A plumber who turns up, fixes it and leaves the kitchen as they found it

Taps come first, because they fail first. A dripping tap is usually a worn washer on an older compression tap or a tired ceramic cartridge on a quarter-turn or mixer tap. Both are quick to change if the isolation valves under the sink work; if they do not, they get replaced at the same time so the next job is quicker. Where a tap is beyond saving, or you simply want a new one, the new tap is fitted with fresh flexible connectors and the old one taken away.

Toilets come second. A cistern that keeps filling is a fill valve that has stopped shutting off or a flush valve seal that is letting water through into the pan. A toilet that rocks, a pan that leaks at the base or a flush that needs holding down all have known fixes. Full toilet replacements, including swapping an old low-level or high-level cistern for a modern close-coupled or back-to-wall unit, are a common half-day job.

Then the rest: stopcocks that will not turn, ball valves in cold water tanks that overflow through the pipe outside, banging pipework (water hammer, usually a loose pipe clip or a fast-closing valve), noisy fill valves, pipework runs for new appliances, and outside taps with a proper double check valve.

A slow drip wastes water, but that is the least of it. Left alone, a weeping tap connector under a kitchen sink rots the cupboard base. An overflow pipe that drips outside stains the render and, in winter, freezes into a sheet of ice on the path. A toilet fill valve passing constantly can add a startling amount to a metered water bill without a puddle anywhere. And a stopcock nobody has turned in twenty years will not turn on the day the washing machine hose bursts.

That last one is worth a visit on its own. Knowing where the stopcock is and that it works is the single most useful thing in a plumbing emergency. Part of a routine plumbing visit is checking it, freeing it if it is stiff, and fitting a lever isolation valve beside it if it is the old brass gate type that eventually snaps.

London housing makes plumbing its own discipline. Victorian and Edwardian terraces have pipework that has been added to by every owner since the 1950s, so a run can change from lead to copper to plastic in one cupboard. Converted flats share soil stacks and often share stopcocks, so isolating one bathroom can mean tracing a pipe through a neighbour's hallway. Mansion blocks and post-war estates have communal risers where the isolation valve is in a service cupboard on the landing.

Lead pipework still turns up on the incoming main in older properties. It can be left alone if it is sound, but where it needs work, the right answer is usually to replace the section in copper or MDPE and fit a new stopcock. Hard water is the other London constant. Scale blocks tap aerators, seizes shower valves and furs up ball valves, so a plumber working here carries the spares to deal with it and will tell you when a scale problem is really a hot water cylinder problem.

Every job is priced before it starts. For the standard repairs, the price covers the visit, the labour and the common parts carried on the van, so a tap cartridge or a fill valve is fitted there and then. Where a part has to be ordered, such as a specific mixer tap or a discontinued cistern, you get the price for the part and the return visit in writing and decide before anything is bought.

What you will not get is a quote that changes when the job is done. If the plumber finds something else once the panel is off, you are shown it, told what it would cost to deal with and asked. Nothing is added to the bill that was not agreed. The emergency plumber service works the same way, priced before the work starts, even at night.

A good share of London plumbing is for people who do not live in the property. For landlords and agents the routine is built around not needing to be there: the tenant is contacted directly to arrange access, the work is photographed before and after, and the invoice describes what was done in plain terms so it can be passed on or filed for the deposit scheme. Where a tenant reports a problem that turns out to be misuse rather than a fault, that is written down too.

Recurring work for the same properties builds up a record. When the same flat has had three ball valves in two years, that pattern says the incoming pressure needs a regulator, and that is the sort of thing a plumber who keeps notes will spot. The same engineers handle the annual landlord gas safety certificate, so a plumbing repair and a CP12 can be booked on one visit.