For more than two years a Bay of Islands property has been flushing faeces into the Waitangi River upstream from the intake for Paihia's town water supply.
The sewage outlet from the home, in the Wātea subdivision at Haruru, is plumbed into a stormwater drain instead of a sewerage pipe.
As a result, raw sewage flows into the river from a stormwater pipe near Spinnaker Pt, upstream from a swimming hole and the water treatment plant that supplies Haruru, Paihia, Waitangi and Ōpua.
The leak is about 300m from the swimming hole and, because the river takes a zig-zag route, 1km from the water intake.
From there the river flows over Haruru Falls, into the Waitangi Estuary behind Te Tii Marae, and into the Bay of Islands.
Wātea resident Simon Harman first noticed a foul smell wafting over his property three to four years ago.
He assumed it was coming from a sewage pump on the neighbouring reserve and thought little of it, until he discovered the odour was in fact coming from a stormwater outlet.
At the pipe exit was a pile of toilet paper and what was unmistakably human excrement.
He thought it was a leak from the sewage pump and notified the Far North District Council.
The staff member he complained to was helpful but, as far as he could tell, nothing happened.
Around that time he was dealing with the loss of his wife so he put it to the back of his mind — until, in early January, he saw a group of children walking up the street after swimming just downstream from the stormwater pipe.
"I thought, I need to make something happen, but how? My mate David was here so I showed him."
David Heller, of Kerikeri, was sceptical about his friend's story at first, then shocked when he saw what was emerging from the pipe.
He lodged a "request for service" (RFS) with the council as soon as staff returned after the Christmas break.
When he received no response he followed up with a second RFS on March 4, then a formal complaint, and a phone call to the mayor's office on April 11.
Heller then received a call from a contractor who told him the leak had been traced to a home where the sewage outlet had been connected to a stormwater drain instead of a wastewater pipe.
When the discharge continued, a frustrated Heller posted some unsavoury photos of the stormwater outlet on social media.
Within 20 minutes he was contacted by a councillor and a council manager, he said.
"Someone in Wātea is knowingly flushing their toilet into Waitangi River. It's just upstream from where people swim and it flows into the Bay of Islands. It's been going on for years. All I want is for poos and wees to stop going into the awa [river]," he said.
Harman couldn't understand why the council didn't demand immediate action.
"They've located the house — why don't they go around with a portaloo and tell the owner to fix it straight away?"
Council infrastructure and asset manager Andy Finch said a member of the public notified staff about a sewage spill in the Haruru area last month.
The council's Three Waters alliance partner, Far North Waters, investigated and located the source.
"This was not an easy task and eventually required a smoke and dye test ... This identified one property where the sewer outlet was incorrectly connected to the stormwater system.
"Unfortunately, because the source of the sewage is from a private drain, the council has limited scope to resolve the contamination immediately. The council has discussed the problem with the property owner, requiring that corrective work be undertaken urgently. This has been followed up in writing."
In the meantime, Far North Waters was doing all it could to contain the sewage, he said.
"Fortunately, the total volume of sewage escaping is small and is heavily diluted by stormwater."
The council later admitted the first complaint was in 2020.
At that time, however, an inspection found no sign of sewage.
The incorrect connection was picked up this year when another inspection found traces of toilet tissue, Finch said.
The council had yet to decide if the property owner would be prosecuted.
Northland Regional Council regulatory services manager Colin Dall said the organisation was notified of a sewage discharge on January 27.
It informed the district council the same day and carried out a visual inspection of the stormwater drain in early March, which didn't reveal the source of the sewage.
Dye testing by a district council contractor on April 12 revealed it came from an incorrectly connected property.
If repairs were not effected shortly both councils could take enforcement action to stop the sewage discharge, Dall said.
The district council said water from the Paihia-Ōpua-Waitangi town supply was still safe.
Infrastructure operations manager Glenn Rainham said the water was treated with anti-bacterial UV and chlorine, as required under the national Drinking Water Standards.
It was also tested daily for pH (acidity) and turbidity.
"Together these measures ensure that raw water taken from the Waitangi River is safe to drink," he said.
Regular tests were also conducted for the presence of E.coli (a bacteria associated with faeces).
If the water was found to breach standards the council had to notify the national water services regulator and, if there was a community health concern, the Northland District Health Board.
There had been no such incidents affecting the Paihia-Ōpua-Waitangi supply, he said.
As of Tuesday this week, when the Advocate visited, toilet paper, faeces and what appeared to be a wet wipe were still visible at the outflow.
There was no sign of any measures to stop waste entering the river.
The Advocate understands the dye test initially identified the wrong house, which added to delays in addressing the problem.
It is not known whether the connection to the stormwater drain was deliberate or accidental.
For privacy reasons the council won't say which house is involved.
Under the Health Act 1956 local authorities have the power, "if satisfied that any nuisance, or any condition likely to be injurious to health or offensive, exists in the district, to cause all proper steps to be taken to secure the abatement of the nuisance or the removal of the condition."