What is happening?

Seqwater is enhancing water treatment processes at its Mount Crosby and North Pine water treatment plants.  

The enhanced treatment processes will deliver benefits to the Ipswich, Brisbane, Logan and Moreton Bay regions. Enhanced treatment will help stabilise water quality, including in summer when it needs to be more closely managed.  

The initiative is being undertaken in partnership between Urban Utilities, Unitywater, Logan Water and Seqwater. This initiative is due to be completed in the second half of 2025. It will make sure water continues to be delivered within Australian Drinking Water Guidelines. 

A key result will be strengthening the water quality by slightly increasing the pH level from about 7.8 to about 8.4 at the Mount Crosby and North Pine water treatment plants.  

Seqwater and Logan Water will continue to test water in the water supply network to make sure it meets strict water quality guidelines. 

Most customers are unlikely to notice a change in their drinking water. 

Customers who treat their water or have specific water requirements may need to make adjustments to allow for the change in pH.

What is pH in the water?

pH is a natural part of water and measures how acidic or alkaline a substance is on a scale from 0 to 14. A pH of less than 7 is acidic, 7 is neutral and greater than 7 is alkaline. 

Our everyday drinks vary greatly in pH – soft drinks are about pH2.5, orange juice pH3.8 and milk pH6.7.  

Australian tap water varies in pH between about 6 and 10.8, as does bottled water.  

The Australian Drinking Water Guidelines’ recommended range for pH in the water supply is 6.5 to 8.5. This range is recommended to minimise corrosion in water networks and is not a health-based guideline.  

Why is the change needed?

While well-established water quality management processes are in place, the enhancements will help maintain water quality into the future by further stabilising water disinfection.

How is the water quality enhanced?

Increasing the pH level from about 7.8 to about 8.4 will further boost the effectiveness of disinfectants added to the water supply year-round. 

To increase the pH level of the water, a carefully measured amount of a chemical compound called Sodium Hydroxide is added during the treatment process at the Mount Crosby and North Pine water treatment plants. This compound is commonly used in everyday items like medicines, soaps, and detergents. This adjustment is in accordance with the Australian Drinking Water Guidelines, ensuring the water remains safe for consumption while enhancing its overall quality. 

Seqwater regularly makes minor adjustments to the drinking water supply to enhance its quality in line with the Australian Drinking Water Guidelines. This is because water is a natural product and its chemistry is determined by factors such as the climate, rainfall, vegetation, land use, geology and water flow in our water supply catchments.

Why does water quality need to be more closely managed in Summer?

In warmer temperatures, disinfectants decay more quickly and are more difficult to maintain for longer periods. The increased pH will further boost the effectiveness of these disinfectants year-round.

How does increasing pH boost the effectiveness of disinfectants?   

To make water safe to drink, multiple treatment processes are carried out at Seqwater’s water treatment plants.  

Chlorine is then added in a process called disinfection. Adjustments are made at the water treatment plant to regulate the pH level of the water. 

Before the water is released into the SEQ Water Grid, chloramine is added to maintain disinfection as it travels through the water network to homes and businesses. This process is known as secondary disinfection.  

A higher pH will help maintain the concentration of chloramine in the water for longer to protect the water as it travels through the network. 

Will this affect my drinking water? 

Water will continue to be delivered within Australian Drinking Water Guidelines and customers in the supply areas are unlikely to notice a change in their drinking water.  

Some customers who already treat their water or have specific water chemistry requirements may need to make minor adjustments to allow for the change in pH.

Who is managing the change?

South East Queensland’s bulk water supplier, Seqwater, is leading this initiative. It is being undertaken in partnership with Urban Utilities, Unitywater and Logan Water.  

Business customers

What do I do if I think this affects my business?  

Your water will continue to be delivered within Australian Drinking Water Guidelines and customers are unlikely to notice a change in their drinking water.  

Some customers who already treat their water or have specific water chemistry requirements may need to make minor adjustments to allow for the change in pH.  

If you are uncertain about your water chemistry requirements, you may wish to seek advice from a water quality specialist.  

Will I be compensated for making changes at my business for a higher water pH?  

As the pH change remains within the Australian Drinking Guidelines, compensation is not available. While we empathise with your circumstances, we need to consider any expenditure, including the cost of compensation, in the context of being fair to all our customers.  

If you have concerns that the increased pH will cause substantial financial hardship, please contact us to discuss your situation.  

We need to make changes in our business to adjust to a higher water pH. Can we have more time to do this?

It is important that Seqwater, Urban Utilities, Logan Water and Unitywater continue to implement the water quality enhancements in the second half of 2025 to further stabilise water quality for the benefit of all customers. We have been endeavouring to contact as many potentially impacted customers and businesses as possible since early 2024. However, unfortunately we don’t have detailed information about all the businesses in our service area, as many are not our direct customers.    

Changes needed to adjust to a higher water pH are expected to be relatively minor for most businesses. These include changes to chemical dosing or ongoing maintenance activities.   

However, if you are concerned changes for your business may take longer to implement, we would be happy to discuss your individual requirements further. I can arrange for someone to get in touch with you.  

Why haven’t you contacted me sooner to give me time to prepare for the change?

We have been trying to contact as many potentially impacted customers and businesses as possible since early 2024. We don’t have detailed information about all the businesses in our service area, as many are not our direct customers.    

Changes needed to adjust to a higher water pH are expected to be relatively minor for most businesses. These include changes to chemical dosing or ongoing maintenance activities.   

It is important that Seqwater, Urban Utilities, Logan Water and Unitywater continue to implement the water quality enhancements in the second half of 2025 to further stabilise water quality for the benefit of all customers. If you are concerned changes for your business may take longer to implement, we would be happy to discuss your individual requirements further. I can arrange for someone to get in touch with you.  

Will the increase in pH from about 7.8 to 8.4 affect other aspects of water composition such as hardness and alkalinity? 

The slight increase in pH will not affect water hardness but is likely to have minor impacts on alkalinity, conductivity and scaling potential. The table below outlines some indicative changes to the chemical composition of drinking water following the pH increase. Water will continue to be delivered within the Australian Drinking Water Guidelines.  

Residential customers 

I am a resident. What do I need to do?  

Most customers won’t notice a change in the appearance or taste of their drinking water. We recommend you continue your regular water-using appliance maintenance and cleaning to prevent scale build-up.  

I am a home dialysis patient - what adjustments may be needed? 

Dialysis patients should continue routinely testing their source water and making adjustments as needed to achieve the required water chemistry. This may include changing water treatment regimes to remove chloramines. 

I have very sensitive skin – will the increased pH affect me?  

People with significant wounds or sensitivities to water pH levels should take appropriate care when dressing wounds and bathing. Please check with your healthcare provider if you have any questions. 

I have pet fish / a pond / an aquarium - what adjustments may be needed? 

Tap water needs to be treated to maintain healthy fish, turtles, frogs, axolotls or other creatures in ponds and aquariums. This includes removing chlorine and chloramine and adjusting the levels of pH and minerals to suit the specific needs of your pets. Your local pet store can provide advice including how to choose suitable filters or chemicals, such as an aquarium water conditioner, as needed. 

How do we find out more?  

You can find out more about these changes by visiting SEQwater Water treatment or by contacting Logan Water on 3412 3412 or email watercomms@logan.qld.gov.au.