Your ultimate guide to choosing the right water filter

What Should I Consider Before Buying a Water Filter?

Every year, we help thousands of Australians to purify their water. To help our customers find the right water filter, we guide them through a sequence of simple steps to help find a filter system specifically suited to their needs. In this post, we’ll share that exact process. By determining your water supply type, you can decide what to filter out of your water, and then explore the best filter options.

1.   Understand where your tap water comes from

2.   Decide what to filter out of your water

3.   Familiarise yourself with common filtration methods

4.   Work out what size filter system you need

5.   Factor in the cost of installation and maintenance

Where does my tap water come from?

The first step to finding the right filter is to understand where your tap water comes from.  

Mains water (also known as municipal or town water) is supplied to most residential neighbourhoods. If you have a mains water supply, your local council will have treated the water (originally from a dam, river, or aquifer) to remove many of the contaminants. They will have also added disinfection chemicals which are great for stopping bacteria growing in the pipework but are usually not great for your health.

Popular: Aquastream 20" Whole House Filter System for Mains Water (Great for sediment & chlorine reduction)

Rain water tanks are commonly used in both rural and residential areas to collect the water from the roofs of buildings and houses. It’s well worth finding out whether your water supply is a combination of mains water and rainwater. It’s common in towns and cities to use rainwater when available, and to switch to a mains water supply if the rainwater tank runs dry. If this is the case at your home, use the table below to look at the contaminants commonly found in both types of water supply so you can decide which ones to filter out.

Popular: Aquastream H2O-PRO Dual UV Water Treatment System (Great for sediment reduction & microbial disinfection)

Bore water (also known as well or ground water) is commonly used on rural properties. The quality of bore water tends to vary depending on the location, the type of soil/rock, the frequency of rain and whether pesticides and herbicides are used nearby. We often see elevated levels of scale and metals in bore water. If you have the choice between using rainwater and bore water, we recommend using your rainwater as it tends to be cleaner to start with which makes it easier to purify. The below table contains a list of common bore water contaminants and is by no means an exhaustive list. When treating bore water to make it fit for consumption we recommend taking samples of the water to a laboratory that conducts bacteriological and chemical tests. Check that they provide a report on whether the level of each contaminant is safe, so you know which ones need improving. 

What should I filter out of my water?

The answer to this question depends on the type of water and your personal preferences. Here’s a general guide to what we recommend filtering out of your water.

·         For mains water, filtering out chlorine provides an impressive improvement in the taste of the water while improving the health of your skin and hair.

·         For rainwater, filtering out dirt & sand is the most visible improvement, and removal of bacteria & cysts provides the greatest improvement in gut health.

·         For bore water, filtering out clay, sand, iron and scale are common ways to improve water quality. Due to the varied nature of bore water, we recommend getting your water tested to determine what contaminants may be present. You can then choose a filter system that specifically targets them.

The human body is remarkable in the way it can deal with many microbiological and chemical contaminants. Water supplies often contain a large variety of contaminants. It’s a question of which ones you feel are impacting your health. We recommend making a list of what you want to filter out, and whether you want to retain anything (e.g. minerals or fluoride). This will save you time when comparing your filter system options. Ultimately, the decision of what to filter out of your water is up to you and what you feel is important for your health and well-being.

Contaminants found in different types of water:

Mains Water

(AKA municipal or town water)


(pic of tank & rain)

Bore Water

(picture or diagram of bore)

Commonly Found

·         Chlorine

·         Chloramines

·         Scale

·         Giardia

·         Cryptosporidium

·         Fluoride

·         Bad taste & Odour

·         Dirt

·         Rust

·         Sand

·         Microplastics

·         E. coli

·         Giardia

·         Cryptosporidium

·         Lead

·         Dirt

·         Rust

·         Sand

·         Pesticides

·         Herbicides


·         Scale

·         Heavy Metals

·         E. coli

·         Giardia

·         Cryptosporidium

·         Pesticides

·         Herbicides

·         Iron

·         Arsenic

·         Dirt

·         Rust

·         Sand

·         Clay

·         Bad taste & Odour


Rarely Found

· Residual medicines

· VOCs

· Arsenic


· Mercury

· VOCs

· Bad taste & Odour




What are the best methods of filtration?

Water filtration technology has been designed for filtering out almost anything you want. Water contaminants are best classified into 4 broad categories: Microbial, Chemical, Sediment and Scale. Here, we’ll explain the best methods of filtration for each category.


Giardia, cryptosporidium, E. coli, and other bacteria (commonly known as bugs) fall into this category.

UV disinfection systems are exceptional at deactivating or killing microbes. They’re used extensively across Australia providing reliable, chemical-free disinfection. They’re also cost effective when treating high volumes of water. A prefilter with a pore size of 5 microns or less is required for the UV system to work properly. If you’re looking to remove microbes from your whole-house water supply, UV disinfection is one of the best options.

Microfiltration systems are sometimes a good choice when filtering smaller quantities of water (e.g. drinking water only systems). As water passes through the microscopic pores in the filter, bacteria is trapped which plugs up the filter pores, slowly decreasing the flow rate. The speed that the filter blocks is dependent on the level of contaminants in your water so be sure to check the estimated life of the filter cartridges, and factor in cartridge replacement costs. We recommend choosing a system that has a double O-ring seal design to stop untreated water bypassing the filter.

Water sanitiser is commonly used where it’s impractical to install a UV system such as in remote areas without access to electricity. We recommend choosing a water sanitiser that doesn’t create dangerous by-products like THMs.


Chlorine, fluoride, chloramines bad taste and odours are classed in this category.

Activated carbon filters are exceptional at reducing chlorine, bad taste & odour, many pesticides, herbicides, and VOCs. They’re popular due to their simplicity and low cost. Some carbon filters contain a special blend of filtration media to target specific contaminants such as lead or chloramines. When filtering rainwater, we recommend choosing a Silver-Carbon cartridge which inhibits the growth of bacteria in the carbon media. Activated carbon filters don’t filter out fluoride, sodium, minerals, and some heavy metals such as aluminium. For removal of these contaminants, you may want to consider a reverse osmosis system.

Reverse Osmosis (RO) filtration systems offer remarkable removal rates for almost all chemicals and heavy metals including barium, cadmium, chromium, fluoride, PFAS, radium, pesticides, herbicides, aluminium and lead.  They do this by utilising an ultra-fine filter membrane with a pore size of around 0.0005 microns. That’s smaller than one millionth of a millimetre! Around 80% of the feed water is used to keep the RO membrane clean and then flows to the drain, while around 20% ends up as pure water. For an average household, this equates to less than 50L per day going to drain; the same amount of water that is used in the manufacturing process of 10 disposable plastic bottles.  RO typically reduces the mineral content of mains water to around 10-20 ppm, a similar level to rainwater. Most of our customers notice their water tastes much better after installing an RO system. The better taste is a result of the lack of toxic chemicals, organics, and high mineral content. Remineralising cartridges can be added if you feel that the minerals are beneficial for your health. Reverse osmosis isn’t suited for treating rainwater as the membrane is easily fouled by microbial contaminants found in rainwater.


Dirt, rust, sand and microplastics fall into this category.

Sediment cartridges are the most popular method for removing dirt, rust, sand and microplastics in residential applications. They’re available in a wide range of pore sizes and flow rates and are often installed as a prefilter before RO systems, UV systems and carbon filters to extend their life or enable them to perform effectively.

Bag filters are sometimes recommended for higher flowrate applications, such as for commercial building water supplies. The initial setup cost is typically higher than a cartridge filter, but the replacement filters are cheaper when comparing cartridge filters with the same flow rate.

Backwash filters are commonly used in applications with high sediment levels. They’re designed with a backwash mechanism for cleaning the filtration screen when it becomes clogged with sediment. The cleaning mechanism can be activated manually or automatically depending on the model. The filtration screens come as a standard 100 microns and are often used as a prefilter to extend the life of finer downstream filters.


Water softeners remove or reduce the amount of dissolved minerals, such as calcium and magnesium, in hard water. This makes the water "softer" and less likely to leave mineral deposits. Soft water also makes soap more effective and easier to rinse off. Water softeners are commonly used in homes and businesses to protect tapware, shower screens, windows, and appliances. From a health perspective, softer water is better for your skin and hair.

Water conditioners modify the structure of dissolved minerals to make them less likely to build up on appliances, shower screens and tapware. The key difference to water softeners is that water conditioners do not remove the minerals. This means that you may still experience slight scale build-up.  If mineral build-up does occur, it’s easier to remove than if a water conditioner wasn’t used, but water conditioners don’t eliminate scale build-up completely.

In general, a combination of filtration methods may be needed to effectively filter out all the contaminants that may be present in your water. Head over to our products page to find a filter system specifically designed for your water type.

What size filter system do I need?

Filter systems are designed in many sizes to suit different water flow rates. For household and industrial use, we recommend choosing a filter system that’s sufficient for your peak water-usage. This will ensure you don’t restrict your water flow or pressure.

A straightforward way to choose the filter system size is to base it on the number of people in the household. Product specs often contain information on the household size the filter system is capable of supplying.

A more accurate way is to total the estimated flowrate of each shower, tap and appliance that would be in use at the same time, and compare this with the stated flow rate capacity of the filter system. Here are the typical flow rates to allow for:

-          Shower:                9LPM

-          Toilet:                  9LPM

-          Washing machine:    15LPM

-          Dishwasher:             11LPM

-          Tap:                     7LPM

A household with 2-3 people typically uses less than 45 litres per minute while a household with 4-6 people typically uses less than 70 litres per minute.

What will installation and maintenance cost?


Many filter systems can be installed yourself with basic DIY skills. Alternatively, you can ask your local plumber for an estimated installation price. We recommend the assistance of a plumber if you are making any modifications to the existing mains water pipework. Some filter systems require power to operate. If you need a new power point installed, factor in the cost of an electrician.

Future Maintenance

Most filtration systems require maintenance to ensure they’re treating your water properly. Filter cartridges typically require replacement every 6-12 months and sometimes sooner depending on your water quality and the amount of water you are filtering. UV disinfection lamps usually last for 12 months and water softeners usually need salt to be replenished multiple times each year. Check in the product specs for the required maintenance frequency and the cost of consumables.

To find out more, visit: What does it cost to install and maintain a home water filter system?

Additional checks:

-          Product & company reviews

-          Product warranties

-          How long the filter company has been in business (ensure  you have access to a reliable supply of spare parts)


Ready to choose your filter system? Explore your options!


Should I filter the water going to my whole house or just my drinking water?

This depends on your requirements and budget. In general, it’s worthwhile filtering drinking water more thoroughly than your whole-house water. It’s relatively cheap to get a high-quality filter if it only needs to purify a small amount of water. If you can afford it, using a combination of both a whole-house filtration system and a dedicated drinking water system with a higher level of filtration works effectively, as the whole-house filtration tends to increase the life of the finer filters downstream. If you only require basic filtration for your drinking water, often a whole house filtration system is sufficient, and conversely the same is true for under-bench drinking water systems.

Can I use a reverse osmosis system to filter all the water going to my house?

Reverse osmosis systems are not recommended for whole-house installation as RO water is not always compatible with plumbing and tapware found throughout your house. This is particularly true for older homes with tapware that contains high-concentration lead-alloys. RO also sends around 80% of the feed water to waste, so for a whole house application, using an RO system could increase your water usage significantly.  Residentially, RO systems are best used for under-bench installations.

How can I remove PFAS from my water?

Contaminants such as PFAS can be costly to remove.  If you’re concerned about PFAS contamination in your area, we recommend firstly taking a water sample to a local water testing laboratory. The lab can test your water and provide you a definite answer on whether you have PFAS in your water supply. Reverse osmosis is the most effective method of removing PFAS from drinking water. Due to the serious health risks of drinking PFAS polluted water, we recommend conducting frequent water tests of the purified water to ensure the filtration system is providing adequate protection. If there is PFAS contamination in your area, it may also help to speak with your local council to find out if they have any existing protection measures in place. Detailed studies completed by the government are often shared with the public.

Is it bad to filter the minerals out of my water?

Our view is that filtering 100% of the minerals from water is bad for your health. However, if you’re filtering water that starts off with a high mineral concentration, such as mains water sourced from bores or dams, reducing the amount of minerals to a natural level is completely safe. Rainwater typically has a TDS of 20 mg/L or less. If you filter mains water with a TDS of 400 mg/L with a reverse osmosis system, the pure water will still have a TDS of approximately 16 mg/L, about the same as rainwater. If you feel it’s important to have extra minerals in your water, you may want to consider installing an alkalising filter cartridge in the final stage of your filtration system.

Have more questions?

If you have any questions about which water filter is right for you, or if you're not sure how to install your new water filter, we can help. We’re with you every step of the way so feel free to email, web-chat or call 1800 446 500.