Water use, sustainability, and efficiency by choosing quality systems and materials, and providing environmentally friendly solutions.
With wastewater, the overriding consideration is building users’ health and safety.
Most buildings will connect to a town or city sewerage system. However, there are options for on-site disposal that can be used when there is no mains sewerage available. Some wastewater can also be recycled to reduce building water use.
In this section, we describe best practice options for installing standard wastewater systems. We also describe other options such as greywater recycling.
While recycling greywater has benefits, maintenance is required to keep these recycling systems operating properly. Specific maintenance tasks should be pointed out to clients considering this option, without discouraging them, before they make a final decision.
Installation of sanitary plumbing and drainage systems in New Zealand must be in accordance with NZ Building Code clause G13 Foul water or AS/NZS 3500 Plumbing and drainage.
The key objectives of Clause G13 are to safeguard people from:
- illness due to infection or contamination as a result of personal hygiene activities
- loss of amenity due to the presence of unpleasant odours or the accumulation of offensive matter resulting from sewage disposal.
To do this, sanitary plumbing and drainage must be designed to carry discharges away so that they:
- do not cause nuisance or health risk
- prevent foul air and gases that are generated in sewers, drains and plumbing systems from entering buildings
- minimise the risk of blockage
- minimise noise generated by the flow within the system
- allow for access and cleaning
- are durable
Acceptable Solution G13/AS1 applies to above-ground non-pressurised sanitary plumbing (i.e. pipes, fixtures and fittings above ground). Acceptable Solution G13/AS2 applies to drainage (i.e. below ground pipework).
Sanitary plumbing and drainage falls under the key plumbing standard AS/NZS 3500 Plumbing and Drainage. A new version of the standard was published in mid-2018 but is getting a long rollout – the older version must still be used until the new version can be referenced.
Updated: 23 July 2018