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Whole-home filtration vs under-sink filters — what's the difference?

First Class Filtration June 2026 6 min read

When people start looking into water filtration, they usually discover two very different categories: point-of-use filters (under-sink units, jug filters, tap attachments) and point-of-entry systems (whole-home filtration installed on your main water line). They sound similar. They do very different jobs.

Under-sink filters: one tap, treated well

An under-sink filter sits in the cupboard below your kitchen sink and treats the water going to that single tap. A good one will noticeably improve the taste and smell of your drinking water, and for renters or apartment dwellers it's often the only practical option.

The limitation is in the name: it filters one tap. Everything else in your home — the shower, the bath, the laundry, the dishwasher, the hot water service, the garden tap — still receives completely untreated mains water.

That matters more than most people realise, because chlorine and chloramine don't only affect the water you drink:

  • In the shower, warm chlorinated water strips natural oils from skin and hair — a common contributor to dryness, irritation, and dull, brittle hair, especially for sensitive skin.
  • In your appliances, chlorine degrades rubber seals, gaskets, and flappers over time, while sediment and scale build up inside water heaters, dishwashers, and washing machines, shortening their lifespan.
  • In the rest of the kitchen, you're still rinsing fruit and vegetables, making ice, and filling pots from unfiltered taps.

Whole-home filtration: every litre, every tap

A whole-home (inline) system is installed on the main water line where it enters your property. Every litre of water your household uses passes through it first — so every tap, shower, and appliance gets the same filtered water.

Our FCF system does this in two stages. A stepped sediment filter grades from 25 microns down to 5 microns, capturing dirt, rust, and particulate before it enters your plumbing. A 1-micron carbon ChloraGuard stage then targets chemicals — including the chloramine that's heavily relied on in Adelaide's network and that standard carbon filters struggle with. The housings are heavy-duty, weather- and UV-rated, and the whole unit is wrapped in a 2 mm 316 stainless steel cover, powder-coated to match your home.

Side by side

FactorWhole-home (FCF)Under-sink
CoverageEvery tap, shower & applianceOne tap only
Drinking water taste✓ Yes✓ Yes
Showers — skin & hair✓ Yes✗ No
Protects appliances & hot water service✓ Yes✗ No
Sediment removed before your plumbing✓ Yes✗ No
InstallationProfessional, outdoors on main lineDIY or plumber, in cupboard
MaintenanceScheduled filter changes via the FCF appCartridge changes, owner-managed
Upfront costHigher — one system for the whole houseLower — per tap
A note on flow rate

A common worry with whole-home systems is losing water pressure. Filter quality is what decides this — our system uses high-flow filter media specifically selected for minimal pressure drop, so showers and taps perform the way they should.

Which one is right for you?

If your only goal is better-tasting drinking water at the kitchen sink — and especially if you rent — an under-sink unit is a sensible, affordable choice.

If you own your home and you're thinking about water quality more broadly — your family's showers, your skin and hair, your appliances, your plumbing — a whole-home system addresses all of it with a single installation. One system, professionally installed and maintained, instead of a patchwork of point filters that still leaves most of your water untreated.

Not sure which camp you're in? That's exactly what our free, no-obligation water assessment is for.

Sources & further reading

Aquasana — Whole house vs under-sink water filters

Kind Water Systems — Whole house vs under sink filter

Culligan — Under-sink filter, whole house filtration or softening?

WaterScore — Chlorine in Australian tap water

This article is general information for homeowners, not health advice. Adelaide's mains water meets the Australian Drinking Water Guidelines and is safe to drink.

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