skip to main content

Infiltration and Inflow

Stormwater and wastewater don't mix! They should always be kept separate.


In December 2022, we will be investigating our wastewater and stormwater networks! This is part of a district-wide project to identify where stormwater is getting into the wastewater network.

If stormwater enters the wastewater system, it can flood and put pressure on our systems. This means the sewer can overflow and send wastewater into our environment. Our aim is to reduce the amount of water entering and being discharged from our treatment plants.

Pipevision will be out in Central Hawke’s Bay, investigating gully traps and pipes, looking for damage and defects where stormwater could be finding its way into our wastewater network.

If stormwater enters the wastewater system, it can flood. This causes the sewer to overflow, sending wastewater onto people’s property, and into the environment. This can make people sick and damage aquatic life.


 Stormwater inputs also limit how much our wastewater pipes can hold. This could stall future development in your area.


Stormwater increases the volume of water to treat at the Wastewater Treatment Plant, this can overflow into our rivers and decrease water quality. It also costs more to treat, meaning ratepayers pay more.


We have set aside funding in our Long Term Plan to address this issue. We have also secured Central Government funding from the Three Waters Reform programme for this project.


We are using CCTV cameras to identify any leaking pipes.


Inspecting manholes for any defects.


ManholeManhole with corroded base


Looking at private properties to identify pipes sending stormwater into the wastewater system.

 Stormwater spouting 

Stormwater spouting running into sewer


Fixing leaky assets

When we find a defect, or someone reports an overflow, we are fixing, repairing or replacing pipes and manholes. Our scheduled pipe renewals also play a part in this.

 Fixing leaky assets


Monitoring flows

We are determining where stormwater flows are coming from, and how much is flowing through, allowing us to narrow down sources. Our hydraulic modelling also plays a part in this.

Look at the Stormwater and Wastewater drainage on your property.

Have a look at your gully trap. Is it cracked, broken or too low? Do any pipes connect from the roof?




Report any Stormwater flooding.

Stormwater flooding indicates a failure of the stormwater system and also has the potential to enter the Wastewater system if there are defects nearby.

Stormwater flooding


Report any Sewer backups or overflows.

Sewer backups or overflows are more than just a health risk. They also indicate significant stormwater inflow. Knowledge of where and when these occur can help Council track down the problem

Our contractors, Pipevision, will walk around your house to inspect and take photographs of your stormwater drain pipes, spouting and gully traps.

  • They may pour a safe, non-toxic dye down your stormwater drain. This is to determine connections to the wastewater network.
  • They may send a CCTV camera down your gully trap to identify breakages.
  • They may use a theatrical smoke machine on sewer pipes. You may see ‘smoke’ coming out of your pipes or out of the ground. Please do not be alarmed.


Our contractors are looking for stormwater and wastewater defects ONLY. Nothing else about your property will be reported.

Please treat our contractors with respect. They are people, with families, just like you. Please let us know if there are any dangers on your property, including dogs.

Thank you in advance.

Contact your local plumber or drainlayer. They will be able to fix it for you. Alternatively, contact Council and we can give you advice on how to proceed.

06 857 8060

28-32 Ruataniwha Street Waipawa 4210

P O Box 127 Waipawa 4240


Central Hawke's Bay District Council - Copyright © 2023 Central Hawke's Bay District Council

Disclaimers and Copyright
While every endeavour has been taken by the Central Hawke's Bay District Council to ensure that the information on this website is accurate and up to date, Central Hawke's Bay District Council shall not be liable for any loss suffered through the use, directly or indirectly, of information on this website. Information contained has been assembled in good faith. Some of the information available in this site is from the New Zealand Public domain and supplied by relevant government agencies. Central Hawke's Bay District Council cannot accept any liability for its accuracy or content. Portions of the information and material on this site, including data, pages, documents, online graphics and images are protected by copyright, unless specifically notified to the contrary. Externally sourced information or material is copyright to the respective provider.

© Central Hawke's Bay District Council - / +64 6 857 8060 /