Sole Trader vs Company Structure for Melbourne Plumbing Businesses

Most Plumbers Start as Sole Traders, and That's Usually Right, at First

Sole trader is the default starting structure for a good reason: it's free to set up, requires only an individual tax return, and has none of the ongoing compliance overhead of a company. For a Melbourne plumber starting out, building a client base, working solo or with one apprentice, the simplicity outweighs any tax advantage a company might offer. The question isn't whether sole trader is wrong to start with; it's recognising the point at which growth changes the calculation.

The Tax Rate Crossover

As a sole trader, business profit is taxed at your individual marginal rate, which climbs to 45% (plus Medicare levy) above the top threshold. A company pays a flat 25% tax rate for base rate entities (turnover under $50 million and no more than 80% passive income). Once consistent annual profit pushes your marginal rate meaningfully above 25%, there's a real tax deferral advantage to operating through a company, profit retained in the company is taxed at 25%, with further tax only payable when it's distributed to you personally as a dividend (with franking credits offsetting some of that).

This is a deferral, not an elimination, money eventually taken out personally is still taxed at your marginal rate, adjusted for franking credits already paid by the company. The benefit is strongest when profit is retained in the business to fund growth (a second van, hiring an apprentice, working capital) rather than fully drawn out each year.

Asset Protection: Real, But Not Absolute

A company is a distinct legal entity, so in most circumstances business debts sit with the company rather than the director personally, genuine asset protection compared to a sole trader, whose personal assets are directly exposed to business liabilities and lawsuits. But the protection has hard limits. Directors remain personally liable for unpaid PAYG withholding and superannuation guarantee amounts under director penalty notice provisions, regardless of the company structure. And most lenders and larger suppliers will require a personal guarantee from the director before extending credit to a small company anyway, which undermines the asset-protection benefit for that specific debt.

The PSI Trap for One-Person Plumbing Companies

Incorporating doesn't automatically deliver the tax benefits above if the Personal Services Income (PSI) rules apply. Under Part 2-42 of the ITAA 1997, if most of the company's income is essentially payment for one person's labour and skill, the PSI rules can limit the deductions available and attribute the income back to the individual regardless of the company wrapper. A plumbing business that invoices multiple clients for completed jobs, supplies its own tools, and bears commercial risk for defects generally passes the results test or unrelated clients test and isn't caught. A sole operator working under close direction for a single builder client, invoiced through a personal company, is at real risk of PSI attribution, meaning the company structure delivers compliance cost without the tax benefit.

VBA Licensing and Business Registration

Your individual plumbing licence, issued by the Victorian Building Authority, is tied to you personally and carries across regardless of business structure, incorporating doesn't require re-licensing as a tradesperson. Business-level registrations (if operating under a specific contracting registration) are tied to the legal entity, so switching from sole trader to company typically requires a fresh business registration reflecting the new entity, separate from your personal licence.

Ongoing Compliance Cost of a Company

A company brings real recurring costs: ASIC annual review fees, a separate company tax return, more detailed financial statements, and generally higher bookkeeping fees to manage director obligations, dividend administration and Division 7A loan compliance (the rules governing money taken out of a company other than as wages or properly declared dividends). These costs should be weighed honestly against the tax deferral and asset protection benefits, for a plumber with modest, fluctuating profit, the extra compliance cost can outweigh the benefit.