High St South water main upgrade

Overview

As part of our water renewals programme, we’re replacing the aging asbestos cement (AC) water main along High Street South with modern, durable pipelines. This work will strengthen Carterton’s water network, ensuring consistent supply and dependable performance for years to come.

By upgrading now, we’re reducing the risk of unexpected disruptions and making future maintenance simpler and less intrusive. It’s a practical step toward a resilient system our community can rely on well into the future.

What's happening?
We’re renewing the High Street South water main between Moreton Road and Victoria Street.
This involves the replacement of the 250mm AC water main installed in 1963 with two new pipelines:

    • A 300mm PVC pipeline in the western shoulder of the highway.
    • A 63mm PE rider main in the eastern shoulder.
Why is this important?
The current AC pipes are aging and in poor condition, posing risks to our water supply. These new pipelines will improve water pressure, flow, and reliability.
In addition, this project will make future maintenance easier and reduce traffic disruptions when maintenance work is required.
Who is managing the project?
This work is being carried out by local business, G&C Diggers, with oversight from our Carterton District Council projects team.
Key milestones
Pre-construction activities: November–December 2025.

Pipeline installation: January–November 2026.

Pressure and chlorine testing on new pipes: After each stage has been constructed.

Pipeline livening and cut-overs: Coordinated with planned water network shutdowns.

Final reinstatement: Completed after each stage.

How will the work be done?
Open trench method: This approach involves digging a trench along the planned pipeline route, placing the pipe inside the trench, and then backfilling and compacting the trench once the installation is complete. This approach is often chosen for projects where:

    • The pipeline is relatively deep or large in diameter.
    • Ground conditions allow for safe excavation.
    • There’s enough space to manage temporary traffic and safety measures.

Pipeline installation: We’ll install the 300mm PVC pipeline at a depth of 1.5m, and the 63mm PE pipeline at 1m depth.

Reinstatement: Asphalt hotmix will be applied weekly to ensure smooth road surfaces.

Daily hours of work
Our teams will be on site from 7:00 AM to 5:00 PM, Monday to Friday.
At some points, this project will involve overnight works to minimise disruption to traffic. More information will be provided closer to the time.
What about traffic and pedestrians?
Temporary traffic management (TTM) will be in place to minimise disruption.
Pedestrian crossings and bus stops will be temporarily relocated during construction. These will be well signposted.

Contact us

Phone: 06 379 4030
Email: info@cdc.govt.nz

Thank you for your understanding and cooperation.

Timeline

Stage 1
L
Stage 1

Moreton Road to Costley Street

430m in length, works expected to last from 6 January through to April 2026.
Stage 2
L
Stage 2

Costley Street to Rexwood Street

393m in length, works expected April to July 2026
Stage 3
L
Stage 3

Rexwood Street to Victoria Street*

Should budgets allow, the project will extend to include Rexwood Street to Victoria Street – a length on 282m, August through November 2026.

FAQs

Why is this project necessary?
The current water mains are made of asbestos cement and are over 60 years old. Replacing them ensures a safe and reliable water supply for Carterton residents.
How will this project affect traffic?
To minimise disruption, the worksite will be limited to 50m sections at a time. Both lanes (northbound and southbound) will remain open for the majority of the construction period. Temporary traffic management measures will be in place.
Will my water supply be affected?
There will be planned water network shutdowns during the change-over process from the old main to the new. Affected residents will be notified in advance.
What measures are in place for safety?
We’ll ensure thorough Health and Safety and daily risk control measures are implemented. Traffic management and pedestrian safety measures will be in place throughout the project.
How will the project impact local businesses and schools?
Sensitive and vulnerable stakeholders, including schools, businesses, and healthcare facilities, will receive specific notifications about the construction schedule. Anyone with concerns is welcome to get in touch with our project team should they need to discuss their situation.
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