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Changes to Westport and Carters Beach water pressure starting next week

23 Feb 2024

A pressure reduction valve (PRV) that was installed as part of the upgrades to the Westport water supply trunk main will be brought on-line next week. 

Buller District Council’s Manager Infrastructure Delivery Eric de Boer says: “Pressure reduction will begin on Thursday 29 February. We will slowly decrease the water pressure by 50 kPa every two weeks until we reach the optimal pressure of around 600 kPa.”

The new PRV has been installed at the base of the terrace that the water reservoir is situated on, with the pressure reduction affecting the entire townships of Westport and Carters Beach.  

Pressure reduction is the most effective method of controlling water loss through reducing strain on the water infrastructure.

Mr de Boer says: “Currently, Westport’s water supply (measured at Derby Street) operates at a maximum pressure of 1,150 kPa (167 psi), with fluctuations during the day depending on demand. The target for Westport would be about half the existing kPa, which we will look to achieve with the new PRV.”

A kilopascal or kPa is a unit of water pressure measurement. Westport experiences high water pressure due to the location of its water reservoirs, which are elevated on terraces above the township.

The water flows through a steeply declining pipe from the treatment plant to the trunk main. This steep fall builds up significant water pressure.

Because of this, Westport’s pressure is significantly higher than what would be expected from a water supply of its size.

Mr de Boer says: “The high pressure has put a lot of strain on the system. We aim to reduce the pressure to 600 kPa while simultaneously monitoring the network pressure through pressure loggers and addressing service requests.” 

Once the PRV is in place, it will reduce the burst frequency of both public and private pipes, lower water consumption, and reduce damage to private fittings such as hot water cylinders and valves.

Mr de Boer says: “With the combination of pressure reduction and replacement of the trunk main, we expect to see water savings exceeding 1000 m3 per day. Replacement of the trunk main has already achieved an average water loss reduction of 815 m3 per day. This is particularly important, considering the issues we face with the water intake.”

Council will have a series of pressure readers throughout the township which will be actively monitored.

Mr de Boer says: “We aim to have the process completed around mid-May 2024. This will require five iterations of an average reduction of 50kPa every two weeks. We will keep the community informed about the progress during this time.”  

Key things for residents to know

Residents might notice a reduction in water pressure once the new pressure reduction valve is in place. This is normal and an indication that the water is running through the network at a more sustainable pressure.

If residents are concerned that their water pressure or flow rate is less than what is expected and they assume it is due to the water pressure reduction, ask your neighbour if they are experiencing similar issues. If they are, it indicates that the less-than-ideal water pressure could be due to the water supply pressure reduction. In this case, please get in touch with council on 0800 807 239 or via and staff will raise a service request to investigate the issue.

If only your property has less-then-ideal water pressure it indicates that your property’s pressure reduction device may require an adjustment. You might need to contact a plumber to help adjust your pressure reduction valve.

Private pressure reduction devices include pressure reduction valves, pressure regulators or pressure restriction valves, which reduce the pressure within private property boundaries. Since the water pressure for Westport and Carters Beach will be reduced gradually, residents might have to adjust their pressure reduction devices several times, or they may actually become redundant as a result of the process.   


For further information please contact:
Manager Infrastructure Delivery
Eric de Boer