Short answer: A pinhole leak is a tiny hole in a copper pipe wall, usually caused by corrosion from the inside. Water chemistry, high flow, sand and grit, high pressure and poor installation can all play a part. One pinhole can be repaired, but several in a short time often mean the copper is thinning and a repipe is the longer-term fix.
Copper has a strong track record as water pipe. But it isn't immune to wear. A pinhole leak can start as a fine spray inside a wall or a slow drip under a slab. Because it's small, it can run a long time before anyone notices. If you've found one, SRQ Leak Pros can connect you with a local pro for repiping in Sarasota or a single repair.
What is a pinhole leak?
It's exactly what it sounds like: a hole about the size of a pinhead in the pipe wall. It usually forms where the copper has thinned from the inside. Pressure pushes water out in a fine spray or a steady drip.
What causes pinhole leaks in copper pipes?
| Cause | How it works |
|---|---|
| Water chemistry | Certain water conditions can wear copper from the inside |
| High velocity | Fast-moving water, especially in hot recirculation lines, can erode pipe walls |
| Sand and grit | Particles in the water scour the inside of the pipe |
| High pressure | Extra stress on already thin spots |
| Poor installation | Excess flux, burrs or rough cuts can start corrosion |
| Contact with other metals | Mixed metals can speed corrosion at joints |
Pinholes often show up in clusters. Once one appears, others in the same part of the system may follow.
Found a pinhole leak? Call to reach a local pro who can check the rest of your copper.
Call (941) 541-0938Warning signs of a pinhole leak
- Small water stains on ceilings or walls
- Bubbling or soft drywall
- Green or blue spots on exposed copper
- A hissing sound inside a wall
- Mold or mildew smell
- A water meter that moves with all water off
- A warm spot on the floor, if the leak is under a slab
The EPA's two-hour meter test can catch a hidden leak: read the meter, use no water for two hours, then read it again.
Repair or repipe?
| Situation | Usually best |
|---|---|
| One pinhole in an exposed pipe | Spot repair |
| One pinhole in a wall | Spot repair, plus check nearby pipe |
| Two or more pinholes in a year | Talk about a repipe |
| Pinhole leak under the slab | Reroute or repipe; see slab leak repair |
| Green, thin pipe in many places | Repipe |
Angi's national data puts the average slab leak repair at about $2,300. If you're paying for several of those, a repipe may cost less in the long run.
Common repair methods
- Repair coupling. The damaged section is cut out and a coupling or new section is soldered or pressed in.
- Clamp. A temporary clamp can slow a leak until a proper repair.
- Reroute. A new line bypasses the damaged section.
- Epoxy lining. Coats the inside of the pipe; suitable for some systems.
- Repipe. New PEX or copper throughout the home.
Pinhole leaks in Florida homes
Many Florida homes are built on concrete slabs, so pinhole leaks in copper under the floor become slab leaks. They're harder to find and fix than a leak in an exposed pipe. Read what a slab leak is for the signs.
How to lower the risk of pinhole leaks
- Check water pressure. Ask a pro to test it, and add a pressure reducing valve if it's high.
- Ask about water chemistry. A pro or water treatment specialist can explain whether your water is hard on copper.
- Watch hot recirculation lines. Constant flow can wear them faster.
- Catch leaks early. Read the meter monthly.
- Plan ahead. If your copper is old and leaking, plan a repipe before the next leak.
Can you stop pinhole leaks from coming back?
You can lower the risk, but you can't undo thinning that has already happened. Fixing high pressure, water chemistry or high flow helps the pipe you have last longer. If the copper has already leaked in several places, new pinholes are likely. At that point, a repipe with PEX or new copper is usually the only way to end the cycle. A pro can cut out a short sample of pipe to show how thin the walls are.
Is PEX better than copper for a repipe?
Both work well. Wikipedia notes PEX is used mainly in building pipework and domestic water piping, and it resists the scale and corrosion that affect metal pipe. Copper has a long track record and handles heat well. Ask the pro why they recommend one for your home.
Local note: older slab homes in Bradenton often have decades-old copper. Ground-floor condos on Longboat Key and Siesta Key may share risers and walls, so a pinhole can affect neighbors.
Related reading: if your home is from the late 1970s to the 1990s, check for polybutylene pipes too. For costs, see the slab leak repair cost guide. Compare repipe prices, and see problems with CPVC pipe and galvanized steel pipe replacement.
When should you call a plumbing professional?
Call a pro when:
- You see a stain, a spray or green spots on copper
- You've had more than one pinhole leak
- The meter moves with all water off
- You feel a warm spot on the floor
Pinhole leaks adding up? Call (941) 541-0938 to reach a local repipe pro.
Call (941) 541-0938Frequently asked questions
Can a pinhole leak fix itself?
No. Minerals may slow it briefly, but the pipe stays weak and the leak usually grows.
Are pinhole leaks an emergency?
Not usually, but they shouldn't wait. Turn off water to that area if you can, and arrange a repair soon.
Does homeowners insurance cover pinhole leaks?
Many policies cover sudden water damage but not the pipe repair. Long-term leaks may be excluded. Check your policy.
How many pinhole leaks before I should repipe?
There's no set number, but two or more in a short time is a common sign the copper is thinning. Ask a pro to assess the system.
Sources
Related guides
Pipes & RepairsPolybutylene Pipes in Florida Homes: Risks and Replacement
How to tell if you have polybutylene, why it fails, and what replacing it involves.
Finding LeaksWhat Is a Slab Leak? Causes, Signs and Fixes
A plain-English guide to leaks under concrete floors: what causes them and what to watch for.