Do You Need a Whole House Water Filter AND a Water Softener?

A whole house water filter and a water softener are often confused — but they do completely different things. Here’s a clear explanation of when you need one, the other, or both.

See our full guide: Whole House Water Filter & Softener Systems and browse our whole house filter range.

What Does a Whole House Water Filter Do?

A whole house filter removes contaminants and impurities from your water at the point where the main supply enters your home. Depending on the filter stages, it removes chlorine, chloramines, sediment, heavy metals, VOCs, and taste/odour compounds. Every tap, shower, and appliance in the house receives filtered water.

What it doesn’t do: remove hardness minerals (calcium and magnesium). A standard carbon/sediment filter won’t soften your water.

What Does a Water Softener Do?

A water softener uses ion exchange to remove calcium and magnesium — the minerals that cause hard water scale. Hard water ions are swapped for sodium ions as water passes through the softener resin. The result is “softened” water that doesn’t form scale on pipes, appliances, and fixtures.

What it doesn’t do: remove chlorine, bacteria, heavy metals, or chemical contaminants. A water softener is not a water filter.

Do You Need Both?

If your water is hard and contains chlorine or other contaminants — which is common in many Australian town water supplies — then yes, both are beneficial. A filter alone won’t address scale buildup. A softener alone won’t remove chlorine or chemical contaminants.

The ideal setup combines both in sequence:

1. Sediment pre-filter — protects the softener resin from fouling
2. Water softener — removes hardness minerals
3. Carbon filter — removes chlorine (chlorine degrades softener resin over time, so it should come after the softener)

Salt-Free Alternatives

If you don’t want to use a salt-based softener, a salt-free scale conditioner is an alternative. It doesn’t remove hardness minerals but changes their structure so they don’t form scale. Benefits: no salt, no sodium added to water, lower maintenance, better for gardens and drinking water. Limitation: doesn’t provide the same skin/hair softening benefits as true ion exchange softening.

Frequently Asked Questions