WHS Act overview for residential builders

In plain English

The Work Health and Safety Act 2011 (model law) is the foundation statute for workplace safety in Australia. It defines who owes safety duties, what those duties require, and what happens when they are not met. For residential builders, the Act creates layered obligations: the PCBU running the job owes the primary duty of care; officers of that PCBU owe a personal due diligence duty; workers (including subcontractors) owe duties to themselves and each other.

All jurisdictions except Victoria have adopted the model Act. Victoria operates under the Occupational Health and Safety Act 2004 (Vic), which covers the same ground but uses different terminology and structure. Western Australia adopted its version of the model laws on 31 March 2022 (verified 2026-05-10). For day-to-day construction work the practical obligations are broadly similar, but VIC builders must check WorkSafe Victoria guidance rather than Safe Work Australia when looking up specifics.

What it requires

PCBU primary duty of care (s 19)

A person conducting a business or undertaking (PCBU) must ensure the health and safety of workers and others, so far as is reasonably practicable. “Reasonably practicable” is defined in s 18 and balances likelihood of harm, severity, worker knowledge, availability of controls, and cost (verified 2026-05-10).

Under s 7, “worker” is broad: it includes employees, contractors, subcontractors, employees of subcontractors, apprentices, trainees, and volunteers. Engaging a subcontractor does not remove your PCBU duty (Safe Work Australia, Fact Sheet: WHS Duties in a Contractual Chain, verified 2026-05-10).

The specific obligations in s 19(3) require the PCBU to provide and maintain:

A work environment without risks to health and safety
Safe plant and structures
Safe systems of work
Safe use, handling, and storage of plant, structures and substances
Adequate facilities for the welfare of workers
Information, training, instruction or supervision necessary to protect workers
Monitoring of workers’ health and conditions

Officer due diligence (s 27)

An officer of a PCBU (a director, company secretary, or partner who participates in managing the business) must exercise due diligence to ensure the PCBU complies with its WHS duties. This is a personal duty: it cannot be delegated and does not disappear behind the corporate structure.

Section 27(5) of the model Act lists six elements of due diligence that officers must take reasonable steps to satisfy (verified 2026-05-10):

Element	What it requires
1. Knowledge	Acquire and keep up-to-date knowledge of WHS matters relevant to the business
2. Understanding operations	Understand the nature of the operations and the hazards and risks associated with them
3. Resources and processes	Ensure the PCBU has appropriate resources and processes to eliminate or minimise WHS risks
4. Reporting	Ensure the PCBU has processes for receiving and considering WHS information and for responding promptly
5. Compliance processes	Ensure the PCBU has processes for complying with duties under WHS laws
6. Verification	Verify that the above resources and processes are being used and are effective

For a residential builder running a company, this means the director cannot leave WHS entirely to a site supervisor. The director must know what HRCW is being carried out, confirm SWMS documents are in place, and verify that controls are actually being applied on-site.

Worker duties (s 28)

Workers (including subcontractors working on your site) must while at work (verified 2026-05-10):

Take reasonable care of their own health and safety
Take reasonable care that their acts or omissions do not adversely affect the health and safety of others
Comply with reasonable instructions from the PCBU
Cooperate with any reasonable policy or procedure relating to health or safety

Workers cannot be prosecuted under the model Act for simply failing to comply with a safety instruction; that is dealt with as an industrial matter. Prosecutions of workers under s 28 are reserved for conduct that puts others at risk.

Consultation, cooperation and coordination (ss 46-49)

When two or more PCBUs share a duty (which on any residential site with subcontractors is the normal state of affairs), each PCBU must, so far as is reasonably practicable, consult, cooperate and coordinate activities with every other duty holder (s 46, verified 2026-05-10).

Duty	What it requires in practice
Consult (s 47)	PCBU must consult with workers who are directly affected by a health and safety matter. Workers must be given a genuine opportunity to contribute.
Cooperate (s 46)	PCBUs sharing a worksite must share relevant WHS information and implement agreed controls.
Coordinate (s 46)	PCBUs must plan the work sequence so one trade’s activities do not create uncontrolled hazards for another.

A toolbox talk before a new subcontractor mobilises, documented with date and attendees, satisfies most consultation obligations in the model Act. See WHS duties when engaging subcontractors for the full consultation checklist.

Notifiable incidents (ss 35-38)

A PCBU must notify the state WHS regulator immediately on becoming aware of a notifiable incident. Notifiable incidents are defined across three sections (verified 2026-05-10):

Death (s 35): Any death of a person arising from the conduct of the business or undertaking is notifiable.

Serious injury or illness (s 36): Includes:

Immediate in-patient hospitalisation
Amputation of any body part
Serious head injury (fractured skull, loss of consciousness, intracranial bleeding)
Serious eye injury
Serious burn
Separation of skin from underlying tissue (degloving, scalping)
Spinal injury
Loss of bodily function
Serious lacerations requiring suturing
Any bone fracture other than a finger or toe
Medical treatment required within 48 hours of exposure to a substance

Dangerous incident (s 37): An incident that exposes any person to a serious risk, even if no injury results. Includes:

Uncontrolled escape, spillage or leakage of a substance
Uncontrolled implosion, explosion or fire
Uncontrolled escape of gas or steam
Electric shock
Fall or release from a height of any plant, substance or thing
Collapse or partial collapse of a structure
Collapse or failure of an excavation or shoring

Duty to notify (s 38): Notify the regulator immediately by phone (or online). A written report must follow within 48 hours for a dangerous incident. The incident site must be preserved until an inspector attends or gives clearance, except to attend to injured persons, make the site safe, or prevent further incidents. Records of notifiable incidents must be kept for at least 5 years (Safe Work Australia, verified 2026-05-10).

On a residential construction site, the most common notifiable incidents are: a worker falling from height (if a serious injury results or the fall exposed others to serious risk), a structural collapse, trench collapse, or unexpected electrical contact.

Penalties (ss 31-33)

The model WHS Act creates three categories of offence indexed annually. As at 1 July 2025, model WHS Act maximum penalties are (Safe Work Australia, verified 2026-05-07):

Category	Conduct	Body corporate	Officer	Individual
Category 1 (s 31)	Reckless conduct exposing a person to risk of death or serious injury	$11,839,000	$2,368,000 or 5 yrs imprisonment	$1,183,000 or 5 yrs imprisonment
Category 2 (s 32)	Failure exposing a person to risk of death or serious injury	$2,373,000	$475,000	$237,000
Category 3 (s 33)	Failure to comply with a duty (no risk of death/serious injury required)	$795,000	$159,000	$79,000

Category 3 is the baseline: failing to have a SWMS in place before HRCW is a Category 3 offence at minimum. If the failure exposes workers to risk of death or serious injury (for example, a roof framing task with no SWMS and no fall protection), prosecutors will charge Category 2. Category 1 requires proof of recklessness or gross negligence.

What it doesn’t cover

Licensing: builder and trade licences are covered by state fair trading and licensing acts, not the WHS Act
Workers’ compensation insurance: a separate scheme in each state, not covered by the WHS Act
Building product compliance: NCC product certification is a building act matter
Environmental obligations: EPA requirements, site contamination, and stormwater are separate regimes
Civil liability: the WHS Act is criminal in nature; breach opens a separate civil negligence claim but does not determine it

Practical implications

For the residential builder running the job:

Every job, every day: confirm workers (including all subcontractors) have white cards, know the site hazards, and are complying with the controls in place. On projects over $250,000 you are the principal contractor with additional formal obligations including a written WHS Management Plan.

As a company director or sole trader PCBU, your s 27 officer duty is personal. A fall injury on a job where you can’t demonstrate you verified the SWMS and the fall protection is evidence of failing to exercise due diligence.

For subcontractors:

You are a PCBU for your own workers and a worker in the principal contractor’s undertaking. Both roles attach simultaneously. Prepare your own SWMS for any HRCW and hand it to the principal contractor before you start.

For VIC builders:

The Occupational Health and Safety Act 2004 (Vic) covers the same ground. The regulator is WorkSafe Victoria. Key practical differences: the employer-duty language differs slightly, the terminology for HRCW and dangerous incident uses “employer” not “PCBU” in older guidance, and OHS Regulation 2017 numbers differ from the model WHS Regulations. Confirm specifics at worksafe.vic.gov.au.

For WA builders:

Western Australia adopted the model WHS Act (Work Health and Safety Act 2020 (WA)) with effect from 31 March 2022 (verified 2026-05-10). For work commenced before that date, the old Occupational Safety and Health Act 1984 (WA) may still be relevant to historical obligations.

Source link

Work Health and Safety Act 2011 (model law), Federal Register of Legislation (verified 2026-05-10)
Safe Work Australia: Duties under WHS laws (verified 2026-05-10)

References

Work Health and Safety Act 2011 (model law) ss 5, 7, 17, 18, 19, 27, 28, 35-38, 46-49 (verified 2026-05-10)
Safe Work Australia: Duties of a PCBU (verified 2026-05-10)
Safe Work Australia: Incident notification requirements under the model WHS Act (verified 2026-05-10)
Safe Work Australia: Maximum monetary penalties under WHS laws (verified 2026-05-07)
Safe Work Australia: Officer duty interpretive guide (verified 2026-05-10)
Safe Work Australia: Model WHS laws - jurisdictions (verified 2026-05-10)
WorkSafe Victoria: Occupational Health and Safety Act and regulations (verified 2026-05-10)