Excavation safety checker

Check the duties for a trench or excavation: whether it is high risk construction work needing a SWMS, when the sides must be supported, notice to the regulator, and the controls every dig needs.

Figures checked 5 November 2026. Free to use, no sign-in.

Victoria and Western Australia have their own Acts; the tool switches to them.

Is it a trench?

Longer than it is wide, as opposed to a pit, shaft or bulk dig.

The work

Is it construction work?
Is it on or near gas mains, chemical or fuel lines, or live electrical services?
Will powered mobile plant (excavators, loaders, trucks) move in the area?

Excavation duties

High risk construction work

SWMS required

Construction work involving a trench or shaft deeper than 1.5 metres, and an area where powered mobile plant moves is high risk construction work.

Trench support

A trench 1.5 metres or deeper must have all its sides supported by shoring, benching or battering, unless a geotechnical engineer advises in writing that the sides are safe from collapse, and the area must be secured from unauthorised access (r 306).

Controls for every excavation

  • Before digging, the person in control of the site must get current information on underground services and give it to whoever does the excavation (r 304). A free Before You Dig Australia enquiry gets the asset owners’ plans.
  • Keep spoil, plant, vehicles and materials back from the edge so they don’t load the walls or fall in.
  • Provide a safe way in and out, such as a secured ladder or ramp close to where people are working.
  • Barricade or cover the excavation so people and vehicles can’t fall in, and keep unauthorised people out.
  • Have it checked by a competent person before each shift and after rain or anything else that could affect stability.
  • Plan for airborne contaminants and low oxygen in deeper or enclosed excavations.
  • Unsure answers never count as a yes. They are listed as things to confirm.
  • Source: r 291 and r 304–306 of the Work Health and Safety Regulation 2025 (NSW).

General information, not legal or engineering advice. Ground conditions decide the controls: get a competent person to assess the site.

How this works

WHS Regulations (all states and territories except Victoria, plus Comcare): r 304 requires underground services information before digging, r 305 sets the risks to manage (falling in, collapse, falling objects, airborne contaminants), and r 306 requires a trench at least 1.5 metres deep to be secured and its sides supported unless a geotechnical engineer advises otherwise in writing. r 291 makes a trench or shaft deeper than 1.5 metres high risk construction work.

Victoria: the OHS Regulations 2017 list the same high risk triggers (r 322), require emergency procedures where someone could be engulfed (r 331), and require written notice to WorkSafe at least 3 days before construction excavation work (r 355).

Unsure answers never count as a yes.

Legal basis

Checked against these sources on 5 November 2026. Spotted a figure that looks wrong? Tell us.

Questions

When does a trench need shoring?

Under the model WHS Regulations, a trench at least 1.5 metres deep must have all sides supported by shoring, benching or battering unless a geotechnical engineer advises in writing that the sides are safe from collapse. Victoria’s regulations don’t set a depth rule; the collapse risk is controlled under the general order of controls, with guidance in WorkSafe Victoria’s compliance code.

Is every excavation high risk construction work?

No. In construction work it is high risk if it involves a trench or shaft deeper than 1.5 metres or a tunnel, work near gas, chemical, fuel or live electrical services, or an area where powered mobile plant moves. Any one of these means a SWMS is needed.

Do I have to use Before You Dig Australia?

The regulations require the person in control of the site to get current information about underground services before excavation starts. A free Before You Dig Australia enquiry is the standard way to get asset owners’ plans, but not every asset owner is a member, so confirm locations on site.

Do I need to tell the regulator before digging?

In Victoria, yes for construction excavation work: notify WorkSafe in writing at least 3 days before work on a trench deeper than 1.5 metres, a shaft deeper than 2 metres or a tunnel, unless an exclusion applies. Elsewhere, the excavation regulations covered here have no advance notice step, but check with your regulator whether any other notice applies to your work.

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