Quick answer
A whole-house filter improves water at every tap by removing sediment, chlorine, tastes and odours. Reverse osmosis is an under-sink system that removes most dissolved solids, including fluoride, from drinking water. A water softener swaps out hardness minerals to stop scale. Many homes combine a whole-house filter with reverse osmosis at the kitchen sink.
Side by side
| Whole-house filter | Reverse osmosis | Water softener | |
|---|---|---|---|
| Main job | Sediment, chlorine, taste, odour | Most dissolved solids | Hardness minerals |
| Where | At the water meter | Under the kitchen sink | At the water meter |
| Covers | Every tap | One tap | Every tap |
| Fluoride | Generally not removed | Largely removed | Not removed |
| Upkeep | Cartridge changes | Cartridges and membrane | Salt top-ups and regeneration |
Reverse osmosis
Reverse osmosis pushes water through a very fine membrane that removes most dissolved solids, including fluoride and many minerals. It’s usually installed under the kitchen sink because it’s slower and sends some water to the drain while it works. Some systems add minerals back afterwards for taste.
Water softeners
A softener uses ion exchange to replace calcium and magnesium, the minerals that cause hard water and scale. It needs salt and regenerates itself regularly. Melbourne’s water is generally soft, so softeners are less common there than in hard-water areas.
Limescale-reduction media isn’t a softener
Some whole-house filters include limescale-reduction media. These make scale less likely to build up, but they don’t remove hardness minerals the way a softener does.
Which do you need?
- Chlorine taste, shower smell, sediment: a whole-house filter.
- Drinking water with as little dissolved content as possible: reverse osmosis.
- Heavy scale from genuinely hard water: a softener.
Common questions
Do I need reverse osmosis if I have a whole-house filter?
Only if you want to remove dissolved solids such as fluoride from your drinking water. A whole-house filter handles sediment, chlorine, taste and odour at every tap.
Is a limescale filter the same as a water softener?
No. Limescale-reduction media reduce scale build-up; a softener removes hardness minerals through ion exchange.
Does reverse osmosis waste water?
Reverse osmosis sends some water to the drain as it filters. How much depends on the system and your water pressure.
General information for homes on town water in Victoria. It isn’t a substitute for advice about your specific property or water supply.
