Understanding the importance of underground assets

Worker Surveying

Modern life as we know it would be disturbed significantly if our underground assets that deliver our gas, electricity, water, internet – just to name a few were damaged and out of action.

Think about it, no hot water, no cooking, no google, no money from the ATM. Our lives are completely dependent on protection of these assets and we can’t even see them.

Over time, the number of underground assets has increased as our society advances and technology evolves. To help those who need to identify or work on underground assets the colour coding system was adapted.

Underground utility colour codes are used to differentiate and identify underground utilities to protect it from damage during excavation. There are different types of utilities and in order to tell them apart coloured lines, flags or sometimes both are used. They help mark the location and indicate the type of utility that is buried underground.

Why are Underground Utility Colour Codes Important?

The Code of Practice introduced by the Health and Safety Authority states that..

‘The aim of the Code of Practice is to improve the level of safety with which excavation work is carried out. In particular, it aims to reduce the incidence of damage to underground services and in doing so to minimise risk to personnel who are involved in this work.

The Code of Practice is intended to provide practical guidance to utility/service providers, clients, designers, planners, project supervisors (both design process and construction stage), contractors, safety representatives and any personnel who are involved in work where there is a risk from underground services.’

Failure to identify underground services correctly can cause accidents. Correct identification may prove difficult as the utility/service providers may have used a wide variety of materials and colours over a number of years. It is important to remember that colours may appear differently under poor or artificial lighting. In addition, ducts may well contain any one of a number of services, irrespective of the type or colour of the duct

As a guiding principle, the national colour coding system for underground utilities are

REDElectric power lines, conduit and cables
ORANGETelecommunication, alarm or signal lines
YELLOWGas, oil, steam, petroleum, or other flammable material.
GREENSewage and drain lines.
BLUEDrinking water
PURPLEReclaimed water, irrigation, and slurry lines
PINKTemporary survey markings, unknown/unidentified facilities
WHITEProposed excavation limits or route


Owners of underground assets have millions of dollars sitting beneath our feet. They are regulated to keep an accurate identification system of all assets they own. They are also responsible for the maintenance of these assets.

Every individual who is involved in the design or building process in Australia has access to services that ensure protection of people, property and the underground assets that help provide a modern society with the services that keep us comfortable and part of the modern world.

It is everyone’s responsibility to be guided by the regulations and keep safety front of mind.

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