Wellington Scoop

Porirua Harbour’s sewage time bomb

RNZ photo by Harry Lock

After sewage spilled into Porirua Harbour three times in the last two weeks, Wellington Water’s chief wastewater advisor has described the situation as “a time bomb.”

Discussing the “fragile”sewage pipeline alongside SH1 that has broken twice, Steve Hutchison told RNZ:

“There may be further breaks in this location, until we can get this long-term fix in; but it’s not a quick fix, it will be months rather than weeks.” He said it could take longer than by the end of the year. “We’re just starting to work through that before we can give any timelines or budget estimates.”

The cost is … thought to be in the millions of dollars – money the Porirua Mayor Anita Baker is assuring residents and businesses will not influence the latest rates rise. “This was not in the budget that we’re doing now, so we’re going to have to redo our budgets for this year and reprioritise things. This was a few years out, not for this year.”

Though two of the sewage spills came from the “fragile” pipe alongside SH1 near Paremata, the third spill came when a cross-harbour pipeline burst last week. The pipeline, usually decommissioned, was activated by Wellington Water to transfer sewage across to the treatment plant at Titahi Bay.

RNZ quoted Ngāti Toa Rangatira’s Treaty and strategic relationships manager Naomi Solomon as saying:

“We’ve always said the utilisation of a cross-harbour pipeline is something that we have been opposed to, and unfortunately in this case it was used and it did break. We haven’t had the discussion about assessing the decision-making process but we’ll definitely have a conversation with them at the most senior levels.”

The iwi placed a two-week rāhui on Te Awarua o Porirua on Saturday, and it could be extended. It is the first time in recent memory a rāhui has been placed over the harbour because of sewage discharges.

“We’re sick of having to deal with wastewater overflows. We’re not happy with the fact that we’re no longer able to collect kaimoana from Te Awaroa o Porirua and that’s the aspiration that we want to get to. Anything that we can do as a community to get in behind restoring the mauri of Te Awarua o Porirua, then that is what our direction is.”

The three recent sewage spills are nothing new. Last year sewage spilled into Porirua Harbour ten times – because the city’s treatment plant is overloaded.

Harbour pollution was acknowledged back in 2018, when then councillor Anita Baker said

“While 150 years of damage takes generations to restore, we won’t be making a dent in our goals if the shareholding councils don’t take significant action, matched with a strong financial investment – very soon. Ngāti Toa Rangatira, residents of Porirua catchment and many others who care about our harbour, will naturally feel frustrated at what is seen to be our slow progress.”

In 2015 there was “a strategy and action plan” for the harbour – the events of recent weeks show that such a plan was too little to make any difference.

Upgrades of sewer networks were mentioned in a council report in 2014 which described various plans aimed to making a healthier harbour.

In 2012 the Porirua council said work was “on track” to clean up the harbour.

But the “time bomb” identified today shows that the various plans were ineffective – too little, and now too late.


  1. Henry Filth, 27. July 2021, 11:51

    It seems that New Zealanders are unable to see a piece of water without an urge to dump some sort of muck into it. Come on, a bond issue to fund a new fit-for-purpose plant isn’t a brand new cutting-edge untried idea.

  2. Jamie, 28. July 2021, 7:43

    And we still want to add thousands of houses to an already struggling waste water network.

  3. Paul, 28. July 2021, 9:34

    Does the current sewage disposal system meet existing industry standards for design capacity and maintenance?

  4. bsmith, 9. August 2021, 11:54

    Did the council for one moment think that opening up Aotea, and building mass housing, wouldn’t have an influence on old pipes?.