Excavation Safe Work Method Statement (SWMS)

What Is a Excavation SWMS?

An Excavation Safe Work Method Statement (SWMS) is a written document that sets out the high-risk work activities involved in a construction job. It outlines the risks associated with those activities and the control measures that will be put in place to manage them.

In Australia, this is not just administrative paperwork. It is a legal requirement for specific types of excavation. Under the model Work Health and Safety (WHS) laws, a SWMS must be prepared before High Risk Construction Work begins. For excavation, this generally applies whenever you dig deeper than 1.5 metres.

The document acts as a communication tool. It ensures the Principal Contractor, the subcontractors, and the workers all understand how the job will be done safely. It is not enough to just say "we will be careful". The SWMS must detail the exact steps, the potential dangers, and the specific methods used to control those dangers. It bridges the gap between high-level safety policy and the physical reality of a construction site.

For business owners, the SWMS is evidence of compliance. If a SafeWork inspector visits your site, this is one of the first documents they will ask to see.

When to Use This Document

You must use an Excavation SWMS whenever the work fits the definition of High Risk Construction Work (HRCW). According to Regulation 291 of the WHS Regulations, this specifically includes excavation work carried out in or near:

• A shaft or tunnel
• An excavation deeper than 1.5 metres

There are other times when it is smart to use one, even if the law does not strictly demand it. If you are digging near underground services, working in unstable ground, or using mobile plant close to the edge of an excavation, a SWMS is vital for managing risk.

State and Territory Variations

While most of Australia uses model WHS laws, there are slight differences in how they are applied.

• New South Wales, Queensland, South Australia, Tasmania, ACT, and Northern Territory: These jurisdictions follow the model WHS Regulations. The 1.5-metre rule applies strictly here. If you dig deeper than this without a SWMS, you face on-the-spot fines.
• Victoria: Victoria operates under the Occupational Health and Safety Act 2004. While the terminology differs, the requirement is similar. Regulation 5.1.31 of the OHS Regulations 2017 requires a written Safe Work Method Statement for any excavation deeper than 1.5 metres.
• Western Australia: WA has recently harmonised its laws with the Work Health and Safety Act 2020. Under the WHS (General) Regulations 2022, the requirement for a SWMS for excavation deeper than 1.5m is now consistent with the eastern states.

You should also refer to specific standards like AS/NZS 2865:2009 (Excavations). This standard provides technical benchmarks for safety. Regulators use it to determine if you have taken "reasonably practicable" steps to keep workers safe.

Key Sections and Required Elements

A generic document will not pass scrutiny. To be legally compliant, your Excavation SWMS must include specific content mandated by Regulation 295.

High-Risk Construction Work Details

The document must clearly state that it covers High Risk Construction Work. There should be a statement or checkbox identifying the specific nature of the hazard. For excavation, this means explicitly noting "Excavation work deeper than 1.5 metres".

Hazards and Risks

You must identify the risks associated with the work. This needs to be specific to the site. General risks include ground collapse, falling objects, and contact with underground services. You must tailor this to the location. For example, if there are overhead powerlines, they must be listed here.

Control Measures

This is the most important part. You must describe the control measures to be implemented. These must follow the Hierarchy of Controls. You cannot simply rely on Personal Protective Equipment (PPE). You need higher-level controls such as shoring, benching, or battering the excavation walls.

The regulations require you to describe how these controls will be implemented. It is not enough to write "use shoring". You must write "Install hydraulic aluminium shoring panels designed by a competent person prior to workers entering the trench".

Implementation, Monitoring and Review

The SWMS must explain how the control measures will be monitored. Who checks the shoring? How often? What happens if it rains? The document needs a clause that triggers a review if workplace conditions change.

Signatures

A SWMS is not valid until it is signed. The Principal Contractor (or PCBU) must sign it. Crucially, the relevant workers must also sign it to confirm they have read and understood the contents.

How to Write a Excavation SWMS (Step by Step)

Creating a robust SWMS takes time. You cannot simply fill in the blanks five minutes before the excavator arrives. Follow these steps to ensure you meet your legal duties.

Step 1: Assess the Scope and Site Conditions

Before you write, look at the site. What are the ground conditions? Is it rocky, clay, or sandy fill? What is below the ground? You must obtain "Dial Before You Dig" plans. These plans are essential for identifying underground cables and pipes.

Look at the surroundings. Is the excavation near a roadway? Are there buildings nearby that might be affected by vibration? This initial assessment forms the basis of your document.

Step 2: Select a Relevant Template

Start with a master Excavation SWMS Template. This saves time but be careful. The template must be relevant to the machinery you are using. Do not use a template for "manual trenching" if you are using a 20-tonne excavator.

Step 3: Consult with Your Workers

Regulation 295 and the Code of Practice both stress the need for consultation. You must talk to the people doing the work. They often know the practical risks better than the manager does. Hold a toolbox talk. Ask them what they think might go wrong. Include their input in the hazard identification section. This turns the SWMS from a form into a practical safety plan.

Step 4: Identify the Hazards

List the specific hazards. For a standard excavation job, this list usually includes:

• Ground collapse (trench failure)
• Underground services (gas, electricity, water)
• Falls into the excavation
• Falling objects (soil or rocks landing on workers)
• Mobile plant collision (excavator striking workers or other vehicles)
• Noise and vibration
• Hazardous atmospheres (lack of oxygen or toxic fumes)

Step 5: Assess the Risk Level

Use a risk matrix to rate the severity and likelihood of each hazard. This helps you prioritize where to focus your efforts. Ground collapse is usually rated as "Catastrophic" because it can be fatal. This requires the highest level of control.

Step 6: Select and Document Control Measures

Apply the Hierarchy of Controls.

1. Elimination: Can you avoid digging altogether? (e.g., using trenchless technology).
2. Substitution: Can you use a safer method?
3. Engineering: This is where most excavation controls sit. Use trench shields, boxes, or battering the banks to a safe angle.
4. Administrative: This includes your Site Induction Checklist, safety signs, and barricades around the hole.
5. PPE: High-vis clothing, hard hats, and steel-capped boots.

Write these measures clearly. For example: "Batter excavation walls to a 1:1 slope for depths up to 3 metres in stable soil."

Step 7: Describe Safe Work Methods

Break the job down into steps.

• Step 1: Set up exclusion zone.
• Step 2: Locate and pothole services.
• Step 3: Excavate to depth.
• Step 4: Install shoring (if required).
• Step 5: Perform work in trench.
• Step 6: Backfill and remove shoring.

Next to each step, write the safety actions required.

Step 8: Finalise and Sign

Ensure the date, site address, and company details are correct. The person in charge of the business must sign. Have a final meeting with the crew. Read the SWMS out loud. Give them a chance to ask questions. Once they understand it, they must sign.

Common Mistakes to Avoid

Inspectors issue infringement notices every day for poorly drafted SWMS. Avoid these common traps to keep your site safe and compliant.

Using "Cut and Paste" Documents

Buying a template is fine, but leaving the previous client's name in the footer is not. A SWMS must be site-specific. If your document describes "excavating near the Brisbane River" but you are working in a suburban street in Perth, it is invalid. Regulators will penalise you for generic, "cookie-cutter" documents that do not reflect the actual risks.

Ignoring Underground Services

One of the biggest risks in excavation is hitting a live gas or electrical cable. Failing to check "Dial Before You Dig" plans is a serious breach. Even worse, having the plans but not including a step to physically "pothole" (expose by hand digging) the services before using heavy machinery is a common failure.

Forgetting about Traffic Management

If the excavation affects the public road or footpath, you need a traffic management plan. The SWMS should reference this plan. If you have an excavator swinging over a public footpath without proper barriers and traffic control, you are exposing the public to risk.

Not Reviewing the SWMS

A SWMS is a living document. If the weather turns to rain and the trench starts filling with water, or if the soil type is different to what was expected (e.g., hitting rock instead of clay), you must stop and review the SWMS. Continuing work under changed conditions without updating the document is a breach of the Act.

Signing Blank Documents

Never ask workers to sign a blank SWMS to "sort out later". This defeats the purpose of the document. It also suggests that safety is an afterthought. If an incident occurs, a blank signature is evidence that you failed to consult or inform your workers.

Legal Considerations (AU)

Primary Duty of Care

Under Section 19 of the WHS Act, the Person Conducting a Business or Undertaking (PCBU) has a primary duty of care. This means you must do everything that is reasonably practicable to ensure the health and safety of workers. The SWMS is your main tool for demonstrating this duty.

Due Diligence

Company directors and officers are not immune. Under Section 27 of the Corporations Act 2001, officers must exercise due diligence to ensure the PCBU complies with its obligations. If a worker is injured and there was no SWMS, or a poor one, directors can be held personally liable. They cannot simply blame the site manager. They must actively ask to see the SWMS and verify it is adequate.

Strict Liability Offences

Failing to have a SWMS for high-risk excavation is often a strict liability offence. This means the prosecution does not need to prove you intended to break the law. They only need to prove the work happened and the document was missing. Penalties can be significant, ranging from on-the-spot fines for individuals to hundreds of thousands of dollars for corporations.

Access to Documents

Under the WHS Regulations, the SWMS must be accessible to all workers. If you keep the only copy in the site office 50 metres away from the trench, you may be breaching the law. Workers need to be able to refer to it, or at least have had it adequately explained to them, right where the work is happening. Digital SWMS platforms are becoming popular for this reason, as they allow the document to be accessed on a tablet or phone at the trench edge.

Frequently Asked Questions

How deep can I dig without a SWMS?

Under the model WHS Regulations, you generally need a SWMS for excavation deeper than 1.5 metres. However, if you are digging near a shaft or tunnel, or in ground that is unstable, the requirement may apply even at shallower depths. It is always safer to prepare a SWMS if you are unsure.

Can I use the same SWMS for every job?

No. You can use a master template, but you must adjust it for every site. The hazards, control measures, and site conditions must be specific to the location. Using a generic document for every site is a common reason for fines from SafeWork inspectors.

Do I need a SWMS for a post hole digger?

Generally, no. Post hole diggers used for fencing usually do not exceed the 1.5-metre depth. However, if the holes are deeper than 1.5 metres or if they are classified as a shaft or trench, you will need one.

Who is responsible for the SWMS?

The PCBU (usually the contractor or business owner) is responsible for preparing the SWMS. If multiple businesses are working on the site, the Principal Contractor must ensure the SWMS is in place. However, every employer must ensure their workers are aware of the risks and controls.

What is the difference between a JSA and a SWMS?

A Job Safety Analysis (JSA) is a risk assessment tool. A SWMS is a specific legal document required for High Risk Construction Work. A JSA can be used to help develop the content of a SWMS, but for high-risk jobs like deep excavation, the SWMS is the mandatory document.

Is a printed copy required?

It must be accessible. A digital copy on a phone or tablet is acceptable as long as the worker can read it and understand it. If reception is poor or the device runs out of battery, a physical backup is a good idea.