Determining the setbacks

Here you will find information about building near sewers and the guidelines and setbacks involved.

Before submitting your building application, you should determine the location of any sewer mains that exist on the property involved.

You will need to determine the material and depth of the sewer main and refer to our Residential guidelines for designers document for the appropriate protection of sewer main information where building or construction activities are carried out in their proximity.

If additional work such as piling, sewer encasement or enclosing sewers is required, the costs involved are the responsibility of the land owner or developer.

Single storey buildings

We refer to the following table which provides the minimum horizontal clearances required between sewer mains and buildings based on the depth of the main and the type of pipe material involved.

  Minimum horizontal clearance (with piles) Horizontal clearance (without piles)
Sewer main depth
All pipe types
1.0–2.0 0.6 1.5 1.52.5 **
2.13.0 0.6 1.5  2.5
3.14.0 1.0 1.52.5 * 2.5
4.15.0 1.0 2.5 2.5
5.1 + 1.5 2.5 + 2.5 +

*Refer to Graph 1 in our Protection of Services Manual for the exact horizontal clearance
**Refer to Graph 3 in our Protection of Services Manual for the exact horizontal clearance.


In most cases, sewer mains located on residential lots are 150mm or 225mm in diameter and are less than 3 metres deep.

  • If the sewer main is Polyvinyl Chloride (PVC), the minimum distance is 0.6 metres from the building to the centre of the sewer with piling, or 1.5 metres without. If the design is double storey, the minimum distance is 2.5 metres without piling.
  • If the sewer main is Vitreous Clay (VC) or Asbestos Cement (AC), the minimum distance is 600mm from the building to the centre of the sewer with piling, or 2.5 metres without.

Below ground swimming pools and spas

The minimum distance is 0.9 metres to the centre of the sewer with piling, or 2.0 metres without, however the clearance distance will vary based on the depth of the pool closest to the sewer main. 

  Minimum horizontal clearance
between sewer main and edge of
proposed pool / spa (with piles)
Horizontal clearance
where no piles are required
(dependent on depth of pool)
Sewer main depth
All pipe types
PVC (metres) Other (metres)
1.02.0 0.9 1.0 1.0
2.13.0 0.9 2.0 2.03.0 **
3.14.0 1.0 2.0 3.0
4.16.0 1.0 2.03.0 * 3.0
6.1 + 1.5 3.0 + 3.0 +

*Refer to Graph P1 in our Protection of Services Manual for exact horizontal clearance
**Refer to Graph P2 in our Protection of Services Manual for exact horizontal clearance.


Piling involves a technique that installs deep foundations for any form of construction work.

There are a variety of different materials that can be used in the process and the choice of materials is important, so that the foundations of the proposed building are supportive.

When building near our sewer mains, it is the responsibility of the certifying structural engineer to design suitable footings and structural support for the proposed works. Our staff will not advise on specific aspects of structural design.

Pile layout diagram

When piling is required, the following must be provided:

  • a pile detail with building plans including the depth and width of pile indicated
  • a site plan showing the position and spacing of the piles
    Note: The pile detail and site plan must both include the date and the signature of the structural engineer, which must be clearly visible.

If you have already checked our guidelines and determined that your proposed structure is close to our services and that further requirements may be involved in order to protect our services, you should review the options below, which are listed in order of priority.

  1. Can you relocate the proposed structure?
  2. Can our pipework be relocated to accommodate your project? Please note this option is only suitable if it is cost effective, does not negatively impact any structures on the adjoining property and has the agreement both land owners.
  3. Is provision for structural support and access required? This may involve replacement or encasement of our pipework, or in some cases the installation of special footings/piles. All efforts should be made to avoid building over our services.

What if an easement is involved?

An easement is a notification on your title deed outlining where restrictions may apply and it may affect the approval of your proposed building depending on the structure type. However, an easement can be built up to or even over, as long as the appropriate setbacks are adhered to.

More information

For more information about protection of services requirements, please email us at or call 13 13 95. 

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