Wellington Water's chief executive says the Moa Point wastewater treatment plant is not in good shape, with 70% of it flooded and 80% of its equipment damaged.
An equipment failure flooded the site and is sending raw sewage spewing directly into the southern coastline - rather than through a longer pipe, nearly 2km into Cook Strait.
Pat Dougherty said he hoped the long pipe would be fixed by the end of the weekend, but it would likely be months before the plant was fully repaired.
As a water engineer, he said he was used to seeing damaged plants - but he had never seen anything like this.
The priorities would be to get the sludge out of the plant so it did not turn anaerobic and stink, getting a camera in to look at the outfall pipe to understand what caused a back-up into the building, and working to get power on to parts of the building so they can start to use the long outfall, Dougherty said.
Today's inspection showed the damage was "as bad as we feared", he said.
But Dougherty said so long as they managed to get the long outfall pipe operating fairly quickly, the tides would take care of it and he did not expect there would be long-term environmental damage.
People are being urged not to enter the water, collect seafood, or walk their dogs on the beach. Wellington Water said a rāhui (ban) is in place and covers anything the water can touch with the high or low tides.
"While it is in effect, no public activities should be undertaken on or around the beaches on the southern coastline."
"This is my neighbourhood, this is where I take my dog for a walk, and along that coastline is where I spend my time, that's where I go kayaking and swimming."
Wellington Water is taking water samples from a wide area and would deploying divers at the weekend to investigate the condition of the major pipe at the plant that got blocked up.
Cameras would be sent down the beginning of the long outfall pipe and divers would then check the end of it underwater.
Teams were working "as quickly as possible" to divert as much sewage from the short outfall to the long outfall pipe, an update from the company this afternoon said, as well to put screening in pace to remove items like sanitary pads from the wastewater being discharged.
Wellingtonians could expect to see discolouration around the coastline for about a week as teams emptied clarifiers and primary settling tanks to reduce odour.
They could also expect an increase in smell due to the plant being offline and work taking place on site.
"We will do all that we can to mitigate the impacts of odour," the company said.
DOC 'extremely concerned'
Department of Conservation's principal marine science adviser Shane Geange told RNZ's Checkpoint programme today it was "extremely concerned" at the situation.
"From an ecological perspective, raw sewage and wastewater entering a marine environment poses an immediate and serve threat to a wide range of ecological functions and species.
"But I think the primary concern is around the public health concern which Greater Wellington health authorities are actively managing."
Raw sewage carried bacteria, viruses and parasites that could impact sponges, mussels and fish that eat particles in the water, he said.
"They can also accumulate in shell fish which make them unsafe for consumption."
The sewage could also impact penguin and how they regulate their bodies.
Geange said the department was working with the Greater Wellington Regional Council to figure out how far the sewage had spread.
He said the sea water would "rapidly" dilute the sewage, but not enough to destroy contaminates.
Surfers and life savers gutted
Surfers and surf lifesavers are devastated the south coast is off-limits while sewage spews into the sea, worrying it is a return to a time when there were "turds in the waves".
Jamie McCaskill from Wellington Boardriders told RNZ's Morning Report programme today he was gutted.
"We've got a few events coming up, this is a bad time for us ... it's just really not a good time, especially at this time of year."
The worst part was not knowing when the water would be safe, he said, and wants clear communication from Wellington Water about that.
McCaskill worried it would be a return to decades prior before the long outfall pipe was built.
"I've been talking to a few of the legend surfers, and kind of before 1989 there was just ... raw sewage, smells on the rocks, on the wall, surfing in barrels with turds in the waves," he said.
"There were sicknesses, ear infections, skin infections, gastro, so we're just trying to avoid that, that's for sure."
There were no other places nearby to surf, he said.
"We could go to Wainuiomata or over to the Wairarapa - but it's just such a long way. It's a bit of a bummer that we just can't go locally."
Lyall Bay Surf Lifesaving Club chairperson Matt Flannery said his members were as disappointed as the rest of the community.
"We can't use what is a beautiful part of the city. It's really concerning."
The club has had to reschedule this weekend's planned competitions, and it has disrupted members' training for national events.
"We're at the final part of the season where we've got very regular use on the beach, with probably 70 or 80 club members in the water on a daily basis, so that's a fairly big impact," Flannery said.
"It's at a time of the year that we're training for national championships four weeks out, and obviously the uncertainty about when the beach will reopen is of a major concern for us."
That uncertainty made their rejigged training plans "a bit of a guessing game", he said.
Lifeguards would not be patrolling the beach this weekend and a red flag would fly at the club to show the beach is unsafe.
