Auckland sewerage needs urgent upgrade

Auckland’s failing sewerage infrastructure can no longer be ignored. In the older parts of the city, in particular, the wastewater/stormwater pipes, many dating back to the late 1800s, cannot cope with current demands, let alone the pressure from housing intensification. One typical example: Pipes which serviced two properties are now required to handle wastewater from 42 new units on the redeveloped site.

Each year Auckland accommodates an extra 56,000 people – the same size as New Plymouth. Many of these make their homes in the new high rises of the central city where the old sewerage infrastructure is inadequate to service the 40,000 people already living there.

When the sewerage system can no longer cope, often after rain but also in dry weather, “safety valve” overflow outlets discharge directly into the Waitemata Harbour. Forty-one outlets between Pt Chevalier and Kohimarama discharge into some of Auckland’s most popular beaches, where signs now warn against swimming after heavy rainfall.

This is not what Auckland’s “most liveable city” and New Zealand’s “100% pure” image promises, but more importantly, inadequately managed sewage is a threat to public health. E-coli bacterial readings in a local (central isthmus) stream have been recorded at up to 190,000 – the swimmable level is set at 540.

Auckland’s rapid growth has spotlighted housing and transport as two demanding infrastructure issues, but sewerage, long neglected, must be considered as part of this challenging triumvirate. Auckland region is expected to grow from 1.5 million to 2.3 million in the next 25 years. That’s a lot of flushed toilets. We need a long-term solution, and we need to find the funding. Short-term fixes are no longer enough.


• More than 2 million cubic metres of contaminated overflows discharge each year into local waterways and the Waitemata Harbour.

• Currently, these discharges are permitted by resource consents granted by Auckland Council to Watercare Services (a council controlled organisation or CCO) following a non-notified application.

• In the USA, UK and Canada central governments have banned overflows of untreated sewage and introduced regulators to force faster compliance with new water purity standards.

• In March 2017 a coalition of community groups concerned about sewage in stormwater overflows was formed to research the background to this issue and lobby for a more efficient sewerage system. Known as SASOC (Stop Auckland Sewage Overflow Coalition), the group believes that polluted overflows will be largely eliminated if sewage is separated from stormwater – into separated pipes. If this is not totally feasible, then SOSAC seeks removal of a large part of the stormwater from the combined network.

• Combined pipes/separated pipes.
– In older areas combined pipes carry both sewage and stormwater. After rainfall as low as 5mm stormwater can overflow into the wastewater side of the pipe which may then discharge combined sewage and wastewater directly into the harbour.
– Separated pipes are required for all new dwellings and major renovations involving plumbing, but in older areas this separation usually ends at the road frontage, with the separated pipes flowing into an existing combined pipe.

• New builds with separated pipes are also required to install holding tanks, which can retain and then discharge wastewater when the sewerage system is under less pressure.

• The former Auckland City Council adopted a policy of total separation and increased rates to provide for it. However, following the formation of the super city, the funding obtained from the rates increase has been allocated elsewhere.

• In the meantime, the Auckland City Council’s plans for a large collector pipe, known as the Central Interceptor, are going ahead. Running between Western Springs and the Mangere treatment plant, the pipe should increase the capacity of the predominantly combined pipe network in central Auckland. However, overflows cannot be entirely ruled out. SASOC understands that a similar major collector pipe (the Waterfront Interceptor) will be required to relieve overflows in the Western Bays catchment and a Remuera Interceptor may be required for Orakei and Parnell.

• Unless Stormwater is separated from wastewater totally or substantially, the problem will get worse. The recently-established Auckland unitary plan permits increased density in much of the central Auckland isthmus, resulting in increased wastewater. Additionally, in these older suburbs it permits impermeable surfaces to increase from 42% to 62% of the land area, reducing the natural rainfall soakage and increasing the stormwater collection (to illustrate this, the increase potentially creates an extra 2 sq km of impervious surface in two areas with the most alarming overflows, the Meola and Oakley catchments).

• Auckland’s water services are managed by two distinctly separate arms of council, until recently with, apparently, very little, if any, liaison.

¬ Watercare Services Ltd, a council CCO, is responsible for supplying potable water and collecting and treating the city’s wastewater. However, in older areas with combined pipes Watercare is responsible for managing the combined pipes, even though they carry stormwater. Strangely, Watercare is not financially responsible for any stormwater upgrades to that system, only wastewater upgrades.
¬ Healthy Waters, a section of Auckland Council, is responsible for collecting and disposing of stormwater.

• A recently-formed project team, drawn from both Watercare and Healthy Waters, is to report to council on a long-term stormwater/wastewater solution, to be included in council’s 2018 long-term plan. This team is known as CANOPy (Central Auckland Stormwater and Wastewater Network Optimisation Programme). The CANOPy report is due to go to council in August.

• The Stop Auckland Sewage Overflow Coalition has been promised that it will be consulted on this report, before any conclusions are reached as to the optimum solution or the means of achieving it – but not until October 2017. It is unknown whether it will be available for general public consultation.

• SASOC strongly believes that the CANOPy team’s conclusions should:
– be available for early public consultation
– be peer-reviewed by overseas experts.
• SASOC co-convenors, David Abbott and Dirk Hudig, urge voters to discuss this issue with candidates, and ask them the following questions:


1. Will your party support amending the RMA to ensure that wastewater/stormwater overflows cannot continue legally?
2. Will your party support legislation to appoint a regulator to oversee the mitigation/elimination of these overflows (as is the case in Canada, the UK and the USA)?
3. Auckland City is up to its credit rating borrowing limits. Will your party support government financial assistance to alleviate this infrastructure deficit in Auckland?


Co-convenors: David Abbott, chairman, St Mary’s Bay Association and Dirk Hudig, executive member, Herne Bay Residents Association.


Membership is open to all groups who share SASOC’s concerns about the presence of sewage in stormwater overflows in Auckland.
Several groups, representing communities that fringe the inner Waitemata harbour or are located in inland parts of the Auckland isthmus, initially supported the formation of the coalition and were invited to become members after it was established formally. The following have done so to date:
Auckland City Centre Residents’ Group Inc
Freemans Bay Residents Association Inc
Gables Neighbourhood Group
Mission Bay-Kohimaramara Residents Association Inc
Orakei Community Association Inc
The Herne Bay Residents Association Inc
The St Mary’s Bay Association Inc
The Whau River Catchment Trust
Western Bays Community Group Inc

We are still waiting to hear from the following (all of whom were initial supporters):
Eden Park Neighbours Association Inc
Grafton Residents’ Association Inc
Grey Lynn Residents Association Inc
Save Waterview Association Team
Westmere Heritage Protection Association Inc