Workmanship guarantees on plumbing work
Most registered plumbers offer a workmanship guarantee separate from any manufacturer's warranty on parts like a boiler or a shower unit — commonly 12 months upwards. Ask what's specifically covered: a guarantee on a bathroom refit should cover the plumbing work itself, not just the visible fittings.
Understanding the labour vs materials split
Materials — pipework, fittings, a new boiler or bathroom suite — are often a smaller share of a plumbing quote than labour, particularly for jobs involving lifting floors or chasing walls. If a quote looks unusually cheap, check whether it specifies the same brand/quality of fittings as a competing quote, not just a lower labour rate.
Boiler pressure and heating faults
Most combi boilers run best between 1 and 1.5 bar of pressure — too low and the heating cuts out, too high and the pressure relief valve can discharge. A plumber checking a heating fault will usually look at pressure, check for trapped air in radiators (bleeding), and check the pump and diverter valve before assuming a full boiler fault.
Seasonal plumbing checks worth doing
Before winter: check outside tap isolation valves, and consider draining down any external pipework not in regular use. Before summer: check garden irrigation and outside tap connections for wear, since these see much more use once the weather turns. A five-minute check avoids most seasonal callouts.
How plumbing quotes work
Describe the job, including whether it's an emergency, a planned repair, or a full installation, and mention access — under a suspended floor is very different from behind fitted units. Plumbers use this for an initial estimate; the final price is usually confirmed once they've seen the fault or the space in person.
Blocked drains — causes and what a plumber checks
Slow-draining sinks are usually a local blockage (grease, hair, food waste) that a plumber can often clear with rodding or a drain snake. A blockage affecting multiple fixtures at once, or gurgling sounds from other drains, points to something further down the system — sometimes needing a drain camera survey rather than guesswork.
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.