First fix and second fix plumbing
On a new build or extension, "first fix" is running pipework through walls and floors before they're closed up; "second fix" is fitting the visible taps, radiators and appliances once decorating is done. Timing this with other trades on site matters — pipework needs to be pressure-tested before it's covered over, not after.
Plumbing in older and period properties
Older properties sometimes still have lead or galvanised steel pipework, which can affect both water quality and pressure, and original layouts weren't designed around modern demand for multiple bathrooms. A plumber working on a period property will often check what the existing pipework is made of before quoting for anything beyond a like-for-like repair.
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.
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.
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.
Red flags in a cheap plumbing quote
A quote significantly below the others is worth questioning before accepting — check it specifies the same quality of parts (a boiler make/model, not just "a boiler"), includes making good after any pipework is exposed, and covers testing before the job is signed off as complete.
Three steps to hiring the right plumber
First, check they're registered with a WaterSafe scheme (or Gas Safe too, if the job needs it) and ask for the registration number. Second, get a written quote that separates labour from parts. Third, ask what happens if the job uncovers a bigger problem — a good plumber will tell you before continuing, not after.
Connecting new kitchen appliances
A new dishwasher or washing machine needs its own isolation valve and a suitable waste connection — if you're changing from an old appliance in a different position, this sometimes means new pipework rather than just reconnecting to the old point.