Wastewater

Waste water treatment plant

Wastewater is the used water that drains from your sinks, bathroom or toilet.

It flows out of your property via a network of pipes to the wastewater treatment plant on Airport Road where it is treated. After treatment, it is then discharged to sea through the ocean outfall approximately 1.7 km off South Beach.

Separate rural wastewater schemes are operated at Marybank and Mowhanau while Industrial premises are serviced through a controlled discharge regime under trade waste regulations.

Services

We provide the following services:

  • Wastewater connections are provided at property boundaries and the service is available to all connected properties 99% of the time
  • Information to assist with service locations are available on request through the automated BeforeUDig service. On-site assistance can also be requested through Customer Services at 06 3490001
  • Residential properties (except for those in restricted services zones) can discharge an unlimited volume of wastewater, 24 hours per day, seven days per week
  • Industrial wastewater is collected in accordance with individual industry agreements, and the Trade Wastes Bylaw 2018(PDF, 324KB).
  • Complaints/enquiries about service breakdown are responded to within four hours

Caring for our wastewater network

To take care of the network, please only flush toilet paper and human waste down the toilet. Many 'flushable' products don’t break down properly and can cause blockages. Please avoid pouring fat, oil or grease down your kitchen sink.

Also, having your downpipes and gully traps correctly installed can also help to prevent the overflow of stormwater into our wastewater pipes during wet weather. If stormwater gets into wastewater pipes, this can overwhelm our wastewater system, leading to untreated wastewater spilling out from gully traps, manholes, overflow points or pump stations. To protect properties, waterways and beaches we want to keep untreated wastewater entering the wider environment. 

Watch this video about how the wastewater treatment plant works

View this diagram about the wastewater treatment plant(PDF, 206KB)


Blocked sewer pipe or toilet?

If you have a blocked sewer pipe or toilet, it is your responsibility as the property owner to contact a plumber to attend and investigate the cause.  

The plumber is responsible for identifying the blockage's location. If the plumber identifies the blockage is within the council's area of responsibility, they must advise the council – call 06 3490001 (this number is monitored 24/7 – during business hours press 2 to connect to the drainage team who will arrange the authorised contractor to attend).  Any problems inside private property are managed by the property owner.

Where are sewer pipes located?

If your property has had a building consent in the past there may be a drainage plan on file.

Please refer to https://www.whanganui.govt.nz/Property/Property-Information/Request-a-property-file to find out how to request a property file. 


Signs of a main sewer blockage

If it is a mains blockage there may be signs of a manhole overflowing. Contact the council immediately on 06 349 0001 (this number is monitored 24/7 – during business hours press 2 for the drainage and water team).  

What if the sewer blockage within my property is a result of a council tree?

The council will not prune or remove a council tree where its roots are entering a private drain.

More information about council trees can be found here.


What to do once the blockage is cleared

The authorised contractor will advise the plumber to backfill the hole once they have managed to get the service flowing again and carried out any CCTV if required.

Temporary repairs may be done first to restore service. A council drainage representative will instruct the authorised contractor if further works are required.

Who is the authorised contractor?

The water and drainage maintenance contract has been awarded to Veolia Australia and New Zealand Ltd.


What area is the responsibility of the council?

The council is responsible for blockages from the boundary to the sewer main (sewer lateral).

Below are four scenarios. The area in yellow indicates the council's area of responsibility. 

Wastewater pipes - scenario 1

Wastewater pipes - scenario 2

Wastewater pipes - scenario 3

Wastewater pipes - scenario 4

Am I allowed to check manholes?

Under no circumstances are members of the public, plumbers, or drainlayers allowed to lift a manhole lid or enter a manhole. Manholes can be extremely dangerous and have caused numerous fatalities in the past. 


Who is liable for fixing the problem and paying for repairs?

If the blockage is found to be as a result of a blockage within the council’s network, the council will be invoiced. The council is not responsible for either the repairs or the cost of any issues caused by faults on private property.


Information for plumbers

As a plumber it is your responsibility to identify the blockage is within the council’s network and that the site is safe and meets health and safety requirements. 

Call 06 3490001(this number is monitored 24/7 – during business hours press 2 for the drainage and water team).  We will need to know that you have exposed the blockage, the address of the problem and your contact details. You will also need to fill out a blocked drain form(PDF, 226KB) and email it to the council.

Where it isn't possible to expose the pipe at the boundary but the blockage has been identified within the council’s area of responsibility, please contact the drainage team.