Pinhole leaks in copper water lines

At a glance

Where they appear

Hot water lines, near fittings, horizontal runs

Contributing factors

Water chemistry, high velocity, poor original solder work

Spot repair

Cut out and replace a short section

Bigger fix

Section or whole-house repipe

Why copper pits

Copper has served Etobicoke homes well for decades, but it can corrode from the inside in pits that eventually break through. Hot water lines suffer more, as do runs where water moves fast through undersized pipe or where flux was left inside joints during the original installation.

• A green or blue crust on the outside of the pipe near a joint is often the first visible clue.

Repairing the hole

We shut the water, drain the line, cut out the affected section and replace it with new type L copper or a PEX transition if that makes sense for the run. Repair clamps are a temporary measure for emergencies; we do not leave them in place as the permanent fix.

• The removed piece is worth a look.
• If the inside wall is pitted all around, other parts of the same run are probably thin too.

When to think about more

One pinhole in thirty years is bad luck. Three in a year is a pattern. At that point we talk about replacing the worst runs or the whole system so you stop chasing leaks from room to room.

• We will explain the options and leave the decision to you.

Signs to watch for

• Fine spray or hissing near a pipe
• Green crust on copper fittings
• Wet insulation in a basement ceiling
• Small rust spots on ductwork below a pipe
• Repeat leaks on the same run

How the job runs

1. Find the pinhole

   We dry the area and locate the exact spot.

2. Shut and drain

   The branch is isolated and drained.

3. Replace the section

   A new piece of pipe is fitted.

4. Inspect the run

   We examine the removed pipe and nearby joints.