Pipe Repair

This Fix-It Guide on pipe repair tells how plumbing pipe works, what often goes wrong, how to identify a pipe problem, and what parts and tools you will need to fix it. It then gives simple step-by-step instructions for how to solder copper pipe, how to connect a compression fitting on copper pipe, how to connect a flare fitting on copper pipe, how to  cut rigid copper with a pipe cutter, how to join plastic pipe, how to replace a leaking threaded iron or steel pipe, and how to patch rigid copper pipe with plastic pipe. Refer to other plumbing repair guides for information on other aspects of your home’s plumbing.

How Does a Pipe Work?

 Pipe Repair

Plastic (PVC) pipe comes in a variety of types, sizes, and connections.

Household plumbing pipes are installed in walls and under floors during construction. They carry fresh water to kitchens, bathrooms, utility rooms, and so on. A separate system carries waste water from a sink or toilet to the main drain and out of the house to the sewer or septic system.

Pipe is available in cast-iron, brass, copper, galvanized steel, and plastic. Fittings are connections between pipes that allow pipes to turn or attach to a fixture such as a faucet or water heater.

How the fittings are installed on pipe depends on the material. For example, copper pipes are soldered together or joined with compression or flare fittings. Plastic pipes are joined with plastic screw-on fittings or PVC cement. In addition, transition fittings can be used to join plastic and metal pipes.

What Can Go Wrong with a Pipe?

Pipe doesn’t move, nor is it subject to wear. So the greatest cause of pipe problems is age (pipes become brittle or corrode, fittings fail) or damage from freezing.

Fix-It Tip

Plumbing in your home was installed to follow local plumbing codes at the time the house was constructed. Before doing more than repairing existing pipe, check with local building departments to find out whether permits and inspections are required.

How Can I Identify a Pipe Problem?

If water leaks from a pipe, you can trace it to its source, then fix it. However, tracing it may require that you climb around under the house, in an attic, or maybe even open up a wall.

Fix-It Tip

Before tearing into a wall to fix a pipe, call a plumber. Consider it a “second opinion.” An experienced plumber can guesstimate where the hidden problem is and can make a less conspicuous entry.

What Do I Need for Pipe Repair?

Parts for repairing pipe and fittings are available from a plumbing supply outlet, large hardware store, or plumbing department of a home center. Tools you’ll need include these:

  • Pipe repair kit (for emergencies)
  • Pipe tape
  • PVC primer
  • PVC cement
  • Pipe cutter or hack saw
  • Small wire brush
  • Emery cloth
  • Flaring tool and reamer
  • Paste flux
  • Solder
  • Propane torch

What Are the Steps to Pipe Repair?

Solder copper pipe:

  1. Clean the inside of the fitting with a small wire brush or with an emery cloth until it begins to shine.
  2. Clean the outside of the pipe in the same manner as the fitting. Avoid touching the cleaned surfaces.
  3. Brush a thin coat of paste flux inside the fitting and outside the end of the pipe.
  4. Insert the pipe end into the fitting. Then turn it to spread the flux. Wipe off excess flux.
  5. Use a propane torch (on soft flame) to heat the pipe joint evenly until the pipe is hot enough to melt the solder.
  6. Apply solder around the entire joint rim. Carefully wipe off excess solder.

Connect a compression fitting on copper pipe:

  1. Slide a nut and ring over the pipe.
  2. Insert the pipe onto the connection.
  3. Slide the compression ring and nut to the threads and tighten the nut with a wrench.

Connect a flare fitting on copper pipe:

  1. Slide flare nuts over the pipe end.
  2. Clamp one end of the pipe into the flaring tool and screw the ram into the pipe end to flare it.
  3. Insert the flared end on to the connection, then screw the flare nuts onto the connection. Use two wrenches to tighten the nuts.

Cut rigid copper with a pipe cutter:

  1. Slide the pipe cutter onto the copper pipe.
  2. Tighten the cutting wheel until it lightly scores the surface.
  3. Rotate the pipe cutter around the pipe once, then tighten the cutter slightly and repeat until the pipe is cut.
 Pipe Repair

Use PVC primer followed by PVC cement to join plastic pipe.

Join plastic pipe:

  1. Cut the plastic pipe with a pipe cutter or hacksaw, bracing it so it doesn’t bend or rotate.
  2. Remove burrs from the end of the pipe with a utility knife or emery cloth.
  3. Insert pipe into the fitting to make sure it fits correctly, called a dry fit.
  4. Use a pencil to draw a line across the joint.
  5. For PVC pipe, apply PVC primer to the pipe and fitting, following directions on the primer can.
  6. For all plastic pipe, liberally apply cement to the outside of the pipe end and to the inside of the fitting.
  7. Immediately install the fitting on the pipe, making sure that the pencil lines are aligned.
  8. Remove excess PVC cement and let it dry for the amount of time specified on the PVC cement label.

Replace a leaking threaded iron or steel pipe:

  1. Shut off water to pipe and drain it.
  2. Cut through the damaged pipe with a hacksaw.
  3. Unscrew the cut sections from the fittings.
  4. Replace the old pipe with two nipples joined by a center union.
  5. Apply pipe tape to the nipple threads.
  6. Screw one nipple into the fitting and tighten with a wrench.
  7. Slide the ring nut over the nipple, then screw the hubbed nut onto the nipple.
  8. Screw the threaded nut onto the second nipple, then screw the nipple into the second fitting.
  9. Tighten the nipple and nut.
  10. Apply pipe tape to the threaded nut.
  11. Slide the ring nut to the center of the union and screw it on.

Patch rigid copper pipe with plastic pipe:

  1. Shut off the water supply to the damaged pipe and open a faucet to drain the pipe.
  2. Cut out the damaged pipe section with a pipe cutter or hacksaw. Clean off the end of the copper pipe.
  3. Measure the gap between the pipe ends.
  4. Cut rigid plastic pipe of the same diameter as the copper pipe to fit the gap, allowing for transition fittings. Clean off the end of the plastic pipe.
  5. Sweat solder the copper section of the fitting to the end of the copper pipe.
  6. Screw the brass and plastic sections of the fittings to the copper sections.
  7. Dry-fit the plastic pipe patch to make sure it fits properly.
  8. If you are using PVC, apply primer (see above). For all plastic pipes, apply solvent to the inside of the fittings and outside of the pipe ends.
  9. Reinstall the plastic pipe patch.

Fix-It Tip

Need to connect pipes of two different materials, such as copper to plastic or plastic to steel? First visit a plumbing store and describe what you’re trying to do to a knowledgeable clerk. There are special fittings made for various applications.