Wastewater system inspection work

We will be inspecting parts of our wastewater network in the City Centre, Arataki, Matapihi, Mount Maunganui/Airport/Omanu, Pyes Pā/Tauriko, Greerton, Matua, Maungatapu, and Pāpāmoa in February-April 2025. Two different types of inspection will be required: manhole assessments in berms and the road corridor, and smoke testing on public and private property.

Why are we doing it?

We are investigating inflow and infiltration, which are the ways that extra water, such as stormwater, groundwater, or seawater, can enter the wastewater network. Inflow occurs when stormwater enters through damaged manhole covers, or other defects on private property. Infiltration happens when groundwater seeps in through buried cracked pipes or faulty joints. 

This extra water can overload the wastewater network, especially during heavy rainfall, leading to potential overflows and makes the treatment plants work harder to keep up. 

By reducing inflow and infiltration, we can lessen the strain on the wastewater treatment plants and create more capacity to handle future city growth. 

Regular flow measurements and data analysis have identified areas with high inflow and infiltration levels that require further investigation.

Addressing these issues now helps ensure a more reliable and efficient wastewater system for the future.

Project timing, locations, and traffic management

Residents, property owners, and businesses on streets where the work will be carried out will receive a letter advising them of the timing of the works and contact details. 

Please note all dates are subject to change due to weather or other unforeseen circumstances.

While works are underway, temporary traffic management will be in place to ensure the safety of our work crews and the community. 

What to expect while works are underway

Manhole assessments

We are investigating groundwater and seawater infiltration into the wastewater network in the City Centre and parts of Pāpāmoa, Mount Maunganui/Airport/Omanu, Greerton, Pyes Pā/Tauriko, Matua, and Maungatapu. Works will occur at night between midnight and 5am. The works will be on berms and the road corridor – no work will take place on private property.

Smoke testing

We are investigating stormwater inflow sources to the wastewater system in Arataki, Greerton and Matapihi. Works will occur during the day. A harmless, odourless smoke will be injected into the system to see if there are any stormwater entry points to the wastewater network. 

Access to the outside of your dwelling(s) in these areas will be required to see where the smoke is being emitted from. Our contractor will check the smoke testing locations prior to testing and will drop a notification in the mailbox advising of the upcoming test only where a manhole is located within the property boundary.

There may be some noise while works take place, and smoke may be present in the area. The smoke is odourless and non-toxic. There will also be traffic management in place where applicable.

FAQs

Will you be coming onto my property?

Manhole assessments will be undertaken by Taonga Water Advisory. For the works in the City Centre, Pāpāmoa, Mount Maunganui/Airport/Omanu, Greerton, Pyes Pā/Tauriko, Matua, and Maungatapu all inspections and tests will be conducted on public property (e.g., manholes in roads or berms), without entering private property. Smoke testing will be undertaken by Downer NZ in Arataki, Greerton, and Matapihi. Our work crews will need to access the outside of your dwelling(s) to see if the odourless and non-toxic smoke is being emitted from any stormwater drainage sources.

Why are you doing the work at night?

The manhole assessment work in the City Centre, Pāpāmoa, Mount Maunganui/Airport/Omanu, Greerton, Pyes Pā/Tauriko, Matua, and Maungatapu will occur between midnight and 5am when there is less sanitary flow from people using sinks, showers, laundries, and toilets. Working during these hours makes checking for seawater or groundwater infiltration easier in these areas.

Will there be any noise?

There could be some minor noise and disruption, but we will try to keep it to a minimum, particularly with the manhole assessment work being undertaken at night in the City Centre, Pāpāmoa, Mount Maunganui/Airport/Omanu, Greerton, Pyes Pā/Tauriko, Matua, and Maungatapu.

What does the smoke testing involve?

Smoke testing involves forcing a dense, non-toxic, and odourless smoke into the wastewater network at a manhole. The smoke fills the wastewater main and any connected pipes (i.e. plumbing within private property) and follows the path of any breaks in pipes to the ground surface. Smoke testing contract staff monitor the locations where smoke escapes the system and is visible above ground and collect data on these locations.

Three or four people will be set up at several manholes covering 8-10 houses per set up, with each set up taking around 30 minutes.

We will inform local emergency services such as Police and Fire and Emergency NZ regarding both types of works well in advance, so they know why people are working in the streets at night or what the source of the smoke is to avoid unnecessary call outs.