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Waikato District Council - Te Kaunihera aa Takiwaa o Waikato

Wastewater

Our partners at Watercare Services Limited (WSL) manages the wastewater services including collection, treatment and safe disposal on behalf of Waikato District Council.

WSL ensures that reticulated wastewater is disposed in a way that does not cause harm to the public and the environment.

Properties which are outside of the reticulated schemes rely on, on-site wastewater treatment (for example, property owners' septic tanks and commercial or industrial businesses' trade waste systems).

It is vital that on-site wastewater management systems are designed, installed and managed in a manner appropriate to on-site conditions and constraints. If they're not, untreated waste could end up in our environment, affecting it and people as well. 

Water supply and wastewater are two infrastructure considerations you need to consider in relation to obtaining consents when developing land, building or renovating. Find out more in land and property and see the water supply and wastewater forms below for more information.

Wastewater Education

It is important that we take care of our wastewater system and this means that we ONLY flush things that the system can handle - and that is the three p's (pee, poo and paper!)

What is a wastewater overflow?

Wastewater overflow occurs when wastewater (sewage) spills out from gully traps, manholes, engineered overflow points or pump stations. It then flows into back yards or waterways and the sea. 

Overflows are more common in wet weather, but they can happen at any time if caused by blockages. 

What causes a wastewater overflow?

  • Blockages caused by foreign objectives within the network or at pumping stations either in wet or dry weather 
  • Inadequate capacity within the network, relative to the flow being transported – this is normally an issue in wet weather 

  • Failure of key equipment (e.g. pumping stations) or power at key installations (e.g. pumping stations) 

Blocking materials

Wet wipes and cleaning wipes are a significant contributor to blockages. They contain plastic fibre which can clog up pipes and pumps fundamental to the operation of our wastewater treatment plant and network.​ 

The effects or consequences of wastewater overflows

  • They result in the pollution of waterways (streams, rivers and harbour)
  • They contribute to public health issues, if next to people or where they swim
  • They cause a loss of utility for sanitary services for customers 

How to prevent an overflow

Help us improve the quality of our streams and rivers by: 

  • Avoid putting non-flushable items such as rags, wet wipes and nappies in the toilet 
  • Not pouring fat, oils and grease into the sink  
  • Ensure stormwater pipes are not discharging into the wastewater network 

In case of a wastewater overflow, call us on 0800 492 452. 

How to stop stormwater from getting into our wastewater network

What is a cross connection? 

A cross connection is the diversion of stormwater into the wastewater network, or wastewater into the stormwater system. 

Check your gully traps and downpipes: 

Check your gully trap is compliant (such as the example below) to prevent groundwater and stormwater runoff from entering the wastewater network by ensuring: 

  • It is raised off the ground 
  • Is covered by a grate  
gully trap diagram

Check your downpipes are correctly installed by ensuring: 

  • It is separate from the gully trap
  • Connects to the stormwater pipes on your property 

A common source of cross connections is a downpipe diverted into the gully trap. It is your responsibility to make sure your drainage pipes connect to the right system. If your downpipes or gully traps are non-compliant or damaged, you need to get in touch with a qualified plumber to avoid causing an overflow.

What is the difference between wet-weather and dry-weather overflows?

Wet-weather overflows

What is it? 

In heavy rain, the volume of stormwater draining from roofs and roads can exceed the capacity of our pipes. Diluted wastewater can overflow into private properties and the wider environment. 

What is it caused by? 

Stormwater can enter the wastewater system directly through things such as low lying house gully traps, stormwater down pipes accidentally connected to the wastewater system, and manhole vents. Groundwater can enter through cracks in underground private or public pipes.  

What needs to be done? 

You can help by ensuring your stormwater downpipe does not directly connect to your gully trap.

Council has a continuing programme of work to reduce wastewater overflows, by reducing the amount of inflow and infiltration into its wastewater network as well as increasing the capacity of the network.

Dry-weather overflows

What is it?

Dry weather overflows are usually caused by something blocking the wastewater mains which cause wastewater to back-up behind the blockage and fill the pipes and overflow out of the manholes upstream of the blockage.  

What is it caused by?

Fat, food scraps, or rubbish such as wet wipes can build up in a pipe. Over time they form large clumps that block the pipe and cause sewage to flow onto your property or on the street.

What need to be done?

You can help by avoiding flushing the items listed under ‘blocking material’ below.

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