Water quality

The quality of our drinking water is regularly monitored and analysed against the values in the Australian Drinking Water Guidelines. This allows us to monitor the physical, chemical and microbiological properties of our drinking water. Our water consistently meets these guidelines and is safe to drink.

Water treatment across the Clarence Valley 

Water from the Nymboida River or Shannon Creek Dam is treated at the Rushforth Rd water treatment plant located just outside of South Grafton. The treatment process involves prechlorination, pH correction, UV treatment, chlorination disinfection and fluoridation. The water is then distributed throughout the Clarence Valley using a network of pipework and reservoirs.

Water for the lower river areas (such as Maclean, Yamba, Iluka, Brooms Head etc.) is piped to a 21ML reservoir at Maclean. Due to the long distance the water travels, the chlorine residual is very low by the time it reaches this reservoir.  For this reason the water is re-chlorinated at the 21ML reservoir to ensure a lasting residual, which protects the water from any sources of recontamination in the distribution system. The water is then distributed throughout the Clarence Valley using a network of pipework and reservoirs.

Minnie Water and Wooli water is sourced from the pristine lakes of Lake Minnie Water and Lake Hiawatha. The water from both sources is pH adjusted and chlorinated prior to being stored in reservoirs and distributed to the villages.

Monitoring water quality 

We take more than 20 drinking water samples each week, which are analysed independently at a NSW Health laboratory against the values in the Australian Drinking Water Guidelines. Our water consistently meets these guidelines and is safe to drink. 

If ever the water does not comply with the health limits set in the Australian Drinking Water Guidelines and is unsafe for drinking, we will inform the community as soon as possible.

Monthly Water Quality Results(PDF, 133KB)

Why is my water discoloured? 

Our drinking water is unfiltered, so may appear discoloured at times. The cause may be related to sediments in the pipes, or the colour of the sourced raw water. 

Dirty water: Dirty water is caused by sediments in pipes. When there is a sudden increase in the rate of water flow through pipes or a change in direction, it is possible to stir up sediments that have settled in the pipes over a period of time. These sediments are then suspended in the water, resulting in a discoloured appearance. Although unsightly, the suspended particles that cause discoloured water are harmless to health. The sediment can contain very fine iron and manganese particles. If you experience dirty water, we advise you to try running the water for a few minutes to check if it will come clean. If you've already done this and the water is still dirty, call us on 02 6643 0200.

Discoloured water: According to the Australian Drinking Water Guidelines, colour is an aesthetic rather than a health issue and "due mainly to the presence of dissolved organic matter". As our water supply is not filtered there is little we can do to alter the colour of the water, but we do monitor water colour at the source and make sure we extract from the best available raw water source. Flushing water mains does not address the colour issue.



Chlorine is used to disinfect the source water. To ensure the water remains safe to drink as it travels throughout the water distribution system, it is mandatory for the water to have a residual of chlorine. Chlorine will dissipate over time, if you keep an open jug in your fridge or on your benchtop, any chlorine taste or odour will dissipate over time.



Rust stains

In some older houses, galvanised pipework can become corroded causing the water to appear rusty when the tap is first turned on, especially after times of no use, like after holidays or even overnight. Regular flushing of the internal pipework can help but eventually the corroded pipework will need to be replaced.


Staining on plumbing fixtures

Samples for chemical analysis are undertaken on a monthly basis and analysed by the NSW Health laboratory in Sydney to determine compliance with the Australian Drinking Water Guidelines. Copper is tested in each monthly sample to ensure levels are within the guideline limits, however, copper pipe corrosion can still occur within internal household plumbing. Corrosion of copper pipes can cause low levels of copper to leach into plumbing fixtures, sinks, baths etc. which can result in green/blue stains on white surfaces, especially in bathrooms that aren't used regularly. Regular flushing of your internal lines (for at least 30 seconds) and ensuring leaking tap washers are replaced should reduce the staining problem. 


Remember: It’s important to thoroughly flush your internal lines upon return from a long absence, to ensure stagnant water which may have a high copper content is removed and not consumed. Use a tap at the back of the house, furthest from your water meter, to draw water through your internal pipework.

Soft water

Prior to treatment, our raw water supply is classified as very soft water. Very soft water is extremely corrosive over time to household pipes and fittings, resulting in costly repairs of internal pipes and fittings. To combat the water softness, lime is added to the water prior to disinfection, changing the pH of the water to ensure that household pipes and fittings are not eaten by the soft water.  

The lime can be deposited in hot water systems and kettles, and can often be seen as a brown discolouration in kettles.  An easy way to remove lime deposits from your kettle is by boiling equal parts vinegar and water in the kettle and allowing the solution to sit for at least half an hour. 

Check your hot water system owner’s manual for advice regarding descaling.