How a pipe wears through

Copper became the standard supply pipe in much of the housing built in Fullerton and nearby cities after the war. It lasts a long time, but not forever. Over decades the inside wall can thin from corrosion, high water velocity, and wear at elbows and fittings, until a hole the size of a pinpoint opens up.

Galvanized steel, found in some of the oldest homes, fails differently: it rusts from the inside, narrowing the pipe and lowering pressure, then eventually leaks at threads and weak spots. Either way, the result is a slow leak that can run for weeks before it shows.

Terms to know

Pinhole leak
A very small hole through the pipe wall, often spraying a fine stream.
Type M and Type L
Common copper pipe wall thicknesses; Type M is thinner than Type L.
Galvanized pipe
Steel pipe coated with zinc, used for supply lines in older homes.
Scale
Mineral deposits from hard water that build up inside pipes and fixtures.
Erosion corrosion
Wear caused by fast-moving water, often at elbows and tees.

Factors that can contribute

  • Age of the original pipe, especially in homes from the 1950s through the 1970s.
  • Hard water from a blend of local groundwater and imported supply.
  • High water pressure or water hammer.
  • Hot water lines, which see more expansion and wear.
  • Pipe in contact with concrete, soil or dissimilar metals.
  • Thin-wall pipe used in some original installations.

When one pinhole hints at more

  • IfIt is the first leak in decades and the cut-out pipe looks cleanA spot repair and monitoring may be enough.
  • IfThe removed pipe shows green or blue pitting insideAsk how widespread that corrosion is likely to be.
  • IfYou have had two or more pinholes within a few yearsConsider rerouting the affected lines or a repipe evaluation.
  • IfPressure is low throughout an older home with galvanized linesReplacement is often discussed, since the pipe is narrowing inside.

Can you prevent pinholes?

You cannot reverse age, but you can reduce stress on the system. Ask a plumber to check your water pressure; if it is high, a pressure regulator may be recommended. Address water hammer, the banging sound when valves close, and keep an eye on the meter and bill so a new leak is caught early. Whether a water softener or treatment system is worthwhile is a separate question worth discussing with a professional.

Common questions

Does a pinhole leak mean my whole house needs repiping?

Not by itself. One leak in otherwise sound pipe is often repaired. A pattern of leaks or visible internal corrosion is what usually leads to repipe discussions.

Can pinhole leaks happen in newer homes?

They can, but they are more common in older copper systems that have been in service for decades.

What pipe is used to replace old copper?

Plumbers commonly use new copper or approved plastic piping such as PEX. Ask why they recommend one over the other for your home.

General information for Fullerton, not a quote or professional advice. In an emergency, call 911.