How long does plumbing last

Copper supply pipe lasts 50 to 70 years. PEX lasts 40 to 50. Cast iron drain pipe lasts 50 to 100. Galvanised steel lasts 40 to 50 and most of what is still installed is past that.

Those numbers matter because plumbing is the system in a house that fails quietly for years and then all at once, and the material in your walls tells you roughly where you are.

What lasts how long

The two materials to replace regardless of age

Polybutylene. Grey plastic supply pipe with crimped bands, installed roughly 1978 to 1995. It fails at fittings and along its length, it was the subject of one of the largest class actions in American construction, and insurers increasingly refuse to cover houses that still have it. If you have it, you are budgeting a repipe.

Orangeburg. Bituminous fibre sewer pipe, essentially tar paper rolled into a tube, used from the 1940s to the 1970s. It does not crack, it deforms into an oval and then collapses. A camera inspection identifies it in seconds.

Lead supply lines, from before the 1986 federal ban, belong on this list for a different reason. Many utilities now fund replacement; ask before you pay.

What decides where in the range you land

Water chemistry. Aggressive water, low pH or high chlorides, eats copper from the inside. Two identical copper systems in different towns can differ by twenty years.

Water pressure. Anything above 80 psi stresses every joint continuously. A $15 gauge on an outside tap tells you, and a pressure reducing valve is $350 to $800. It is the cheapest life extension available to a plumbing system.

Water temperature. Hot lines fail before cold ones, consistently. A house with a water heater set to 140°F wears its hot side faster than one set to 120°F.

Hardness. Scale narrows pipe and shortens water heater life sharply. Above about 10 grains per gallon it is worth softening on equipment grounds alone.

Installation. Copper with a burr left inside a fitting erodes at that point for thirty years and then leaks there.

The signs the system rather than a fixture is failing

One leak is a leak. These say the system:

• Two or three failures in different places within two years
• Water that runs rusty first thing in the morning from every tap
• Pressure that has fallen gradually everywhere over years
• A plumber showing you green or white crust at multiple joints
• Visible pinholes on more than one run

At that point the question stops being what the repair costs and becomes what a repipe costs: $4,500 to $12,000 in PEX, $8,000 to $22,000 in copper.

The maintenance that actually extends it

Short list, all cheap, in order of value:

1. Check the pressure. $15 gauge, ten seconds, and above 80 psi fix it.
2. Replace rubber washing machine hoses with braided steel. Twenty dollars. Failed hoses are among the most common household floods there is.
3. Flush the water heater annually where water is hard. Sediment on the bottom insulates the burner from the water and cooks the tank.
4. Exercise the shut-off valves once a year. A valve that has not moved in twenty years will not move when you need it.
5. Fix running toilets immediately. On a well or a septic system they cost more than water.
6. Insulate pipes in crawl spaces, attics and garages before the first freeze.

Frequently asked questions

How do I tell what my pipes are made of?

Look under a sink or at the water heater. Copper is copper coloured and rigid. Galvanised steel is dull grey, threaded, and a magnet sticks to it. PEX is flexible plastic, usually red, blue or white. CPVC is rigid cream plastic. Polybutylene is grey plastic with metal or plastic crimp bands, and it is the one to identify with certainty.

Should I repipe preemptively?

Only if the material is polybutylene, or the house is being gutted anyway and the walls are open. Otherwise repipe on evidence: repeated failures, not age alone. Plenty of 70 year old copper is fine.

Does a whole-house filter extend pipe life?

A sediment filter helps in water carrying grit. It does nothing for pH or chlorides, which is what actually attacks copper. If corrosion is the concern, test the water before buying equipment.

Is PEX as good as copper?

It resists freezing better, costs far less to install, and has no corrosion problem. It is damaged by UV, by rodents in a few documented cases, and its long-term record is 30 years rather than 70 because that is how long it has existed. For a repipe today it is the default choice for good reasons.

My house is 60 years old with original copper and no problems.

Then you have good water and a careful original installer, which is exactly the population that reaches 70. Check the pressure, replace the washer hoses, and repipe on evidence rather than on a birthday.