Who is responsible for a blocked sewer, me or the water authority?

Every water authority publishes a boundary. On one side, the property owner owns and maintains the drain. On the other, the authority does. The exact point varies, and in some networks the authority maintains part of the line within the property, so the general rule is a starting point rather than an answer for your address.

Before you call anyone

1. 1Check whether neighbours are affected. Several properties backing up at once points at the main, which makes it the authority's problem and usually free to you.
2. 2Look at the overflow gully outside. It is designed to release before waste backs up inside, and if it is flowing, the blockage is downstream of it.
3. 3Note whether it is all fixtures or one. One slow fixture is a local blockage, not a sewer problem.
4. 4Call the water authority first if there is any chance it is theirs. Many attend at no charge and will tell you if it is on your side.

The usual cause

In older Australian suburbs with clay pipes and mature trees, roots are the dominant cause. A jetting clears it and the roots return, so the real question after two or three clears is whether the section should be relined or replaced. A camera inspection is what turns that from a guess into a decision.