Sewer connections & junctions

Here you will find information about applying for sewer conversions and sewer junctions and also reporting lost ones.

Converting from septic to sewer?

You should engage a licensed plumber to connect your property to our wastewater system. Before converting from a septic tank to a wastewater connection, contact your local government's environmental health officer, who will advise if you need to decommission your old septic tank and the associated requirements.

How to apply for a sewer conversion / connection

Your plumber applies for a sewer conversion through BuilderNet and completes a 'Sewer conversion application'.

Plumbers wanting to connect to Water Corporation's wastewater system must also submit the necessary documentation to the Plumbers Licensing Board prior to carrying out the work.

Upon completion of the plumbing work, your plumber will be required to submit a 'Plumbing diagram' to the Building Commission.

How much will it cost?

Please refer to the Sewer service fees page for our current sewer connection fee.

How to apply for a sewer junction

You can apply for a sewer junction to be 'cut in' through BuilderNet by completing a 'Sewer application'.

How much will it cost?

Please refer to our Sewer service fees page for the cost of cutting in a sewer junction.

Submit your application now

When would I require a new sewer junction?

Generally if a sewer main passes a property, a sewer junction will already exist, however there are some instances where this is not the case, therefore if it is viable, a request for a new sewer junction may be approved.

In two-lot strata schemes we encourage separate junctions to avoid potential disputes if the shared line is damaged or there is a blockage.

When existing plumbing needs to be relocated to within 600mm of the property boundary to reduce the chances of it being impacted by building activity, a second sewer junction may need to be cut in.

Typical sewer connection for strata lots

Typical sewer connection requirements for stratas diagram

How to apply for a sewer junction

You can apply for a sewer junction to be 'cut in' through BuilderNet by completing a 'Sewer Application'.

Alternatively, you can complete our Sewer junction application form and forward it to:

Post: Building Services, PO Box 100, Leederville WA 6902


Fax: (08) 9420 2585

How much will it cost?   

 Please refer to our Sewer service fees page for information about the cost of cutting in a new sewer junction.

What if I can't find an existing sewer junction?

When locating a sewer junction, you may need to excavate at least 1 metre either side of the junction position and 600mm deeper than the depth shown on the e-plan.

If you still have been unable to locate it, please report the lost junction to us on 13 13 95. When making the report, you will need to have current approval to connect to the sewer and the name of the licensed plumber responsible for the site.

How to report a lost junction

Lost junction reports must be made by a licensed plumber, who can confirm that the above instructions have been followed prior to making the report. If a junction is subsequently located within the above limits, we may seek to recover our costs from the licensed plumber responsible for the site.

What you will need to do:

  • Safely secure the excavation site, pending resolution.
  • If the site cannot be secured, the excavation area will need to be backfilled. Please take photos of the site before backfilling, to support your lost sewer junction report.

We will let you know a resolution date when you make the report.

How to find the sewer connection point

We will provide copies of the sewer e-plan with your sewer junction application approval, to help you find the sewer connection point. To prevent damage it is important to confirm the location and depth of the sewer connection point before starting work, in particular if the connection is long or 'in and up' measurements have been provided on the e-plan.

Providing as constructed information for a new cut in junction

Please follow the steps below when providing as constructed information for a new sewer junction.

  • A licensed plumber needs to excavate the sewer main, ensuring it is safe for entry.
  • We install off take junction to the sewer main.
  • We measure off take junction position relative to the downstream access chamber or maintenance shaft. If we cannot obtain a measurement, the off take junction will be located relative to the property boundaries.
  • We record the measurements on a minor works as constructed – sewer work sheet.
  • If required, a licensed plumber constructs an extension or “ins” and “ups” and records the measurements on our As constructed sewer form. Refer to our guide on How to provide as constructed information.
  • Licensed plumber submits the completed form to Water Corporation.