Everything you need to know about plumbing

Long before anyone called it a trade, people were already working out the first golden rule. In the mid-third millennium BC, the Indus Valley city of Mohenjo-daro ran its household drains into covered brick sewers beneath the streets.

On Bronze Age Crete, the Minoan palace at Knossos carried water through tapered terracotta pipes, shaped so each section locked tightly into the next, while stone channels drained its courts.

Rome took it to scale. Aqueducts brought water into the city, and lead pipes, the fistulae, carried it on to fountains, baths and private houses. The craftsmen who made them were the plumbarii, from plumbum, the Latin word for lead.

The word stuck. A plumber was first a worker in lead, and lead still carries the chemical symbol Pb, for plumbum. That is where The Plumb Bumb gets its name and where the gold Pb comes from: a small nod to the trade’s oldest roots.

The metal itself has long since retired. Canada’s National Plumbing Code stopped accepting lead for water service pipes in 1975, and banned lead solder in new drinking-water plumbing by 1990. Older homes can still turn up a lead line, and a plumber can tell you if yours has one.