Kitchen plumbing and appliance connection

Kitchen plumbing is sequencing as much as pipework. Supplies and wastes have to be in position before the units go in, because a 15mm tail that emerges in the middle of a cabinet where a drawer runner needs to be means taking the unit apart later. On a refit, the plumber wants the kitchen plan with the appliance positions marked before first fix, and half a day on site while the units are being installed for the connections.

Wastes are where kitchens go wrong. A sink, a dishwasher and a washing machine sharing one trap and a long horizontal run will siphon and smell. Each appliance wants its own spigot on the trap or a standpipe, the run needs a fall, and the washing machine hose has to loop up above the trap so the machine cannot siphon. Those are small details that decide whether the kitchen smells in two years.

Boiling water taps have become common and bring requirements of their own: an under-sink tank needing a socket, a filter that has to be reachable for changing, and enough cupboard space next to the waste. Instant hot taps also need the mains pressure to be within the manufacturer's range, which is worth checking before buying one.