Stanway-Halcombe Rural Water Scheme Achieves Compliance and Boil Water Notice is Lifted
Manawatū District Council have reached a significant milestone in providing safe and compliant drinking water for users of the Stanway-Halcombe Rural Water Scheme.
Council is now confident that the Stanway-Halcombe Rural Water Scheme meets NZ drinking water standards. As a result, the Boil Water Notice was officially lifted on 24 March 2025, and residents can now enjoy safe drinking water.
The Stanway–Halcombe Rural Water Scheme is a water reticulation scheme operated by Manawatū District Council and supported by the Stanway-Halcombe Rural Water Scheme Committee. The water source is provided from shallow bores adjacent to the Rangitīkei River. The scheme was originally designed to provide stock watering on a restricted flow basis. However in recent years, there has been a reallocation of a proportion of units to lifestyle properties, as farms have been subdivided.
As part of the New Zealand Drinking Water Standards, all water schemes are required to meet protozoa compliance to protect public health. Protozoa are single-cell organisms that can cause illnesses, and their removal from drinking water is essential to ensure the safety of the water supply. To achieve these standards for the water scheme, Council needed to construct and commission a new water treatment plant. This construction and commissioning is now complete.
The new water treatment plant contains filtration to remove the impurities in the water supply, and both a UV and chlorination system provide the protozoa treatment required. The water treatment plant also contains a range of pumping systems to ensure the water travels from the river intake point to the water treatment plant and then to the scheme’s water storage site.
The project to install the new water treatment plant was made particularly challenging by Cyclone Gabrielle’s impact in February 2023. Heavy rain in the upper catchment of the Rangitīkei River led to 100m of river bank washing away beside the scheme’s river water intake point. The loss of bank area means the filtration previously provided by the fine gravels has been reduced and has resulted in occasional turbidity (cloudiness) in the water supply.
As a consequence of turbidity levels, Council issued a Boil Water Notice for Stanway-Halcombe Rural Water Scheme users. This was a precautionary measure, as the water quality was temporarily compromised due to turbidity, and Council were not confident it met the required bacteria standards for safe consumption pending completion of the new water treatment plant project.
In addition to constructing the water treatment plant to address the ongoing risk of increased water turbidity levels, Manawatū District Council partnered with Horizons Regional Council in late 2023 to install a rock wall along the riverbank. This project is now complete, and reduces the risk of further erosion to the water intake point.
In addition to the rock wall, the construction of a 4,000m³ storage reservoir is also underway, which will serve as an additional buffer to maintain water supply to customers during any periods of high turbidity in the water supply that exceed the treatment capability of the new water treatment plant. This project is expected to be completed by May 2025.
Council would like to thank the customers of the water scheme for their patience while the Boil Water Notice was in place. Council would also like to take the opportunity to acknowledge the Karatea whānau for their contribution of family whenua to the water treatment plant upgrade.
Caption: Completed Water Treatment Plant (top left and right). Construction of the rock wall alongside water river intake point (bottom left), Construction of additional storage for 4,000m³ of water (bottom right).