Ask a tradie about professional indemnity insurance and you’ll usually get one of two reactions: “isn’t that for doctors and architects?” or “my broker said I need it but I don’t really know why.”
PI is the most misunderstood insurance in the trades. But in 2026, it’s also the one changing fastest. NSW is making it mandatory for registered building and design practitioners from July. More trades are doing design work than ever before — sparkies specifying switchboard configurations, plumbers designing hydronic systems, chippies doing structural design-build. If you provide advice, designs, specifications, or compliance certifications, you have PI exposure whether you realise it or not.
This guide explains what PI actually covers for tradies, who needs it, and what it costs.
What is professional indemnity insurance?
Professional indemnity covers you if your professional advice, design, specification, or certification turns out to be wrong and causes a financial loss to your client.
The key word is “financial loss” — not physical damage. If your faulty wiring burns down a house, that’s a public liability claim (physical damage). But if the electrical layout you designed turns out to be undersized for the client’s needs and they have to pay $30,000 to redo it, that’s a PI claim (pure financial loss from bad professional advice). PL won’t cover it. PI will.
PI covers:
- Design errors — the beam you spec’d is undersized, the drainage plan has a fall going the wrong way, the switchboard layout doesn’t meet AS/NZS 3000 requirements
- Specification errors — you specified materials that aren’t fit for purpose, fixtures that don’t meet the required standard, a system configuration that doesn’t work
- Advice errors — you told a client something was compliant when it wasn’t, you advised a certain approach that turned out to be wrong and costly
- Certification errors — you signed off on compliance that wasn’t achieved, you issued a certificate that turned out to be incorrect
- Omissions — you forgot to include something in your design or specification that should have been there, and the client suffered a loss because of it
- Defence costs — legal fees for defending a PI claim, even if the claim turns out to be baseless
Which tradies need PI?
The short answer: any tradie who provides professional advice or design beyond basic installation work. Here’s how it breaks down by trade:
Electricians — if you design electrical layouts, specify switchboard configurations, or do compliance certification beyond simple installation sign-offs, you have PI exposure. An undersized switchboard that costs $20,000 to replace because it can’t handle the load you specified is a PI claim. The NSW PI mandate from July 2026 may capture electricians doing design work under the Design and Building Practitioners Act.
Plumbers — if you design hydronic heating systems, specify commercial hot water systems, or do drainage design, you have PI exposure. A commercial kitchen drainage system that backs up because it was underspecified costs the restaurant owner lost revenue — that’s a PI claim, not a PL claim.
Builders — design-build is increasingly common. If you design the home extension you’re building, or you specify structural elements, you’re providing professional services. Even rough design work — sketches rather than formal engineering drawings — can create PI exposure. The NSW PI mandate from July 2026 explicitly captures registered building practitioners who do design work.
Carpenters — if you’re doing structural carpentry and making decisions about timber sizes, span tables, and connection details without an engineer’s sign-off, you’re essentially doing engineering. If it fails, your PL might cover the physical damage, but the cost of re-engineering and rebuilding correctly might not be covered without PI.
Project managers and construction supervisors — this is an obvious one. If you’re managing a build and your professional decisions cause the client financial loss, PI is essential.
Building inspectors and certifiers — obvious and usually mandatory. If you certify compliance that doesn’t exist, the financial consequences for the building owner are substantial.
Tilers and waterproofers — less obvious, but if you specify a waterproofing system that fails, the cost of stripping out a bathroom to re-waterproof is a financial loss on top of the physical damage. Some of this might be covered by PL (resultant damage) but the rectification cost beyond the physical damage might not be.
The test is simple: do you use your professional judgment to tell a client what should be done, rather than just doing what they ask? If yes, you have PI exposure.
NSW July 2026: the mandatory PI shift
The Design and Building Practitioners Act 2020 (NSW) is the single biggest regulatory change affecting tradie PI in decades. From 1 July 2026, registered design practitioners and building practitioners in NSW must hold PI insurance.
Who’s captured:
- Design practitioners — anyone who prepares regulated designs (architectural, structural, electrical, fire safety, mechanical, hydraulic) for class 2 buildings (apartments) and eventually other building classes
- Building practitioners — builders and trades who do building work on class 2 buildings and make compliance declarations
The act introduces a statutory duty of care — a legal obligation on anyone doing construction work to exercise reasonable care to avoid economic loss caused by defects. This is broader than traditional negligence law and creates PI exposure even for tradies who wouldn’t historically have needed it.
If you’re an electrician, plumber, or builder doing design work on multi-unit residential in NSW, assume you’re in scope. The exact boundaries are still being clarified, but the direction is clear: PI is moving from optional to mandatory for design-capable tradies in NSW, and other states are watching.
What PI costs for tradies
PI premiums are driven by your occupation classification, your turnover, the type of work you do, and your limit of indemnity. For tradies, typical limits are $1M or $2M.
Based on 2026 market quotes:
Electrician (with design work):
- $1M cover: $600-$1,500/yr
- $2M cover: $900-$2,500/yr
Builder (small residential, design-build):
- $1M cover: $1,000-$2,500/yr
- $2M cover: $1,500-$3,500/yr
Plumber (with design/specification work):
- $1M cover: $500-$1,200/yr
- $2M cover: $800-$1,800/yr
Building inspector/certifier:
- $1M cover: $1,500-$3,000/yr
- $2M cover: $2,500-$5,000/yr
Project manager:
- $1M cover: $800-$2,000/yr
- $2M cover: $1,200-$3,000/yr
PI is typically more expensive than PL per dollar of cover because PI claims are often larger and more complex. A building defect affecting 50 apartments can generate a PI claim in the millions.
Claims-made vs occurrence: the catch with PI
Most PI policies in Australia are claims-made, not occurrence-based. This is a critical distinction.
A claims-made policy covers claims made during the policy period, regardless of when the work was done. If you did design work in 2023, held a PI policy in 2023, but the claim is made against you in 2026, your 2023 policy won’t respond — your 2026 policy will (if you have one). If you don’t have a current PI policy when the claim is made, you’re uninsured for it, even though you were insured when you did the work.
This has two implications:
- You can’t buy PI once, let it lapse, and still be covered for past work. You need continuous PI cover.
- When you retire or leave the industry, you should consider run-off cover — a PI policy that covers claims made after you stop trading for work done while you were trading. Run-off cover is usually a one-time premium, often 2-3 times your annual premium, for a multi-year run-off period.
Do you need PI if you outsource all design?
If you never provide your own design or advice — you always engage an architect or engineer and strictly build to their specifications — your PI exposure is lower. But it’s not zero.
If you advise a client on which engineer to use, and that engineer turns out to be incompetent, you might have liability for negligent referral. If you alter a design on site without consulting the engineer — even for what seems like a minor practical adjustment — you might have stepped outside the engineer’s PI umbrella and into your own liability. If you make a compliance declaration based on someone else’s design that turns out to be wrong, you might share liability with the designer.
The safest approach: if you do any design, specification, or advice work, carry PI. If you genuinely do none of these things, document that clearly and make sure your contracts reflect it.
BizCover and PI
PI is a specialist product and not all online platforms offer it for tradies. BizCover does include PI for electricians and builders who need it as part of their trade insurance quote.
You can compare PI as part of a tradie insurance quote through BizCover — get a quote.
PI works alongside PL, not instead of it. For the full insurance picture, read our public liability guide and the state-by-state requirements — especially if you’re in NSW.
Frequently asked questions
What’s the difference between public liability and professional indemnity?
PL covers physical damage and bodily injury to third parties. PI covers financial loss from your professional advice, design, or certification. If your ladder scratches a car, that’s PL. If your design says the building can support a rooftop plant room and it can’t, and the client has to pay $100,000 to reinforce the structure, that’s PI.
Do I need PI if I’m a subcontractor working under a builder’s design?
Probably not for the design itself — the builder (or their designer) carries the design liability. But if you provide any advice, make any design decisions, or alter anything on site, you might create your own PI exposure. If the builder asks “can we do it this way instead?” and you say yes, you’ve just given professional advice.
Is PI tax deductible?
Yes. PI premiums are a deductible business expense in the year you pay them.
Can I get PI if I’ve had a claim against me before?
Yes, but it’ll cost more and you’ll need to disclose the claim history. Some insurers specialise in PI for trades with claims history; they charge higher premiums but provide cover that standard insurers might decline.
Does PI cover me for work I did before I bought the policy?
This is the retroactive date question. When you first buy PI, the policy will have a retroactive date — often the same date the policy starts. Work done before that date isn’t covered. Some policies offer retroactive cover back to when you first started trading, but this is an extension you need to request and it costs more. When you renew, the retroactive date should stay the same (the date of your first PI policy), maintaining continuous cover for all work done since.
The information in this guide is general in nature and does not take into account your individual circumstances. PI requirements vary by trade, state, and the specific nature of your work. The NSW Design and Building Practitioners Act 2020 is subject to regulatory development and interpretation. Consult a licensed insurance broker for advice specific to your situation. Read the Product Disclosure Statement (PDS) before purchasing any insurance product.