How long do water pipes last

Pipes are the longest-lived working components in the house, and the least watched: everything is inside walls, under floors, behind cabinets. The useful reframe is that a plumbing system is three populations on three clocks (supply pipes, drains, and fittings), and the fittings clock runs two to three times faster than the other two.

What each part lasts

Part	Typical lifespan	What usually ends it
Copper supply pipes	40–70 years	pinhole corrosion, joint failure, electrolytic corrosion
PEX / plastic supply pipes	40–50 years	fitting failure, UV damage at exposed runs
Galvanised steel supply pipes	30–50 years	internal corrosion, flow restriction, joint leakage
Taps and mixer valves	10–20 years	cartridge failure, aerator clogging, seal wear
Shut-off valves	15–30 years	seizure, seal wear, corrosion
PVC drain pipes (internal)	50–75 years	joint leakage, blockage, impact damage
Cast iron drain pipes	50–100 years	internal corrosion, joint failure, collapse
Sewer connection (external)	50–100 years	root ingress, ground settlement, collapse

The ranges come from the durability handbooks and trade field data behind the planning model. Read the table’s shape before its numbers: a dripping tap at year 12 and a weeping copper joint at year 55 are both “a plumbing problem,” but one is a replaceable fitting on a fast clock and the other is a system approaching the end of its slow one. Diagnosing which population is failing is most of the decision.

Supply fails wet, waste fails slow

Supply pipes are pressurised, so their failures make water: a pinhole weeps into a wall cavity, a joint lets go, and the consequential damage accumulates silently until a stain or a smell surfaces it. That asymmetry is why an aging supply system justifies planning in a way drains rarely do. Waste pipes fail politely by comparison: slow drainage, smells, a joint that seeps at low pressure. The exception is the external sewer connection, where root ingress and ground settlement work invisibly; a camera inspection is cheap next to excavating a collapse.

The valve you never touch is the one that fails

Shut-off valves last 15 to 30 years, and seizure is their signature ending: a valve that has not been turned in a decade freezes in place, discovered at the worst moment, mid-leak, when it is the one part that has to work. Once a year, turn the main shut-off closed and open again. It is the cheapest test in this guide, and it converts the valve from an unknown into a known on the exact day you need it.

When to start planning

Pieter’s house in Leiden was built in 1968 and still runs its original galvanised supply pipes, fifty-eight years against a 30-to-50 range. The shower pressure has faded for years, and the water runs brown after every holiday. That is the bore closing, not a mystery; no fitting swap fixes it. He plans the repipe for the autumn as scoped work, room by room with the floors that were coming up anyway, and briefs it with a written mandate; the Dutch plumber rate guide carries the current hourly ranges for pricing it honestly. The unplanned version of this repipe happens after a burst, with the floor open in December.

What this means before you call anyone

Name the population before naming the problem: fitting, supply, or waste. It decides whether you need a small replaceable part, a scoped repipe, or a camera survey, and it is the difference between a quote you can compare and one you can only accept. You can run repair-versus-replace for an aging supply system in the free repair-or-replace calculator. The plan in appkeep tracks the three populations as separate components with their own clocks, so the tap, the valve test, and the eventual repipe each show up as their own line instead of one emergency.