How to stop leaks at threaded plumbing joints

A leak at a plumbing connection is not only wasting water, it’s costing you money. Threaded fittings are used in the plumbing industry to connect pipes and fixtures and those fittings will leak if they haven’t been sealed correctly.  Unfortunately, there is a common mistake, made by homeowners when attempting to seal a leak, they use plumbers putty instead of thread tape or joint compound. Professional emergency plumbers will use a pipe joint compound or thread tape on fittings before connecting them to seal the joints and prevent leaks.

To do this –

  • Turn off the water.
  • Cut the pipe on either side of the leak at least an inch away from the fitting. This will allow you to unscrew the fitting at the pipes joint.
  • Now disconnect the leaking joint, you can use pliers or an adjustable wrench. Firmly hold one side of the fitting while turning the other side anticlockwise to loosen and then separate the two pieces.
  • Clean both the male and female fittings threads, use a wire brush to remove any old pipe corrosion, compound or debris. A standard wire brush is best for cleaning the male fitting, but for a female connection, you will need a wire bottlebrush.
  • Apply a good coat of pipe joint compound to the threads on the male fitting, you don’t need to apply the joint compound to the female side. If you are using thread tape instead of joint compound, wrap the male threads with several layers of tape.
  • Thread the male fitting into the female fitting and tighten it until snug, then apply an extra half turn using your pliers or wrench.
  • Install a coupling to reconnect the pipes. PVC pipes will need to have the ends cleaned with a PVC cleaner. Apply a generous amount of PVC glue to the pipes and connect with the coupling. If using copper pipes, you’ll need to clean the end of the pipe using sandpaper, apply the pipe flux and join the two pipes with a copper coupling and solder them together.
  • Turn on the water supply to check for leaks.

What you’ll need

  • Pliers or adjustable wrench
  • Wire brush
  • Rags
  • Pipe joint compound
  • Couplings
  • PVC cleaner
  • PVC Glue


  • Soak any hard to remove fittings with some penetrating oil
  • Pipe flux is a compound that helps to prevent oxidation during soldering
  • Apply thread tape to the male connection first, then a coat of pipe joint compound as an added measure to seal the fittings.
  • You must use CPVC (chlorinated polyvinyl chloride) glue to connect CRVC pipes and fittings. APVC pipes and fittings are used for hot water lines.


  • Don’t over-tighten plastic fittings, the threads are tapered, and this can cause the female fitting to split. Hand tighten fittings and then give an additional turn or two.

If you have any other issues or problems call 24 hour plumbers on 1300 896 508


Read More:

24 Hour Plumbing Service - Emergency Plumbing Service - Call 1300 877 448