We have four wastewater treatment plants in our area:

  • Moa Point (Wellington)
  • Seaview (Upper Hutt and Lower Hutt)
  • Porirua 
  • Western (Karori)

Together, they treat about 153 million litres of wastewater on a typical day, using biological and ultraviolet treatment processes. The treated water is discharged to the sea. The sludge resulting from filtration and treatment is de-watered (with this water further treated) and the solid content sent to landfills.

What you can do to protect your wastewater pipes (and save money on plumbing bills)

Only flush the "3 P's" down the loo - pee, poo and paper (toilet paper that is)!

You can help protect your wastewater system and our environment by:

  • Avoiding damaging any public wastewater pipes which pass through your property
  • Ensuring access to these pipes is not restricted if these pipes run through your property
  • Not planting trees or shrubs on your property within 1.5 metres of buried wastewater pipelines
  • Ensuring that gutters and down pipes connect only to stormwater drains. If connected to the wastewater system, sewage overflows can occur
  • Maintaining your wastewater drainage system in good condition
  • Not discharging motor oil, fuels, solvents or highly toxic substances into the wastewater system
  • Not flushing wipes and other non-degradable material down the loo

Not so flushable

Disposable wipes (or any other material) should never be flushed down the toilet. They can block up wastewater pipes - yours and your city's - and can cost you thousands of dollars to get the blockages cleared.

If the wipes manage to make it all the way to the wastewater treatment plant, they end up blocking the screens (which have to be cleared by hand). The picture below shows "ragging" being removed from a screen at the Porirua Wastewater Treatment Plant. "Ragging" is material (usually wet wipes, cloth and other non-biodegradable material) that gets flushed into a wastewater network and has to be removed at the treatment plant - usually by hand.

Consumer has investigated "flushable" wipes. Check out their story here.

You can also check out a Fair Go investigation into "flushable" wipes and blocked pipes.

Ragging at Porirua Wastewater Treatment Plant

"Ragging" being removed at the Porirua Wastewater Treatment Plant


'Wetwipes' are not the only things that get flushed that shouldn't. Sanitary items, diapers, shampoo and conditioner bottle, hand towels, and even technology can enter the wastewater network.

These all can cause major blockages at wastewater pumps and treatment plants. If damage happens to your wastewater pipes within your property boundary it is your responsibility to get is repaired, which could cost you a lot in plumber bills.

Wastewater pump blocked pager

Pager(?) found in blocked pump station in Wellington, April 2018. 

Fatberg clogs London sewer

Ever wondered what happens when household cooking oil and food fat is not disposed of properly? Well wonder no more - check out this Stuff article on a massive Fatberg found under a London street. If you run a food outlet, ensure your trade waste treatment and certificates are up to date - contact info@wellingtonwater.co.nz if you need to know more.