London Plumber Insurance: What to Check Before Booking Any Tradesperson

Why Plumber Insurance Matters

When a plumber or heating engineer works in your London property, they are carrying out work that can cause significant damage if done incorrectly or if an accident occurs. A pipe connection that fails after the engineer has left, flooding a kitchen or bathroom; a gas connection that develops a leak; a boiler installation that causes a carbon monoxide incident — all of these are scenarios where the engineer responsible should have insurance in place to cover the cost of remediation. An uninsured tradesperson working in your property leaves you exposed to bearing that cost yourself if no insurance is in place to cover it.

Public Liability Insurance

Public liability (PL) insurance covers third-party claims for bodily injury or property damage caused by the tradesperson during their work. If the engineer accidentally floods your kitchen while replacing a tap, or drops a tool through your bathroom floor, PL insurance covers the repair costs up to the policy limit. Most reputable London plumbers and heating engineers carry between £1 million and £5 million of public liability cover. For domestic residential work, a £1 million limit is usually sufficient. For work in commercial premises or on larger-value properties, £2 million or £5 million is more appropriate.

Always ask for the public liability insurance certificate before work begins — specifically, ask for the certificate of insurance showing the insurer name, policy number, the level of cover, and the expiry date. A reputable tradesperson will provide this without hesitation. If they cannot or will not provide evidence of PL insurance, do not allow them to start work on your property.

What Public Liability Insurance Does NOT Cover

Public liability insurance does not cover poor workmanship in itself — if the engineer fits a valve incorrectly and it fails a week later, PL insurance covers the resulting water damage to your property, but it does not guarantee that the valve will be refitted correctly or that a new valve will be supplied without additional charge. That is a contractual matter between you and the tradesperson. PL also does not cover damage to the item being worked on — it covers damage to other property. If the engineer damages your boiler while servicing it, PL insurance may not cover the cost of the damaged part; that depends on the specific policy wording and whether negligence can be established.

Employers Liability Insurance

If a plumbing company employs other people — apprentices, labourer assistants, or additional engineers — they are legally required to carry employers liability insurance under the Employers Liability (Compulsory Insurance) Act 1969. The minimum required level is £5 million. If a sole trader works entirely alone and does not employ anyone, employers liability is not required. When booking a company that sends multiple staff to site, ask whether employers liability is in place and request the certificate number.

Gas Safe Registration and Insurance

For gas work specifically, Gas Safe registration is the primary check — it confirms that the engineer is legally authorised to carry out gas work. Separately, most Gas Safe registered engineers also carry professional indemnity insurance in addition to public liability, which covers claims arising from negligent professional advice or design. For a straightforward boiler repair or gas safety certificate, PL insurance is the primary policy to check. For more complex work — boiler installation, gas pipework design, commercial gas installations — professional indemnity cover is also worth confirming. Checkatrade and MyBuilder, the two largest verified trade platforms operating in London, require their members to maintain public liability insurance and will suspend a member who lets their cover lapse.