St Marys Bay Water Quality

Used year round for learn to sail, kayaking, paddling, dragon boat racing, water safety training and events, St Marys Bay is the public focal point of Westhaven Marina. It is also used by around 1,500 walkers, runners and cyclists each weekday - more on weekends, and it is a focus of attention in both Panuku Development Auckland's Waterfront Plan, and the Westhaven Plan.  

The Resource Application for the St Marys Bay - Masefield Beach Water Quality Improvmenet Project is now closed for submissions. Please click here to view the application. 


The Project 

In 2015, in response to visible signs of pollution and odours, Panuku Development Auckland, along with other Auckland Council teams, began to monitor water quality in the bay and found that it suffered from increased concentrations of bacteria, and heavy metal contamination. 

In 2016 a working group was established enabling Auckland Council’s Healthy Waters team, and the CCOs Watercare, Panuku Development Auckland and Auckland Transport, to bring about improvements in water quality more quickly.

Causes of pollution

Following a period of investigation and water testing, the primary cause of water quality issues in St Marys Bay was identified as the combined stormwater and wastewater network used by properties in the adjacent suburb. This type of network dates back to the early twentieth century, and carries both wastewater and stormwater in the same pipes and it regularly overflows and releases stormwater and sewage into the bay. 

Other contributors are likely to be: 

  • Vessels discharging waste illegally: While Westhaven Marina is a no discharge zone and this is actively enforced, it’s possible that boats do from time to time discharge untreated sewage into the marina even though sewage removal facilities are available.
  • Antifouling paint: More environmentally friendly antifoul products and alternatives to antifoul are being developed and coming onto the market, and improved facilities for applying and removing antifoul are also available. 
  • Stormwater run off from roads and other surfaces contains heavy metals, sediment and solids, and the marina’s carparks are now fitted with a number of devices to clean and filter this water.
  • The large bird population living within Westhaven that may slightly elevate bacterial levels, as will dogs using St Marys Bay Beach, and even polluted water entering the marina from other locations in the harbour.   


Health & Safety

If you are using St Marys Bay for watersports, please check the SwimSafe website through summer, and be cautious about coming into contact with water for 48 hours after heavy rain.  


Short, medium and long term solutions 

While planned solutions are on the long term horizon, the project team are seeking to bring forwards improved water quality outcomes for St Marys Bay. 

Solutions that were immediately implemented included:

  • the introduction of SafeSwim monitoring in the bay to better inform users of the bay about water quality 
  • the installation of 100 TetraTraps in the adjacent residential area 
  • installation of and an automatic sensor to enable operations staff to quickly resolve any dry weather overflows from the network 
  • Panuku Development Auckland as managers of Westhaven Marina took a hard line on any boats found to have illegally discharged sewage into the bay, along with a range of ongoing environmental initiatives

the st marys bay - masefield beach water quality improvement project

Auckland Council proposes to undertake a major infrastructure project to reconfigure the existing combined sewer and stormwater network at St Marys Bay and Masefield Beach. This project is designed to integrate with long term network improvement plans being developed by Healthy Waters and Watercare which will further reduce combined sewer overflows and improve water quality.  


Updates AND DOCUMEnts  

The project team has undertaken to keep all stakeholders regularly updated on this project and we will post updates here as they become available:  

Letter and frequently asked questions (July 2018)

Timeline: your network now and in the future (July 2018)

Project description (July 2018)

Resident Newsletter (re Public Notice) May 2018

Resource Consent Application (notified) 

Project overview - an easy to understand summary of need, project design and outcomes - March 2018

Recreational Uses of St Marys Bay and Masefield Beach - November 2017

PowerPoint presentation - prepared for St Marys Bay Residents Association 8 November meeting 

October 2017 - Update re St Marys Bay - Masefield Beach Water Quality Improvement Project (6mb) - includes invitation to public meetings and details of ground investigations 

October 2017 - Detail of concept alignment (engineer's map) 

July 2017 - St Marys Bay - Masefield Beach Project overview document (6mb)

July 2017 - Frequently Asked Questions resulting from information sessions 

June 2017 - Information session handout with project details and diagrams

May 2017 Introduction to key infrastructure project and notice of meetings

April 2017 Notification of ground investigations - also click here to view map

March 2017 Update to residents of St Marys Bay 

January 2017 Update to residents of St Marys Bay  

To receive our email updates on the St Marys Bay - Masefield Beach Water Quality Improvement Project, please email