How to Repair a Pinhole Leak in Copper Pipe
Updated February 25, 2026
Fix a pinhole leak in copper water pipe with a push-fit repair coupling, solder patch, or epoxy -- temporary and permanent repair options.
Overview
A pinhole leak in copper pipe is a tiny hole caused by internal corrosion (pitting corrosion) that eats through the pipe wall from the inside out. You see a small bead of water or a fine spray at one point on the pipe. Left alone, the hole gets bigger. The pipe behind it is likely corroding in other spots too. For an immediate fix, a push-fit repair coupling (SharkBite or similar) is the fastest permanent repair -- cut out the damaged section, push the coupling on, done. For a quick temporary fix while you plan the real repair, pipe repair tape or epoxy putty buys you days to weeks.
What You'll Need
Safety First
- Turn off the water supply before cutting into any pipe. Even a pinhole is pressurized -- cutting near it with a tube cutter or hacksaw sprays water.
- Drain the pipe section by opening faucets above and below the repair point. Water in the pipe prevents soldering and weakens epoxy bonds.
- If you see multiple pinhole leaks on the same pipe run, the entire run is corroding and needs replacement, not patching. Spot repairs on heavily corroded pipe are temporary.
Step-by-Step Instructions
- Assess the Damage
One pinhole on an otherwise clean pipe is a localized repair. Multiple pinholes, green corrosion patches, or soft spots mean the pipe section is failing systemically. For a single hole: repair it with a coupling or solder. For multiple holes in the same section: cut out the entire affected length and replace with new copper or PEX. For green corrosion across many pipe runs: plan a repipe -- patching buys time but the other sections will fail soon.
Tip: Green patina on the outside of copper pipe is normal surface oxidation and does not indicate a problem. Green crust with white mineral deposits concentrated at one spot means active corrosion from the inside -- that is where the next pinhole will appear. - Temporary Fix: Pipe Repair Tape or Epoxy
For a quick stop-gap while you get materials for a proper repair: dry the pipe surface around the hole thoroughly. Apply self-fusing silicone repair tape (Rescue Tape, $8-$12) stretched tightly around the pipe, overlapping each wrap by half. Or knead epoxy putty (JB Weld WaterWeld, $5-$8) and press it over the hole. Both work under pressure for days to weeks. Neither is a permanent repair -- plan the real fix within a week.
Tip: Pipe repair clamps ($3-$8) are another temporary option. A small stainless steel clamp with a rubber gasket wraps around the pipe and tightens over the hole. More reliable than tape and lasts longer, but still temporary. - Permanent Fix: Push-Fit Repair Coupling (No Solder)
Turn off the water. Drain the pipe. Cut out a 1-inch section of pipe centered on the pinhole using a tube cutter (not a hacksaw -- the cut must be perfectly round and burr-free). Deburr both cut ends with the deburring tool on the tube cutter or a round file. Mark the insertion depth on each pipe end (printed on the SharkBite fitting package). Push one end of the slip coupling onto one pipe, then slide it onto the other pipe until both marks are hidden. The coupling seals on both ends with O-rings and stainless steel teeth. Turn the water back on and check for leaks.
Tip: SharkBite slip couplings ($8-$15) are designed specifically for this repair. The slip design lets you push the coupling onto one pipe and then slide it over to capture the other -- no need to flex the pipes apart. Buy the correct size: 1/2-inch, 3/4-inch, or 1-inch to match your pipe diameter. - Permanent Fix: Solder Repair (Traditional)
For those who prefer soldering: cut out the damaged section. Cut a replacement piece of copper the same length. Clean all four pipe ends and the inside of two couplings with emery cloth until bright and shiny. Apply flux. Assemble the couplings over the pipe ends. Heat the coupling with a propane torch (not the solder, not the pipe). Touch the solder to the joint -- it should wick into the gap by capillary action. A properly soldered joint shows a thin, uniform ring of solder around the entire joint. Let it cool, wipe with a damp rag, turn on the water and check.
Tip: The pipe MUST be completely dry inside for solder to work. Even a slow drip prevents the joint from reaching soldering temperature. Stuff bread into the pipe upstream to absorb residual water -- it dissolves and flushes out when you turn the water back on.
Pro Tips
- Pinhole leaks in copper are caused by pitting corrosion from aggressive water chemistry: low pH (acidic water), high dissolved oxygen, high chlorine, or high velocity in undersized pipes. If you get pinhole leaks frequently, have your water tested. Treatment at the source prevents future failures.
- A single pinhole in a 20-year-old copper pipe is normal wear. Multiple pinholes in pipes under 10 years old indicates a water chemistry problem. Contact your water utility or have a corrosion specialist test your water.
- Push-fit couplings (SharkBite) are approved for permanent installation by all major plumbing codes and are accepted inside walls. Despite persistent myths, they are not temporary fittings -- they are rated for the life of the pipe system.
- If the pinhole is on a horizontal pipe near a joist or in a tight space where a tube cutter cannot rotate, use a mini tube cutter ($8-$12). It has a smaller swing radius and works in spaces where a full-size cutter will not fit.
- Insulate repaired sections with foam pipe insulation to reduce condensation. Condensation on cold copper pipes in humid basements accelerates external corrosion.
When to Call a Pro
Call a plumber if there are multiple pinhole leaks across different pipe runs (systemic corrosion -- the house may need a partial or full repipe), if the leak is inside a wall and you cannot access the pipe without opening the wall, if the pipe is in a slab foundation (requires jackhammering to access), or if you need a water chemistry analysis to determine why the pipes are corroding.
Frequently Asked Questions
When should I call a plumber to repair a pinhole leak in copper pipe?
Call a plumber if there are multiple pinhole leaks across different pipe runs (systemic corrosion -- the house may need a partial or full repipe), if the leak is inside a wall and you cannot access the pipe without opening the wall, if the pipe is in a slab foundation (requires jackhammering to access), or if you need a water chemistry analysis to determine why the pipes are corroding.
What are some expert tips to repair a pinhole leak in copper pipe?
Pinhole leaks in copper are caused by pitting corrosion from aggressive water chemistry: low pH (acidic water), high dissolved oxygen, high chlorine, or high velocity in undersized pipes. If you get pinhole leaks frequently, have your water tested. Treatment at the source prevents future failures. A single pinhole in a 20-year-old copper pipe is normal wear. Multiple pinholes in pipes under 10 years old indicates a water chemistry problem. Contact your water utility or have a corrosion specialist test your water. Push-fit couplings (SharkBite) are approved for permanent installation by all major plumbing codes and are accepted inside walls. Despite persistent myths, they are not temporary fittings -- they are rated for the life of the pipe system. If the pinhole is on a horizontal pipe near a joist or in a tight space where a tube cutter cannot rotate, use a mini tube cutter ($8-$12). It has a smaller swing radius and works in spaces where a full-size cutter will not fit. Insulate repaired sections with foam pipe insulation to reduce condensation. Condensation on cold copper pipes in humid basements accelerates external corrosion.
What tools do I need to repair a pinhole leak in copper pipe?
You will need: Tube cutter or mini tube cutter ($8-$20), SharkBite slip coupling ($8-$15, sized to match pipe diameter), Deburring tool (built into most tube cutters), Marker (to mark insertion depth), Bucket and towels (for catching residual water), For solder method: propane torch, lead-free solder, flux, emery cloth, copper couplings.
When should I call a professional instead of doing this myself?
Call a plumber if there are multiple pinhole leaks across different pipe runs (systemic corrosion -- the house may need a partial or full repipe), if the leak is inside a wall and you cannot access the pipe without opening the wall, if the pipe is in a slab foundation (requires jackhammering to access), or if you need a water chemistry analysis to determine why the pipes are corroding.
How difficult is this project?
This project is rated intermediate. It requires moderate DIY skill and the right tools.
How long does this take?
Plan for approximately 15 - 60 minutes depending on method. First-timers may need extra time.
How much will this cost?
The estimated cost is $5 - $25. Costs vary by location and materials chosen.