Quick answer: Trenching and excavation work often requires a SWMS. Trenches deeper than 1.5 metres are a direct High Risk Construction Work trigger, but shallower excavation can still require a SWMS where the surrounding risks are high.
Last reviewed: March 2026 by the BlueSafe Technical Team. Reflects current Australian WHS requirements.
Excavation risk is often underestimated because the hole itself is treated as the hazard. In practice, the bigger issue is the full work area: services, spoil piles, plant movements, weather, and the condition of the ground before anyone enters.
At a glance
| Item | Summary |
|---|---|
| SWMS legally required? | Yes |
| Licence required? | Depends on task |
| Main HRCW trigger | #7 trench work deeper than 1.5 metres |
| Typical tasks | Excavation, trenching, shoring, shielding, benching |
| Main SWMS focus | Ground stability, buried services, access, support systems, plant |
| Main risk | Collapse, engulfment, service strike, and plant interaction |
When does excavation need a SWMS?
A SWMS is required for trench work deeper than 1.5 metres and may also be required for other excavation tasks where HRCW conditions exist.
Common trigger situations include:
- trenches deeper than 1.5 metres
- excavation near buried electrical, gas, or water services
- unstable ground or adjacent structures
- heavy plant working close to the edge
- excavation in traffic or public-interface areas
Why depth is not the only issue
| Condition | Why it matters |
|---|---|
| Ground instability | Collapse can happen even in shallower excavations |
| Buried services | Service strikes can create electrical, gas, or flooding hazards |
| Spoil placement | Extra loading near the edge can weaken the trench wall |
| Plant movement | Excavators and vehicles increase collapse and strike risk |
What an excavation SWMS should cover
The SWMS should explain:
- how services are identified before digging
- how the excavation will be opened and staged
- whether shoring, benching, or shielding is used
- how spoil and plant are kept clear of the edge
- how workers enter and exit safely
- what the stop-work triggers are if conditions change
Common trenching failures
The most common failures are:
- digging before confirming services
- leaving spoil too close to the edge
- entering unsupported trenches
- relying on visual inspection only after rain or disturbance
- poor plant separation around the trench
State and territory variations
Excavation duties are broadly similar across WHS jurisdictions, with local regulator guidance shaping the detail.
| Jurisdiction | Regulator | Key note |
|---|---|---|
| NSW | SafeWork NSW | Model WHS framework applies |
| VIC | WorkSafe Victoria | Different legislative framework and local rules |
| QLD | Workplace Health and Safety Queensland | Model WHS framework applies |
| SA | SafeWork SA | Model WHS framework applies |
| WA | WorkSafe WA | Model WHS framework applies with local variations |
| TAS | WorkSafe Tasmania | Model WHS framework applies |
| ACT | WorkSafe ACT | Model WHS framework applies |
| NT | NT WorkSafe | Model WHS framework applies |
Related guides
- Construction SWMS - What Every Builder and Contractor Needs
- Concreting SWMS - What Work Requires One and What to Include
- Plumber SWMS - Which Jobs Require a SWMS and What to Include
Frequently asked questions
Does trenching require a SWMS?
Yes when the trench work is High Risk Construction Work, especially where it exceeds 1.5 metres in depth.
Does shallow excavation ever need a SWMS?
Yes. Services, unstable ground, plant, or nearby structures can make it high risk.
What should an excavation SWMS focus on?
It should focus on stability, services, access, spoil, plant, and support systems.
What is the main legal issue with trench work?
Preventing collapse, engulfment, and service strike before workers enter the excavation.
SWMS templates for excavation and trenching
- Excavation and Trenching SWMS for general trenching and excavation activities.
- Deep Excavation Over 1.5m and Ground Stability SWMS for deeper excavation work with collapse risk.
- Excavation Work Over 1.5 SWMS for trench and excavation activities above the key HRCW depth threshold.
- Excavation Shoring, Benching and Shielding SWMS for supported trench systems and ground control methods.