Water you have used in your home – wastewater, leaves your house through a sewer pipe which connects to other pipes along your street. The wastewater then journeys on to a pump station.
Pump stations are often located at a lower point so that gravity assists in the transporting of water to this point. The wastewater is then pumped to the treatment plant where it is treated to an appropriate standard. You can find out more about what happens at many wastewater treatment plants by checking out this video. One of the products of wastewater treatment is sludge. This is removed and stabilised, dewatered and disposed of or reused.
Once the water has been treated it leaves the treatment plant and is then discharged to either the ocean, a river, onto land or re-used.
Image source: Watercare Services Limited
If your home is not connected to the mains sewer, then you are likely to have some type of on-site wastewater treatment system to treat and dispose of your wastewater. There are many types of on-site wastewater treatment systems – the most common type of system is the septic tank and disposal field.
Image source: New Zealand Water and Wastes Association (NZWWA) and Ministry for the Environment
On-site systems need to be designed and installed correctly and they require regular maintenance to work effectively. If your system fails it will cause a dirty, smelly and potential costly mess. A failing system can put your family’s health at risk and it may also pollute the water in local streams, rivers or wells with pathogens and nutrients that are harmful to humans and the environment.
To learn more about septic tanks and how to look after them see The Story of your Septic Tank System pamphlet (PDF 1.6MB) produced by the New Zealand Water and Waste Association and the Ministry for the Environment. Waitakere City Council and Greater Wellington Regional Council websites also have useful guides.
The Smarter Homes website's sewerage system's overview is a good source of information on choosing and maintaining septic tanks.
For information specific to your local area contact your regional council.
Composting toilets are an alternative to septic tanks. The Smarter Homes website provides information on composting toilets and whether they might be right for you.
