What a pinhole leak is

A pinhole is a small hole, often no bigger than the tip of a pen, that forms where the copper wall has thinned from the inside. It can start as a slow seep and grow. Above ground you might see a fine spray or a green-blue crust on the pipe. Under a slab you see none of that, only the meter, the bill, or a warm floor.

Pinholes are a type of corrosion failure. That matters because corrosion rarely affects only one spot; if conditions caused one hole, they may have thinned other parts of the same line.

Anaheim's water at a glance

Supplier
Anaheim Public Utilities, the city's own water utility
Sources
A blend of local groundwater and imported water
Hardness
On the hard side; scale on fixtures is common
Where to learn more
The utility's published water quality report

What is known and what is not

Reasonably well understood

  • Pinholes are internal corrosion of the copper wall
  • They tend to recur on pipe affected by the same conditions
  • Hot water lines are frequently involved
  • Hard water leaves scale on fixtures and in heaters

Not settled

  • How much hardness alone contributes to pinholes
  • Which combination of chemistry, flow and pipe quality caused a given leak
  • Whether water treatment will prevent future pinholes in existing pipe
  • How long the remaining pipe will last

One pinhole: what it might mean

  • IfIt is the first leak in an older copper systemThenA spot repair can be reasonable; ask to see the removed pipe and note its condition.
  • IfThe removed pipe looks pitted or thin beyond the holeThenExpect more and discuss a reroute of that run.
  • IfPinholes have appeared on more than one lineThenAsk for a repipe evaluation and a second opinion.
  • IfYou also see pinholes in exposed copper in the garage or atticThenMention it; it suggests a house-wide pattern rather than a one-off.

What you can do

  • Look at exposed copper near the water heater and under sinks for green or white crusting
  • Keep the cut-out section of any repaired pipe
  • Keep a simple log of leak dates and locations
  • Ask a plumber to check your water pressure and regulator
  • Talk to a qualified professional before buying water treatment specifically to stop leaks

Common questions

Is Anaheim's water unsafe because it is hard?

Hardness is about minerals like calcium and magnesium and is mainly a scale and taste issue. For questions about water quality and safety, the city's water quality report and utility are the right sources.

Can a pinhole seal itself?

Occasionally mineral deposits slow a tiny seep, but that is not a repair. Treat any confirmed leak as needing a fix.

Do pinholes mean my copper was defective?

Not necessarily. Installation, water conditions and the environment around the pipe all play a part, and the cause is often uncertain.

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