How to get drainage plans for your house (NZ)

Ask the council for your property file

The property file holds the documents lodged for your address over the years, including the as-built drainage plan submitted when the house was built or altered. This is the record that shows where the private drains actually run across your section.

Ask for the property file rather than a LIM. A LIM is a summary report written for a purchase decision; the property file is the underlying document set and is where the as-builts live. Most councils accept a request online, and cost and turnaround vary between them.

Request the public network plan separately

Your private drains connect to a public wastewater or stormwater network that the property file will not describe. That plan comes from whoever operates the network for your address - a council in most of the country, or a council-controlled organisation in the larger centres.

Find the right operator in the directory below and use their enquiry or locate-request link.

Read the plan against what you can see

Gully traps, inspection points and manhole lids are the visible evidence of the drainage layout. Walking the section and matching what you can see against the plan is the fastest way to spot a drawing that no longer matches reality.

Where the two disagree, believe the ground, not the drawing.

Verify before excavating

Drainage runs are shallow, brittle and expensive to repair, and older earthenware pipes break with very little provocation. Near a recorded run, expose it by an agreed method - non-invasive detection, hand digging or hydro excavation - rather than putting a machine through it.