Norsewood Water Treatment Plant Upgrade
The Norsewood Water Treatment Plant has recently undergone a significant upgrade to improve water quality and address ongoing concerns about discolouration and sediment in the water supply.
These concerns were raised by the community during engagement meetings, where residents also highlighted longstanding issues with the condition of the water network.
The upgrade ensures the treatment plant meets New Zealand’s Drinking Water Standards and provides safer, clearer water to Norsewood residents.
What has been done?
As part of the upgrade, Council installed new filters with ion exchange media designed specifically to remove the excess iron and manganese found in Norsewood’s bore water. Improvements were also made to the plant’s pre-filtration system (which removes larger particles such as dirt and sediment), chlorine dosing equipment, and new UV disinfection.
An additional 30,000-litre treated water reservoir has also been added to increase capacity and improve the hydraulic efficiency of our storage.
Construction took place throughout 2024 and was completed in August. The plant then entered a commissioning phase, running through to April 2025. This extended period allowed for fine-tuning of the new filters to ensure they consistently remove iron and manganese over time and perform to the highest standard.
During this process, it became clear that issues within the wider Norsewood water network were contributing to water quality concerns. Due to the age and complexity of the network—along with a wide range of pipe sizes—a specialised flushing approach (No-Des – Neutral Output Discharge Elimination System) was required which provided a deeper clean than traditional flushing and does not waste any of the community’s water. Check out the flyer below! The flushing unit will need to return at regular intervals to carry on with further cleaning, this will help ensure that the water quality in the pipes better matches the high standard of water now being produced at the treatment plant.
Early results are promising. Data from the past four months shows the upgraded plant is removing up to 85% of iron and manganese, and water clarity has improved significantly. Turbidity has dropped from 1.05 NTU (measure of turbidity in water) - to between 0.2 and 0.5 NTU.
We now have a better performing treatment plant, cleaner pipes and greater control over the plant for our operators.
Council would like to thank Norsewood residents for their patience while these works were being carried out. Now that the upgrade is complete, and water quality has improved Council would also like to recommend residents to take this opportunity to carry out their annual water tank inspection and clean if required (MoH Guidelines - check out the flyer below). Council will be in touch with the community before the next round of network flushing takes place.
The total combined spend on this project is approximately $500k. This was budgeted for in the 2021-2031 Long Term Plan.
