It is important for you to check with the Council if you require consent prior to starting any drainage work.
The Council holds drainage plans for most properties in the city as well as the public drainage plans (these drains are usually located in the roading network). Drainage plans can assist you or your registered drain-layer if you want to identify where the drains on a particular property run. At this time the Council charges no fee for drainage plans.
Please see the building forms and guidlines links
Drainage and Sewerage
This site also contains information about blocked drains, septic tanks, stormwater and the city's drainage and sewage systems, water connections, sales and supply.