Here's What Those Crazy Markings Spray-Painted All Over Sydney Pavements Mean

Some of the markings on the ground in the Sydney CBD. Photo: Business Insider

In September 2009 someone struck a series of Telstra copper and optical cables on York Street in the Sydney CBD.

Dial Before You Dig state manager Dominic Puiu said the damage cost between $700 million and $800 million, between repair costs and third-party losses.

“Telstra will take you to court, and they will hit you with a bill based on your liability. Then other businesses will come after you,” Puiu said.

If you’ve been wondering why there are multi-coloured squiggle lines sprayed on the pavement in the CBD, this is why.

Considering the density of piping and utilities underground in the city, work that requires excavation needs to be done with care.

These lines are a code which became standardised in Australia last year. If you can understand them, they explain where electricity cables, telecom lines and sewerage pipes lie, as well as a host of other underground hazards.

At the moment, there are so many markings around George Street in Sydney because of Geotechnical tests for a planned light rain line that will go through the CBD.

Markings on the street in the Sydney CBD. Photo: Business Insider

In this photo, the seven white circles indicate telecommunications pipes. The yellow-paint square outline indicates a pit or “cabin,” which can stretch for meters underground. Other markings indicate empty pipes into which telecommunication cables can be retrofitted.

“You can buy optical fibre for around $3 per metre, though telecoms piping can cost between $100 and $1000 to lay,” he said.

“If you’re going to put in three pipes, it’s just as easy to put in six,” as it is so expensive to do it at a later date.

The markings, Puiu said, cannot be read in isolation. While complex, they require other visual references such as landmarks, as well as comprehensive plans to be understood correctly.

The markings — which use a complicated colour, number and symbol code — were only standardised last year, which Puiu says was an important step.

“I’m really happy this work is being done [in the Sydney CBD]. It’s really good to see that care is being taken.”

Qualified worked use ground-penetrating radar to locate objects, and then mark them with the code.

Here’s a quick reference guide, based on the Australian standard.

  • White/C: Communications
  • Green/D: Stormwater/raw water
  • Orange/E: Electricity
  • Red/F: Fire Service
  • Yellow/G: Gas
  • Brown/P: Petroleum products
  • Purple/R: Recycled water
  • Beige: Sewer
  • Pink/U: Unidentified services
  • Blue/W: Water service

This one uses letters to represent utility features:

  • M: Main
  • CM: Communication main
  • WM: Water main
  • OFM: Optical fibre conduit
  • P: Drainage pit
  • H: Electrical house connection
  • HY: Hydrant
  • HV: High voltage electricity
  • MH: Manhole cover
  • H: Sewer house connection

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.