St Marys Bay separation project

A water quality improvement programme to reduce overflows and clean up local waterways.
Start–finish: 2020-2024
Location: St Marys Bay
Status: Planning and consents
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Why is the project needed?

We’re separating the old, combined stormwater and wastewater pipes in St Marys Bay. This includes separating the public network and also private property drainage. The work will significantly reduce overflows into St Marys Bay and the Waitemata Harbour.
Refer to the map below which shows the general catchment area for St Marys Bay.

St marys bay separation project catchment map

What's involved?

To separate the current combined pipes, we need to build a whole new network, effectively making two pipelines, one for wastewater and one for stormwater. At the same time, we will also undertake separation of combined private property drainage pipelines and connect these into the corresponding public pipes. The project is jointly funded by Watercare and by Auckland Council's water quality targeted rate. The separation of private drainage is also funded as part of the project at no cost to property owners.
The scale and extent of both public and private property drainage means there will be a lot of construction work required across the St Marys Bay area. We will need patience and support from the community as we embark on this huge task. Read more about what to expect during construction of the new public network or find out more about what to expect for private property separation. 

What's happening now?

We have begun the process to apply for the necessary consents starting with the Eastern parts of the catchment. While much of the work will be done in the road as it is designated for this purpose. Some of the public network will also require resource consents for environmental effects such as vibration, ground settlement and works near trees that require careful management and monitoring.
We are continuing to work our way through the area undertaking investigations of the current network and have now completed a preliminary design for the public network. Read more about the factors that go into the design of our new public network.
Our contractors are still working from property to property undertaking further investigations of private property drainage. There are approximately 455 properties that may require private drainage separation so don’t be concerned if we have not made it to your property yet, we are still working our way through investigating each property’s unique drainage and talking to owners about our findings. Our engineers will then design and present to the owners the most practicable option to create a separate network for each property.  

We will continue to work with affected residents directly as we work through planning toward construction and update you as the project progresses. We are aiming to start construction later in the year or early next, once planning is complete.

Timing of the works

St Marys Bay timeline of the works

If you would like to understand the different stages and what’s involved in more detail, please refer to sections outlining each stage of the process below:

Background information

Find information about the current network, history of the network and why the project is needed.


In order to design the new network, our contractors will be undertaking investigations of the public and private drainage in the area.

Designing the new infrastructure

Design elements of the new public network and private drainage.

Property owners information hub

If you require separation work on your property, information about the process can be found here.

Consent applications

Find information on what consents will be required and related documents.

Undertaking construction

Find out what you can expect from construction works in the area.

Any questions?

Frequently Asked Questions
If you have any questions or would like to sign up to receive updates and our newsletters, please email: [email protected]

Further information

Preliminary design new public networks

Project newsletters

June 2020 newsletter
April 2021 newsletter

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