Welcome to Unitcare

Maintenance: Plumbing – Drains

In this chapter we explain plumbing terms in relation to drains, along with problems commonly encountered. We also look at preventative maintenance.

Legislation – Strata Titles Act

Click on Legislation above, to view strata title legislation and hints.

Legislation – Community Titles Act

Click on Legislation above, to view strata title legislation and hints.

What does this mean?

Services that do not serve a single unit or lot, are the Corporation’s common property, this includes the sewerage disposal.

The pipes shown in yellow are the owner’s to maintain.

Unit 4 has a sewer vent pipe that serves the common sewer. This means that the branch serving unit 4 is common; unlike those which serve units 1 to 3.

Plumbing consists of two distinct systems: supply,(bringing fresh water in) and drainage, (taking wastewater out). The pipes in black are drains. The vent pipes allow the drains to breathe consequently preventing siphoning of trap water, such as in toilets. If not vented then sewer smells will enter the unit.

The diagram below shows a domestic sewer and connection to street.

The picture below shows a sewer stack on the outside of a three storey group of units. The stack branches to serve each unit, and passes through the roof to vent the sewer.

The picture below is of a sewer inspection cover commonly used about units. This is a new cover where the plumber has raised an inspection point to enable cleaning of the common sewer.

Common Problems

  • Gurgling toilet – this can be the result of a blocked sewer. This is often caused by tree roots but can be the result of objects accidentally or deliberately put in the sewer.
  • Old earthenware sewerage pipe collapses – the pipe work often needs replacing with PVC. Sometimes, this can be undertaken in sections rather than replacing the entire sewer.
  • Blocked trap under sink.

The following picture shows a licensed plumber using a drain cleaning machine to clear a blocked sewer. This is a common method for clearing sewers however high-pressure water cleaning can be useful in some cases.

Sewerage pipe video inspection

Persistent sewerage pipe blockages can warrant a video inspection of the sewer system. The following is an example of a video inspection of a sewerage pipe suffering from tree root infiltration.

Click on image to go to video

This video may be useful in understanding some of the problems related to tree roots in sewers & stormwater drains.

The camera inspections can cost around $400 and are worthwhile when the cause of blockages is difficult to treat or pin down.

Video camera inspections can pinpoint problems like these:

  • Broken, cracked or collapsed pipe — damaged pipes requiring repair or replacement.
  • Offset pipe — sewerage pipes have become misaligned due to shifting soil, frozen ground, settling, etc.
  • Blockage — grease buildup or a foreign object is restricting or prohibiting proper flow and/or cleaning of the line.
  • Corrosion — the pipe has deteriorated and/or broken, causing sections to collapse and restrict water flow.
  • Bellied pipe — a section of the pipe has sunk due to ground or soil conditions, creating a valley that collects paper and waste.
  • Leaking joints — the seals between pipes has broken, allowing water to escape into the area surrounding the pipe.
  • Root infiltration — tree or shrub roots have invaded the sewerage pipe, preventing normal cleaning, and/or roots have damaged the pipe.
  • Off-grade pipe — existing pipes are constructed of substandard or outdated material that may have deteriorated or corroded.

Preventative maintenance

Old sewerage pipes that are subject to tree root infiltration

  • 6 monthly sewer clean
  • flooding sewer with copper sulphate

Talk to your local licenced plumber about the options.


The following tools may assist in the maintenance of your groups.

Video – clearing a blocked sink drain

Click on image to go to video

Sewers & tree plantings

Click on picture for printable version