Masterton takes its drinking water from the Waingawa River under a resource consent from Greater Wellington District Council. Before reaching your tap, it is treated at the Kaituna Water Treatment Plant, opened in 1983 about 10km west of Masterton. Daily consumption varies from about 9 million litres per day during winter, to a high of 25 million in summer.
How is my water treated?
Here’s how the treatment process works.
Water is taken from the river by siphon to draw the flow into a concrete main. This travels five kilometers downstream to reach the plant.
Once it reaches the plant, only the amount of water required is stored in three holding ponds until it's needed. Unused water returns to the river. When the river is in flood and dirty, the flow is shut off and the plant can run on its stored capacity for 3-4 days.
From the ponds, water is let into a large concrete vessel or clarifier, where the chemical coagulants PAC (poly aluminium chloride) and polyelectrolite are added to form small floc particles, these attract the fine suspended silt and clays present in the water. These drop to the bottom of the clarifier as sludge.
Five sand filters are used to “polish” the water to a high degree of clarity and remove any residual floc particles. The filtered water is then piped to a covered clear water pond.
Chlorine, fluoride & lime
Metered dosing is carried out at the clear water pond, using chlorine (disinfectant to give protection from micro-organisms that may enter the distribution system), fluoride (for prevention of dental cavities in children), and lime (to raise the pH of the water making corrosion of pipes less likely).
The last storage point before water enters the town water mains is the Upper Plain Reservoir, supplemented by smaller reservoirs on Lansdowne hill. The supply is almost all gravity fed from our reservoirs, with only a limited amount needing to be pumped to the highest point.
Fluoride-free Drinking Water
Council provides fluoride-free water from a dedicated tap installed outside the Manuka Reserve in Manuka Street, Masterton.
Water and our Future
Water main and connection renewals have been programmed over the next ten years at a total cost of $19.9 million. This sum includes the replacement of a trunk main into town that will be staged over the first five years of the plan at a total cost of $7.6 million. Depreciation reserves will only cover some of this work, so some loan funding is also required. Loan servicing and repayment will be funded by urban ratepayers. This work is consistent with our asset management plan and is based on cost-effective management of the asset now and in the future.
Urban Water Consents
Until now, our summer water restrictions have helped us stay within our resource consent limits for taking water from the Waingawa River. We expect that future consents will reduce the amount of water that we can take from the river during times of low flow. With this in mind, we have installed water meters on urban properties and plan to construct larger untreated water storage dams.
Rural Drinking Water Supplies
The Ministry of Health has introduced higher standards for rural drinking water suppliers. We expect this will require improvements to infrastructure and treatment systems, and their ongoing maintenance, so that all rural systems comply with potable (drinking) water standards. A provision of $374,000 has been made to assist rural schemes in meeting these standards. It is expected that these upgrades will be funded by loan and costs spread across the users over the period of the loan.
Details of the MDC and Opaki Water Scheme water supplies are available in the Assessment of Water and Sanitary Services 2018 (PDF, 5.5MB).