Why Your Whole House Filter Is Not Fixing Hard Water

Why whole house filters aren’t enough for hard water

A whole house water filter improves water quality by reducing chlorine taste, odour, sediment and other contaminants throughout the home. What it may not do is address hard water scale.

Perth water is naturally hard, and many households notice the effects on taps, shower screens, kettles and appliances. If your water tastes better after installing a whole-house filter but scale keeps returning, the system has not failed. It may simply not include any scale reduction or softening technology.

Understanding the difference between filtration, scale reduction and softening is often the key to choosing the right system.

What a whole house water filter does

A whole house water filter system treats mains water before it enters your home. Every tap, shower, toilet, laundry outlet and appliance receives filtered water from the same supply.

Perth mains water is disinfected with chlorine before it reaches your home. While the water remains safe to drink, many households notice the taste and odour chlorine can leave behind. 

A whole house filter helps reduce this across every outlet in the home and most systems use a combination of sediment and carbon filtration.

A sediment filter removes particles such as sand, rust and fine grit that can enter the water supply through the distribution network. A carbon filter reduces chlorine, chlorine by-products and other contaminants that affect the taste and smell of water.

Some whole house filtration systems also include scale reduction media designed to help reduce scale buildup.  These systems can be an effective option for households who want to reduce the effects of hard water without installing a separate water softening system.

Whole house systems vary far more than many homeowners realise when they first start comparing options.

Our whole house filters and water softeners range covers the systems we install and service across WA.

Perth water runs hard

Perth’s water hardness comes from the way much of the city’s water is sourced.

The Gnangara Groundwater System is Perth’s largest natural source of drinking water. As water moves through underground layers of limestone and sandstone known as aquifers (natural formations that store and carry groundwater), minerals such as calcium and magnesium dissolve into the water.

Perth’s reliance on groundwater from mineral-rich aquifers is one of the main reasons Perth’s water is harder than in most east-coast cities, which tend to rely more heavily on surface water catchments.

WaterScore reports Perth water hardness levels ranging from around 29 mg/L in some southern areas to more than 200 mg/L in parts of Perth’s northern suburbs. Two Rocks (228 mg/L) and Yanchep (204 mg/L) consistently rank among the hardest water supplies in the Perth metropolitan area.

People moving from Melbourne or the east coast often notice the difference quickly. Scale appears on kettles, taps and shower screens far sooner than they are used to.

In the Pilbara, including Karratha, Tom Price and Paraburdoo, mineral levels are often higher again. Water filtration systems work harder, scale builds faster and filter cartridges need changing more frequently than in many Perth metro homes.

Perth hard water is a topic in its own right. Our hard water overview explains what causes it and how Perth homes treat it.

Why scale keeps returning after whole-house filtration

This is one of the most common whole house filter questions our technicians hear in Perth homes.

Many homeowners hear the term whole house filtration and assume it means every water issue is being filtered out and treated. In reality, water quality and hard water scale are often two separate problems that require different types of treatment.

A sediment filter is designed to remove dirt, rust, sand, and other fine particles. A carbon filter is designed to reduce chlorine, chlorine by-products, contaminants and improve taste and odour.

Calcium and magnesium behave differently. They are dissolved minerals rather than particles, so they pass through standard sediment and carbon filters largely unchanged.

That’s why many homes experiencing hard water scale choose a filtration system with scale-reduction technology or a water softener. Scale-reduction filters help reduce scale buildup but they don’t soften water in the same way as a dedicated water softener.

If scale keeps returning after installing a whole house filter, it may simply mean the system was designed to improve water quality rather than address hardness.

The filter has not failed. It was designed for a different job.

The right system for hard water scale

When scale is the main concern, there are two common approaches.

• Scale-reduction filtration: A scale-reduction filter can be added to an under-sink or whole-house filtration system. It changes how hardness minerals behave in the water, helping to reduce scale buildup without removing the minerals. This can be an effective option where scale is moderate.
• Water softening: A water softener provides the highest level of hardness treatment for the entire home. It reduces the calcium and magnesium responsible for scale before the water reaches your taps, showers and appliances, using ion exchange to replace the hardness minerals with a small amount of sodium.

Scale builds up more slowly on shower screens, taps and tiles. Kettles, dishwashers, washing machines and coffee machines collect less mineral buildup. Soap lathers more easily and water feels noticeably different on skin and hair.

Although softening reduces magnesium as part of the process, magnesium is a naturally occurring mineral and part of a normal, healthy diet. 

For households that want to retain the benefits of magnesium in their drinking water, a remineralising filter can be installed at the kitchen tap to reintroduce beneficial minerals after treatment.

If your priority is reducing scale buildup in the kettle or coffee machine, rather than across the entire property, our Maxiflow Scale Reduction system is a targeted option.

Where scale affects taps, showers and appliances across the home, our Perth water softener overview covers how softeners work and what to expect after installation.

When your home needs filtration and softening

For many Perth homes, combining a filtration system with a water softener provides the best overall result. 

Water quality concerns and hard water scale are often separate issues. Filtration systems improve water quality by reducing chlorine, sediment and contaminants, while scale reduction systems and water softeners help manage the effects of hard water.

A standard whole-house or under-sink water filter system improves the taste, smell and overall quality of water by reducing chlorine, sediment and other contaminants.

Where scale is also a concern, scale-reduction filters can be added to either system to help limit buildup while continuing to improve water quality through filtration.

For the most complete result, a water filter system can be paired with a dedicated water softener. This is what we mean by genuine complete home filtration: a solution that improves water quality and treats the effects of hard water throughout the home.

Water2water has been helping households in Perth, Karratha, across the Pilbara and regional WA to choose the best water filtration for your home for more than 25 years.

We install, service, repair and rent all makes and model of filter systems, water coolers and drinking water dispensers and have a large servicing team living and working across WA.