Part 5 – Wastewater Drainage

5.13    Requirements for Service Pipe Size and Alignment

• For 1 to 4 dwellings a 100 mm nominal bore service pipeline is adequate.
• For 5 or 6 dwellings the capacity of a 100 mm nominal bore service is only adequate if installed at a grade 1:60 or steeper.
• The service pipeline shall be laid to a public drain as a straight pipeline between boundary inspection fitting and manhole, or between boundary inspection fitting and a wye connection on the wastewater main, or between a boundary inspection fitting and a wye connection on a service pipeline conforming to either of the previously listed variations.
• The  minimum acceptable grade is 1:80 (preferred grade 1:60)
• It shall be no longer than 50 m.
• It must comply generally with the in-roadway alignment guideline, ie where a wastewater pipeline changes location within a street, it shall do so at an angle of 45 degrees or greater.  Where a wastewater pipeline crosses other utility services, it shall do so at an angle of 45 degrees or greater.

More than 6 dwellings (also suitable for 3 or more dwellings) – requires the capacity of a 150 mm nominal bore pipeline. (Refer Section 5.6.)