How to find plumbing plans for your house

Request the property file from your council

The property file is the collection of documents lodged for your address over the years - consents, inspections and as-built drawings. It is where plumbing and drainage plans live.

Ask for the property file specifically, not a LIM. A LIM is a summary report; the property file is the underlying documents, and only the property file contains the drawings.

Find the as-builts in the file

Property files can run to hundreds of pages. The drawings you want are usually attached to the building consent for the original construction, or to any later consent for a bathroom, kitchen or extension.

Cross-check against what you can see

Walk the house and section against the drawing. Gully traps, inspection points, vent pipes, external taps and the meter or toby position all tell you whether the drawing still matches reality.

Renovations frequently move pipework without anyone updating the record.

If nothing is on file, trace it

Older houses often have no as-built at all. A plumber or drainlayer can trace the runs with a camera and sonde, which is far cheaper than finding them with a digger.

Lodge your own as-built when you alter it

If you are the one doing the work, make sure the updated drawing goes back into the property file. It is the cheapest favour you can do the next owner, and the next person holding a spade.