Quick answer
A pinhole leak is a tiny hole that corrosion has eaten through a copper pipe from the inside, often linked to water chemistry, high water velocity, or age. Shut off the water to that line, and a repair clamp can stop the drip temporarily. A lasting repair replaces the damaged section. One pinhole often means others are forming nearby, so if the house has had two or more, a plumber may recommend a repipe; HomeAdvisor puts a whole-house repipe at about $4.50 per square foot of house. Call (888) 217-6781 to reach a plumbing company taking calls in your ZIP.
Follow the short menu, then your 5-digit ZIP. The line goes quiet for a few seconds while it connects; stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed November 4, 2026· Next review May 2027
A pinhole leak is a hole smaller than a pencil point that corrosion has eaten through the wall of a copper pipe, from the inside out. It starts as a fine spray or a drip, often inside a wall or ceiling, and it is frequently found as a stain before anyone sees water.
Stop It Now
- 1Shut off the water at the fixture valve if there is one, or at the main. See emergency water shut-off.
- 2Dry the pipe and find the exact hole.
- 3Fit a pipe repair clamp, a rubber pad and a metal sleeve bolted over the hole. It is a temporary fix.
- 4Protect what is below. Put a pan under it, and if water has reached a ceiling or wall, see pipe burst in wall.
Why It Happens
The Copper Development Association's handbook describes how water chemistry and installation affect copper tube corrosion. In practice, pinholes are linked to:
- Water chemistry: pH, dissolved minerals and disinfectant levels.
- High velocity: undersized pipe or high pressure wearing the inside, especially in hot water recirculation lines.
- Sediment and grit scouring the pipe.
- Age: thin-wall copper installed decades ago.
- Installation: excess flux or burrs left inside joints.
Talk to a plumber about this
One call reaches a plumbing company taking calls in your ZIP.
Repair or Repipe
| Situation | Usual answer |
|---|---|
| First pinhole, pipe otherwise sound | Replace the damaged section |
| Second or third pinhole in a year | Ask about a repipe |
| Leaks in hot lines only, with recirculation | Check velocity and the pump |
| Green or blue stains at many fittings | Repipe likely |
A section repair cuts out a foot or two and replaces it with copper or PEX. A repipe replaces the supply lines; HomeAdvisor puts it at about $4.50 per square foot of house. See repipe house cost.
Also Check
Ask the water utility about the water's pH and treatment. If many homes in your area have pinholes, it is a known local issue.
The Call
Call to replace the damaged section, or right away if a pinhole is leaking inside a wall or ceiling. (888) 217-6781 connects you to a plumbing company taking calls in your ZIP. Follow the short menu, enter your 5-digit ZIP and stay on while it connects; if it does not connect, call once more, because the companies taking calls change minute to minute.
Reading to confirm what you already suspect?
Confirm it in two minutes instead — the pro on this line answers questions about YOUR situation all day: what it is, what it should cost, whether you even need service. If you want, they'll set the appointment on the same call.
No obligation to book
Frequently Asked Questions
What causes pinhole leaks in copper pipes?
Corrosion from the inside, linked to water chemistry such as pH and dissolved minerals, high water velocity, sediment, and age. Leaks often cluster in hot water lines and near fittings.
Can I fix a pinhole leak myself?
A pipe repair clamp stops the drip for now. A lasting repair cuts out the section and replaces it.
If I have one pinhole leak, will I have more?
Often. The conditions that made one hole are usually acting on the whole line. Two or more pinhole leaks are a common reason to repipe.
How much does it cost to repipe after pinhole leaks?
HomeAdvisor puts a whole-house repipe at about $4.50 per square foot of house, with labor about 70% of the total.
Sources
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
Equipment
Reviewed gear for this job
Those pages carry affiliate links. As an Amazon Associate, HearthDry earns from qualifying purchases; it costs you nothing extra.
Our Amazon storefront →