water filter is a point-of-entry (POE) system. It’s installed where your main water line enters your property before the water reaches any tap, shower, or appliance. This means every outlet in your home gets filtered water: kitchen, bathrooms, laundry, garden tap, hot water system, dishwasher, and washing machine.
An under-sink water filter is a point-of-use (POU) system. It’s installed beneath your kitchen sink and only filters the water that comes out of that specific tap. Installed by licensed plumbers, these systems connect directly into your existing plumbing for safe and compliant operation. In Melbourne, the most effective under-sink option is a reverse osmosis (RO) system, which pushes water through a semi-permeable membrane to remove up to 98% of dissolved contaminants. A professional plumbing service can also ensure the correct pressure regulation and drainage setup required for optimal RO performance.
Think of it this way: a whole-house filter gives your entire home a good level of filtration, while an under-sink RO system gives your kitchen tap an exceptional level of purification. They work at different scales and different levels of intensity.
Side-by-Side Comparison: Whole House vs Under Sink Water Filter
Here’s a clear comparison to help you see the differences at a glance:
Feature | Whole House Filter (HP3) | Under Sink RO System |
How It Works | Filters all water at the main entry point before it reaches any tap | Purifies water at the kitchen tap using reverse osmosis membrane technology |
Coverage | Every tap, shower, and appliance in the home | Kitchen tap only (drinking and cooking) |
Filtration Level | 3-stage: removes sediment, chlorine, chloramine, herbicides, pesticides, heavy metals, VOCs (down to 0.5 micron) | 7-stage: removes everything above PLUS dissolved solids, fluoride, and bacteria (down to 0.0001 micron) |
Best For | Families, homeowners, and anyone wanting filtered water throughout the entire house | Health-conscious households wanting the purest possible drinking water |
Installed Price | From $1,100 inc. GST | From $1,100 inc. GST |
Filter Replacement | $350 every 12–18 months (DIY) | Membrane + cartridges replaced periodically |
Installation | Licensed plumber required to install at the main water line | Licensed plumber required to install under the kitchen sink with a dedicated tap |
Protects Appliances? | Yes, hot water system, washing machine, dishwasher | No, kitchen tap only |
Removes Chlorine from Showers? | Yes | No |
Suitable for Apartments? | Usually does not require access to the main water line | Yes installs under the kitchen sink in any property |
As you can see, these systems aren’t competing because they’re complementary. One handles breadth (every tap), the other handles depth (maximum purity at one tap).
When a Whole House Water Filter Is the Right Choice
A whole-house water filter is the right fit for your Melbourne home if:
- You want filtered water from every tap in the kitchen, bathroom, laundry, and garden
- You’re noticing chlorine taste or smell across your home in drinking water, showers, and when cooking
- You want to protect your plumbing and appliances from sediment, scale buildup, and chemical damage
- You or your family experience dry skin, hair irritation, or eczema that may be aggravated by chlorine in shower water
- You live in an area with older pipes (common in suburbs like Coburg, Essendon, Moonee Ponds, and Preston), where sediment and trace metals can enter the water supply
- Your renovation or building installation is easier and cheaper when plumbing is already being worked on
At Select Plumbing and Gas, we install the HP3 3-Stage Whole House Filtration System, built with 304 brushed stainless steel, designed for Melbourne’s water conditions, and fully installed for $1,100 including GST.
Under-Sink Reverse Osmosis System vs Whole House Filter: When It’s the Right Choice
An under-sink RO system is ideal if:
- Your primary concern is the purity of your drinking and cooking water
- You want to remove dissolved contaminants that standard carbon filters can’t catch, such as fluoride, dissolved solids, and bacteria
- You live in an apartment or rental property where you can’t access the main water line for a whole-house system
- You’re a health-conscious household that wants the highest level of water purification available for consumption
- You want to stop buying bottled water and get better-than-bottled quality directly from your kitchen tap
Our 7-Stage High Alkaline Reverse Osmosis System removes up to 98% of common tap water contaminants and adds back magnesium and potassium electrolytes for improved hydration. It’s fully installed for $1,100 including GST, with a dedicated chrome tap at your kitchen sink.
Want Help Deciding? Get a Free Assessment Tell us about your property, your water concerns, and your budget. We’ll recommend the right system (or combination) for your Melbourne home and give you a clear, upfront price. |
When You Need Both Systems: Why Many Melbourne Homeowners Choose This
Here’s something most comparison articles won’t tell you: for many Melbourne households, the best setup is actually both systems working together.
Here’s why that combination makes sense:
A whole-house filter removes chlorine, sediment, and chemicals from all the water in your home. This protects your skin in the shower, extends the life of your appliances, and eliminates that chlorine taste from every tap. But it filters water at a flow rate of around 40 litres per minute, which means it uses larger micron filtration (down to 0.5 micron), effective, but not as fine as what you’d want for drinking water.
An under-sink RO system slows the water down to around 3 litres per minute and pushes it through a membrane at 0.0001 micron, removing virtually everything, including dissolved solids, fluoride, and trace pharmaceuticals. This gives you bottled-quality water (or better) straight from your kitchen tap.
- Whole home protection — filtered water for showers, baths, laundry, and appliances
- Ultra-pure drinking water — 7-stage purification at the kitchen tap for drinking and cooking
- Maximum appliance protection — the whole house filter catches sediment before it reaches your hot water system and appliances
- Complete peace of mind — every tap in your home is covered, with your drinking water receiving the highest level of purification available
This is the setup we recommend for families in Melbourne’s growth corridors, suburbs like Tarneit, Werribee, Point Cook, and Truganina, where water travels long distances through the Greater Western Water network and picks up higher levels of chloramine and sediment along the way.
Cost Comparison: What Each Option Costs in Melbourne
| Setup | Installed Price | Annual Maintenance | Best For |
| Whole House Filter Only | From $1,100 | ~$350/year | Families, homeowners, renovators |
| Under Sink RO Only | From $1,100 | ~$150–$250/year | Apartments, renters, health-focused |
| Both Systems Combined | From $2,200 | ~$500–$600/year | Maximum protection, families in western/outer suburbs |
We offer 0% interest finance on all water filtration systems, so whether you choose one system or both, you can spread the cost across manageable payments without any interest charges.
Which System Do Most Melbourne Homeowners Choose?
Based on the enquiries we receive, the majority of Melbourne homeowners come to us asking about whole-house filtration. The most common request we see is for a system that gives filtered water to the entire home, every shower, every tap, every appliance.
This makes sense for most standalone Melbourne homes, because the main concerns driving people to search for filtration are:
- Chlorine taste and smell across all taps (not just the kitchen)
- Skin and hair issues from showering in chlorinated water
- Protecting expensive appliances like hot water systems and dishwashers from sediment and chemical buildup
- Wanting to stop relying on bottled water for the household
For apartment owners and renters who can’t modify the main water line, the under-sink RO system is the clear winner. It delivers exceptional drinking water quality without needing access to the building’s shared plumbing.
And for homeowners who want the absolute best water quality in their home, especially in Melbourne’s western suburbs where chloramine levels tend to be higher, we recommend the dual system approach: whole house filtration plus under-sink RO.
Quick Decision Guide: Which Setup Is Right for You?
Your Situation | We Recommend |
You own a house and want filtered water everywhere | → Whole House Filter (HP3) |
You live in an apartment or a rental | → Under Sink RO System |
You want the purest drinking water possible | → Under Sink RO System |
You’re concerned about chlorine in showers and baths | → Whole House Filter (HP3) |
You want to protect your appliances from sediment and scale | → Whole House Filter (HP3) |
You’re renovating or building a new home | → Both Systems (ideal timing) |
You’re in Melbourne’s western suburbs (Tarneit, Werribee, Point Cook) | → Both Systems (higher chloramine levels) |
You have a family with young children | → Both Systems (maximum protection) |
Budget is the main concern right now | → Start with one, add the other later |
Not sure where you fit? That’s exactly what our free assessment is for. We’ll look at your property, your water supply area, and your household needs, then recommend the setup that makes the most sense for your situation and budget.
Frequently Asked Questions About Water Filter Costs in Melbourne
Can I start with one system and add the other later?
Absolutely. Many of our Melbourne customers start with a whole-house filter and add an under-sink RO system later (or vice versa). The systems are completely independent, so adding a second system down the track is straightforward.
Is the whole-house filter enough for drinking water, or do I need the RO too?
For most Melbourne households, a whole-house filter delivers great-tasting, clean drinking water that’s a significant upgrade from unfiltered tap water. The HP3 system filters down to 0.5 micron and removes chlorine, chloramine, and heavy metals. However, if you want the highest possible purity for drinking and cooking, including removal of dissolved solids and fluoride, an under-sink RO system takes it to another level.
Do I need a plumber to install either system?
Yes. In Victoria, both whole-house and under-sink water filter systems must be installed by a licensed plumber to comply with Australian plumbing standards. At Select Plumbing and Gas, installation is included in our pricing, and you’re not paying a separate installer on top of the system cost.
I’m in an apartment. Can I get a whole-house filter?
In most cases, no. Apartments share a main water line controlled by the body corporate, so installing a whole-house filter isn’t practical. The under-sink RO system is the ideal solution for apartments. It installs under your kitchen sink, provides exceptional drinking water quality, and doesn’t require access to shared plumbing.
Will a whole-house filter affect my water pressure?
No. The HP3 system is designed to maintain normal household water pressure. We test every tap in your home after installation to confirm proper flow and pressure. Melbourne’s mains water pressure is well within the range our system handles without noticeable flow reduction.
Which system is better if I’m worried about Melbourne’s water quality in the western suburbs?
Melbourne’s western suburbs (serviced by Greater Western Water) use chloramine rather than chlorine as a disinfectant. Chloramine is harder to remove with standard carbon filters. Our HP3 whole-house system includes a 0.5 micron composite carbon block specifically designed for chloramine reduction. If you’re in Tarneit, Werribee, Point Cook, Truganina, or Melton, we’d recommend the whole-house filter as a minimum, with the under-sink RO for maximum protection.
Get the Right System for Your Melbourne Home
