When plumbing work needs a Gas Safe engineer instead
Plumbers can install and repair most water systems, but any work on a gas appliance or gas pipework — a boiler, a gas fire, a gas hob — is illegal for anyone who isn't on the Gas Safe Register, by law. If a job involves both plumbing and a gas connection (moving a boiler, for example), check whether your plumber is also Gas Safe registered before booking.
Shared water supplies in flats and conversions
In a converted property, check whether your flat has its own independent stopcock and supply, or shares one with other flats via a communal system. A shared supply can mean a repair affects your neighbours too, and sometimes needs freeholder involvement before work starts.
Background checks and identity verification
Before booking, it's worth checking a plumber's trading history and identity, not just their registration — a landline or verifiable business address and reviews referencing specific jobs are stronger signals than a mobile number and a van sign alone.
Low water pressure — common causes
Low pressure can come from a partially closed stopcock, a fault with the water company's supply, scale build-up in old pipework, or (for a shower specifically) the type of shower valve fitted. A plumber can usually diagnose which of these it is by checking pressure at more than one fixture, rather than assuming it's the mains supply.
Copper vs plastic pipework
Copper pipework is the traditional standard and suits exposed runs; plastic (PEX/push-fit) pipework is faster to install and commonly used for pipework buried in walls or floors where copper joints would be harder to check later. Most plumbers use a mix depending on the specific run, not one material throughout.
Protecting pipes in cold weather
Pipes in unheated spaces — lofts, garages, outbuildings — are the most common source of a winter burst pipe once temperatures drop below freezing for a sustained period. Lagging exposed pipework and keeping heating on a low constant setting during a cold snap, rather than off, are the two most effective preventive steps.
Plumbing work and home insurance
Escape of water is one of the most common home insurance claims in the UK, and insurers sometimes ask whether recent plumbing work was carried out by a registered professional when assessing a claim. Keep receipts and any commissioning paperwork for significant work, not just for the boiler.
Combi vs system vs conventional boilers
A combi boiler heats water on demand with no separate tank, suits smaller properties with one bathroom. A system boiler uses a hot water cylinder but no cold water tank, better for higher demand. A conventional (regular) boiler uses both a cylinder and a tank, common in older properties and useful where mains pressure is poor.