Wastewater is water that households and businesses wash away. It passes through the sewerage system. The main types of wastewater are: 

  • greywater – from showers, baths, hand basins, washing machines, laundry troughs and kitchens 
  • blackwater – for example, toilet waste  
  • sewage – a combination of greywater and blackwater 
  • industrial wastewater – includes all waterborne waste except sewage.  

How wastewater can impact human health and the environment

Wastewater can contain micro-organisms, bacteria and viruses that can cause disease. Contact with dangerous bacteria can cause skin, eye and nose infections or gastroenteritis (gastro or upset stomach).  

Wastewater can also contain pollutants, including:

  • Sediment – soil, sand and other particles that can build up in waterways 
  • Micro-organisms – organisms we can’t see that can spread disease (for example, bacteria). 
  • Heavy metals – including industrial waste elements. Also includes elements naturally present in the environment that can be harmful in large amounts. 

All these can impact water quality and harm plants and animals that depend on water. Water with high pH levels (acidity) can also give people skin, eye and nose infections.

Read more about wastewater

Reviewed 15 September 2020