Whangārei Heads Wastewater Scheme

Wastewater systems are designed to take the wastewater that comes from showers, baths, washing machines, toilets and other household or business sources from the property to a wastewater treatment plant, where it is treated before being disposed of.

In Whangārei Heads, wastewater from household connections flows through wastewater pipes and is pumped to the wastewater treatment plant on Kioreora Road via a series of pump stations. 

The pump stations store wastewater for a while and, when they reach a certain level, the pump sends a manageable amount of wastewater to the next pump station along the pipeline. 

This system depends on every pump along the line working properly, and pumping out at the right time to a storage tank that is empty enough to take the new load.

This cycle works well when wastewater is coming into and being pumped out of the system steadily, but not when there are big fluctuations and very large quantities of wastewater mixed with stormwater coming into the tank very suddenly. When that happens, the tank can be overloaded and there can be an overflow. 

We have carried out a pilot study in Parua Bay aimed at determining where stormwater is entering the wastewater system, focusing on the area immediately upstream of the storage tank where the majority of connected Parua Bay properties are located.

The study was completed in May 2025, revealing issues within the public network as well as on some private properties.

Smoke testing showed remedial work was required at various manholes on public and private land, including sealing and repairing lids, particularly those located in low-lying areas that are susceptible to flooding. 

Evidence of H₂S attack was also found, which is where a build-up of hydrogen sulfide causes corrosion of a manhole’s walls, making them vulnerable to stormwater and groundwater leaking into them.

Remediation of these issues, which involves sealing all damaged manholes, and using CCTV to check and then repair the pipes feeding into them, is being carried out by our stormwater and wastewater maintenance contractor. 

We also engaged with the owners of properties within the pilot study area through surveys and site visits, to explore whether stormwater could be entering gully traps from downpipes, which ultimately feed into the wastewater network.

While most gully traps on private property are in good condition, there are some that are damaged, incorrectly sealed or set too low, making them susceptible to stormwater inflow. 

Others are located in areas that are prone to flooding and could be overtopped in rainfall events, and some properties also have stormwater being directed into gully traps via downpipes. 

We are following up with these property owners to ensure the issues are corrected.  

Find out more about smoke testing:

Smoke testing in our wastewater network 

The Parua Bay system is connected to and therefore impacted by what happens further up the catchment. 

Our monitoring has indicated that stormwater is entering the system from the Taurikura Bay and McGregors Bay catchments, which is why we will be extending the pilot study to this area next. 

Identifying and remediating inflow issues (and infiltration) within this catchment will enable us to further protect the wastewater system in Whangārei Heads from stormwater and resulting overflows. 

This work will follow the same model as the pilot study in Parua Bay, beginning with a questionnaire for residents. 

The questionnaire seeks to understand any ponding or flooding related issues that tend to occur during rain events on or around private properties. It will help to highlight any wastewater and stormwater drainage issues, as well as possible fixes. 

The questionnaire will be followed by property inspections, as well as smoke testing of the public system to pinpoint where stormwater may be entering the system through manholes and pipes. 

The volumes flowing into the wastewater system are being monitored 24/7 via flow meters located at several pump stations in the area and level sensors at the Parua Bay pump station storage tank. 

While investigations continue, we are emptying out the storage tank(s) by sucker truck from time to time to ensure levels don’t get too high and lead to an overflow. To help reduce the odour, we have modified the storage tank lids so they don’t need to be fully opened.  

There have been no spills recorded at the sewer pump station on Ritchie Road since 1 January 2025 (which was the result of a failed alarm), and no overflows at the Parua Bay sewer pump station since July 2024. 

Throughout our investigations to date, we have been providing regular updates to community groups via email and meetings, and keeping the broader community updated via a public drop-in session and local newsletters. 

We are also keeping information on our website updated as things progress. Those interested can subscribe to this webpage and be notified when it is updated. Do this by clicking ‘Subscribe to this page’ at the bottom of this page.  

In addition to investigating and remediating stormwater inflow issues in the short term, which will help free up capacity in the system, we are looking at more medium- to long-term options to improve the system and increase capacity. 

Our wastewater team is currently carrying out an ‘optimisation study’ to understand how we can speed up wastewater flows from Whangārei Heads into town and assist with capacity. 

Options currently being looked at include modifications to existing pump stations, introducing new pump stations, and replacing pipelines in strategic areas so that wastewater is able to flow more easily. 

We expect to make optimisations of this nature in the short to medium term (one to five years). 

We are also in the very early stages of assessing the feasibility of a new treatment plant in the Whangārei Heads area, which would service the wastewater network from Parua Bay to Urquarts Bay. 

This is not included in Council’s current Long Term Plan (to 2035), but will be important to ensure the system can manage projected growth in Whangārei Heads in the future.