Design standards

The information in this section will help designers and architects understand and implement our protection of services requirements when working near our water, sewer and drainage services.

You need to refer to our Protection of Services Manual when designing and planning your construction project. Following these guidelines will help you to ensure your works do not impact our water, sewer and drainage services.

These guidelines below identify our minimum requirements for the support of structures built near or over our services. They will help you to develop an appropriate design that protects against:

  • unnecessary restriction of access to our water, sewer and drainage services
  • physical damage to our water, sewer and drainage services
  • physical damage to structures on the property
  • structural load on water, sewer and drainage services
  • costs for future maintenance or emergency repair to those services.

What you need to consider

Please follow this checklist when starting the design process to help you determine if further action to protect our services is required.

  • Is protection against structural loads required?
  • What is the settlement and shearing effect of structures built near or over our services?
  • Cantilevered footings should be designed to allow removal of soil within the zone of influence. Soil anchors should not be placed within the zone of influence.
  • Soil and ground characteristics.
  • Potential for natural or accidental flooding of the structure and any need for:
    • drainage of service access tunnels or enclosures provided to protect our services
    • anchoring of the service to prevent flotation as a result of flooding.
  • Permanency of the affected components of the building or structure and whether it is intended for habitable or continuous use.
  • The possibility of impacting our services as work progresses.
  • Impact (dynamic) loads as work progresses, such as vehicle loads, pile driving and site compaction.
  • Method of carrying-out work, such as excavated access ramps, soil stockpiles restricting access.
  • Will sufficient headroom be maintained at all times over any of our services?
  • Access to access chambers, inspection shafts and inspection openings, including:
    • we need to be able to access our services at all times via the property where any of our access chambers, inspection shafts or inspection openings are located
    • an access way of at least 900mm width is required.
  • No part of any structure or installed equipment can be within a zone extending 1.5 m horizontally from the:
    • centre-line of our sewer inspection shaft, rising shaft or inspection opening
    • centre-line at any access chamber.
  • A minimum 2.4m clearance must be maintained where a sewer passes between structures on a single lot.
  • Will you need to amend access chamber or inspection shaft levels, or maintain required soil cover over pipes, where earthworks are required? Access chambers and inspection shafts need to be brought to finished ground level with appropriate protective covers if in a vehicle traffic area.

What are the guidelines for the protection of services?

If the proposed structure requires piling/special footings due to the proximity of our services, you will need to engage a structural engineer. Please refer to our guidelines to determine if your project requires additional work to be carried out in order protect our services.

Calculating the required footing depths, will determine whether the proposed development requires additional protection of our nearby gravity pipes:

(a) Determine the shortest distance between the centre-line of our sewer (whether or not it is concrete encased) and the:

  • outer leaf of wall cladding for single storey buildings with standard footings
  • edge of the footing for other developments.

The centre-line of the sewer is indicated on our as constructed plans.

(b) Determine the vertical depth of our sewer below the:

  • finished ground surface level, for single storey buildings with standard footings
  • base of the proposed footings, for other developments.

The level of the sewer is its invert level to Australian Height Datum (AHD).

(c) If the vertical depth is more than the depth determined by (b), additional protection of our nearby services will be required:

  • for 150mm and 225mm pipes, the distance determined in (a) minus 600mm
  • for 300mm to 600mm pipes, the distance determined in (a) minus 1000mm.

For cases involving larger sewers and other soil conditions, an assessment by our engineering staff is required.

Additional protection will also be required where at least the following vertical clearance between the finished ground level above the service and the underside of any slab (or other part of the structure) is not maintained by the proposed design:

  • for 150mm to 300mm pipes, 2.4m
  • for 375mm to 600mm pipes, 2.8m.

Building over larger pipes is not allowed.

Where the proposed work falls within the zone of influence special footings/piles and/or access to our service may need to be provided. Footings/piles are to be taken at least 300mm below the zone of influence or to refusal in unexcavated solid rock.

Where the proposed work falls within the zone of construction, but not within the zone of influence, special footings/piles are not required.

  • Repositioning may be possible, alternatively vacuum pipes should be protected in the same way as 150mm–300mm gravity pipes, as described above.
  • If vacuum pipes are in proximity to the proposed building or construction work please contact us on building.services@watercorporation.com.au or call 13 13 95.

Calculating the proximity of pressure pipes to your proposed work will determine if additional work to protect our services is required:

Determine whether the proposed building or construction work is within proximity:

  • Proximity in this case is defined as within 1.5m from the centre-line of the pipe (whether or not it is concrete encased).

The centre-line of the pipe is indicated on our as constructed plans.

Building proposals will be referred to our asset management staff where the proposed building or construction work is:

  • within proximity
  • within 2m of a pressure main located on private property.

Where further action to protect our services is required due to the proposed building or building alteration being in proximity to our service:

  • no building works, other than exempted works, will be permitted above the level of the pressure main and within an area extending horizontally 1m either side of the centre-line of the pressure main
  • building works, other than exempted works, within the balance of the zone of influence will only be permitted in exceptional circumstances – in such cases, the structural load from the building must be taken to a continuous strip footing with its base at a depth of at least 300mm below the pipe invert; this must support a continuous structural wall
  • building works within the zone of construction, but not within the zone of influence, are permitted without special footings.

Where any open stormwater drain or compensating basin operated by us is located (other than in a dedicated reserve), no building is permitted within 5m of either the:

  • top of the bank of the drain or compensating basin
  • floodway (or waterway) of a 1–in–10 year storm event.

To determine the requirements associated to the protection of our assets, please contact us on building.services@watercorporation.com.au or call 13 13 95.

Private building within our reserve is not permitted, however building within an easement may be permitted if the requirements for protecting our services have been met.

For strata developments, if you are building onto an easement you will need to surrender the affected portion of the easement at the strata titling stage.

The requirements protecting our services for the redevelopment of existing buildings, where only the building shell or portion of the building shell remains, are usually negotiated with the owner or developer.

Where it is not possible to either amend the building proposal or relocate any of our services, any requirements for the protection of our services that are not covered in detail by our guidelines must first be confirmed acceptable by us.

Do not build over pressure services

Where it is necessary to build habitable, commercial or industrial buildings, or major structures, over our sewers you will need to provide access tunnels constructed to our guidelines.

Find out more about enclosing sewers in tunnels

Consequences of not following our guidelines

Where a structure has been built and it encroaches on an area that cannot be built on, by law the builder is required to underpin the structure. In some circumstances, we may order for the structure to be removed.

Other buried services

Our Protection of Services guidelines relate only to work near our buried pipelines. Owners of other buried assets have their own requirements. You can obtain plans of all essential community services, including water electricity, gas and communications infrastructure by contacting Dial Before You Dig.

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