At least 60 Olympic swimming pools worth of wastewater and sewage has been leaching into Auckland's Hobson Bay every year since 2017.
Auckland's Hobson Bay beach. Photo: 123RF
Locals who fear their health is at peril are frustrated it might take more than a decade to fix.
Remuera resident Elise Townsend, who takes her dog walking in Shore Road Reserve, said it was common to encounter foul smells, spilled paint and nasties in the stream, which wends its way down into Hobson Bay.
A few years ago her husband would go kayaking in the bay and even catch fish - now her family is giving all the local waterways a wide berth, even keeping the dog on the leash.
"In the stream the top of the water is completely covered by what looks like soap bubbles so it's still very apparent even just to the naked eye that there are things going into our waterways that shouldn't be," she said.
That's despite 18 months of work from the council to patch up pipes, after a group of Remuera residents sounded the alarm when they saw raw sewage in their local streams last April.
At the time water samples showed five streams had high E coli levels, including peaks of up to 1.1 million units of E coli per 110 ml, 2000 times over the limit to be a health risk for swimmers.
Auckland Council said there were two separate types of contamination. One was from wastewater pipes with limited capacity that automatically overflowed into local waterways in wet weather.
In dry weather, it said, broken pipes and connections from ageing infrastructure could also cause spontaneous spills of sewage.
Auckland Council Safeswim programme manager Nick Vigar said the council had been undertaking repair work to get the dry weather issues fixed.
He hoped within "six months to a year," all the streams would meet public health guidelines.
"To be frank those dry weather issues should not be happening, so that's what we're currently doing in Hobson Bay and have been doing for the last 18 months. We've made pretty good inroads on this. We still have extremes that are exceeding guidelines - but just barely and certainly not by hundreds of times," he said.
However, Remuera resident Margot Nicholson said the council had not started work on the wet weather problems which were responsible for the bulk of the contamination - some 150,000 cubic metres of wastewater that spills into Hobson Bay each year.
That is the equivalent of 60 Olympic swimming pools a year, or 5000 busloads, almost half of which comes from Newmarket Stream.
Nicholson's environmental community group Hapua Thrive has been pressuring the council to do more.
She said the wet weather overflow could not be left unchecked.
"Everyone accepts that they don't want poo in the water and accepts that the problems are complex. But we know the facts now. We have a real problem with the ongoing maintenance and inspection of our existing system as well as making it workable for the growth that we have - and the expectation that sewerage does not get flushed out to sea. We're really unhappy that flushing is seen as a way of dispersing sewerage. it's not treating sewerage and it's not okay.
"That's everything that goes down the sink. That's all your poos that go down the toilet. That's hundreds of different types of viruses including Covid, bacteria and parasites. It's a really significant public health issue," she said.
However, the council warned there was no quick fix for the wet weather issues.
Watercare head of external and strategic relations Brent Evans said fixing the issues involved big investment in upgrading the pipes.
The council has put aside $441 million for asset upgrades as part of a 10-year-work programme, and planning is underway for several major projects.
Evans said a lot of the work was dependent on the $1.2 billion Central Interceptor being constructed. It is currently due for completion in 2026.
"That will create some capacity to allow us to do other works and and those include upgrades to the Newmarket Gully, which is a big one... but it will take time," Evans said.
"In terms of time frames: we're probably talking later this decade in terms of some of the big investment and the network upgrades for Newmarket Gully and and then those upgrades will go right through into the into the 2030s as well."
Vigar said the work programme also had to fit around the council's provision of funding.
"Council doesn't have a lot of money budgeted until halfway through this current long term plan."
Those time frames did not sit well with Townsend.
"I would hate to see the no-swim signs, keep out of the water signs, in our community for ten years. If they think that's what it will take to fix the problems then I think that's completely unacceptable," she said.
Vigar said the council would keep working at Hobson Bay until there was no traces of human waste.
In the meantime, the bay has been added to the Safeswim website to provide people with up to date information about the public health risk.
Evans said there was "real work going on to try and resolve some of those those challenges".
"It is frustrating for for some in the community, but I think what's happened in the case of Hobson Bay is that the community and their elected representatives and others have come together with Watercare in with Healthy Waters to really shine a spotlight on the issue."