Avenues' residents are sick of dealing with sewage overflow on or in their properties and it looks like council has listened to their concerns. Photo / Tania Whyte
The Whangārei District Council is considering a seven-figure investment into wastewater infrastructure in the Avenues suburb after residents complained about regular sewage overflows in their homes and on their properties.
On July 28, Kauika Rd resident Robyn Gow sent an email to the council which highlighted nine properties along Kauika Rd and Third Ave that had experienced regular issues with sewage spewing from their gully traps - a basin in the ground that receives a property's piped wastewater - and even from toilets and showers inside their homes.
Three days later, the Northern Advocate spoke with Whangārei District Council waste and drainage manager Simon Charles to discuss the residents' concerns. The following morning, the Advocate received an email from the council saying Gow's email had been received and "the matter is under investigation with the intention to identify causes and remedies".
On August 3, Charles confirmed an approximate million-dollar upgrade into the Avenues suburb's sewage infrastructure was being seriously considered. However, he stressed implementation of any upgrade was subject to many factors including engineering feasibility, prioritisation and funding.
It comes after Charles denied the council knew sewage overflow was a widespread issue in that area, despite residents claiming they had complained to the council about the issue for almost a decade and the council commissioning a report into stormwater infiltration in the wider Woodhill area late last year.
The issue for the area was evident on July 17-18 when 200mm of rain fell in Whangārei in seven hours. During heavy rain, wastewater systems can be overloaded by stormwater - a process known as stormwater infiltration - which forces sewage and stormwater back up properties' pipes from the pressure.
Multiple Avenues residents told the Northern Advocate that, during the rainfall, sewage and stormwater continuously burst from their gully traps and even overflowed from their toilets and showers.
One of the hardest-hit properties was that of Robyn Gow and husband Doug. The bottom floor of their Kauika Rd home was flooded, forcing the couple to rip out all the damaged carpet from that floor.
It also spilled from the gully trap, leaving bits of excrement and toilet paper strewn across the lawn.
Doug Gow, who had lived at the property since 1977, said sewage overflow had been an issue at the property for about 10 years, occurring every two to three years.
While he was encouraged to hear the council was looking into upgrade options, Gow said the problem would only get worse if council didn't intervene as the suburb's population was growing, putting more strain on its wastewater system.
"[A] permanent [solution] is the only real answer as far as I'm concerned," he said.
"What I don't want to have to do is, every year or three, to pull carpets out of the house which is a major issue."
Gow said he had called in to complain to council about sewage overflow a couple of times. Charles said council records showed no calls had been logged from the Gows' address.
Karen, another Kauika Rd resident, said sewage overflow had occurred at her property at least eight times in the past eight years - once while she was in the shower.
"At one stage, my toilet, my shower and my kitchen sink were getting all sorts of crap coming up through the pipes," she said.
Karen was from one of three properties on Kauika Rd which council records showed were linked to nine reports to council of sewage overflow. In all nine cases, council deemed the cause had not been stormwater infiltration.
However, Karen said every instance of sewage overflow coincided with a heavy rain event and the council needed to upgrade the area's wastewater system.
"We're not asking for a lot, it's kind of scary whenever it rains heavy because you know damn well that you're going to get the crap back up through the lines."
Shelley Stringfellow, a Kauika Rd resident of 10 years, said sewage overflow had been an issue for her for about eight years, occurring about four to five times a year.
While she had never had sewage overflow in her home, Stringfellow said she was sick of having it spill out from her gully trap onto her property when it rained hard.
"It doesn't have to be constant heavy rain for it to happen, it can be just a constant couple of hours of heavy rain and that causes overflow into backyard.
"We are at the point where we are over it and we haven't had action from the council."
During the heaviest part of the July 17-18 rainfall, Stringfellow said sewage was blowing out of her gully trap a metre high and over two metres wide, continuing to spill out until the Saturday morning.
In a heavy rain event in 2014, similar overflow occurred on Stringfellow's property and upon notifying the council, contractors were sent to remove the excrement and sanitise the area - a job logged in the council's records.
David Procter, who has lived on Third Ave for eight years, said sewage overflow out of his gully trap had occurred at least three times.
Similar to Stringfellow, council contractors were sent to Procter's home after the 2014 rainfall to clean up overflow from his gully trap - a job also logged in council records.
Procter said any effort to upgrade the area's wastewater system would be worthwhile if it reduced overflow incidents.
"It's a terrible thing, it's awful. I'm pretty unhappy about it," he said.
In a Water New Zealand infiltration and inflow control manual, it said about half of the removable stormwater infiltration into wastewater systems came from private properties, through measures such as non-compliant downpipes feeding stormwater into a gully trap and low-lying gully traps.
Charles said the other half would come from flaws in the public system, such as old piping or faulty manhole covers.
In the council's Woodhill stormwater infiltration study, which assessed 431 properties, it found 247 (57 per cent) were fully compliant, 85 would contribute to infiltration in severe rain events, 35 would contribute to infiltration in most rain events and six would contribute to infiltration in every rain event and needed immediate remedy.
For properties which had experienced overflow in the home, Charles said he was confident there would be some aspect of non-compliance involved.
However, Charles said regular gully trap overflows were not acceptable and indicated the need for an upgrade.
"[It] is a public health risk and it's unsanitary so it shouldn't be happening, so that's what we want to try and eradicate."
Charles said an upgrade to the Avenues suburb wastewater system had been investigated so suddenly because there was a chance it could be done alongside the already-funded Maunu Rd wastewater upgrade project, work on which is set to begin in 2022.
"We've got capacity issues all over the place but we are now aware of these [Avenues] issues, so it makes sense to do it at the same time and address both issues," he said.
Charles speculated two options could be putting in a larger main pipe down Kauika Rd and connecting it with the new Maunu Rd pipe, or to put a new pipe down First Ave and divert any wastewater coming from higher in the catchment such as from Wilson Ave.
Should the upgrade not go ahead, Charles said the next best option was for residents to fit a non-return valve, also known as a flap valve, at the point where their property's wastewater pipe joined the public line - stopping any material from coming back up through the property's pipe.
Priced at about $2000 depending on excavation, the cost of a non-return valve was not paid for or subsidised by the council in accordance with its wastewater bylaw.
Given Water New Zealand deemed issues causing stormwater infiltration came from both public and private systems, all residents the Northern Advocate spoke to believed the council should pay for some if not all of the cost of a non-return valve installation.
Charles said if a property owner could prove sewage overflow had been regular issue and it did not relate to non-compliance or blockages, the council would "come to the party" financially. He would not be drawn on whether the council would pay the entire installation cost.
Charles said this reinforced the necessity for residents to inform the council when such issues occurred as it gave the council a better understanding of an issue's severity.