Tree roots are normally the cause.
During long dry periods the root systems ‘sense’ even the smallest traces of moisture, and will seek out the source. When you get a long dry spell, followed by regular heavy rain as we do in autumn, the roots grow quickly and invade pipes. Any foreign matter that is then flushed through the pipes then gets snagged on the roots, and blockages form.
Blocked drains can be cleared relatively easily most of the time, but they will continue to come back until a permanent solution is found.
There have always been two permanent solutions to this problem. The first is to remove the trees, and the second is to replace your existing pipes with new PVC pipes. Both of these solutions can cause a lot of upheaval to your backyard and for people with established gardens and landscaping they can be a real pain.
There is a third and relatively new option though – pipe relining.
A fairly new weapon in the plumber’s arsenal relining root-damaged, cracked, or collapsed earthenware pipes brings your sewers or stormwater back to looking like new. A resin is inserted inside the existing drains with no need to dig up your whole yard. Once the resin hardens it leaves your old pipes ‘relined’ with a completely new pipe.
Relining isn’t always the solution, but it can save you a lot of time and worry. Give your local plumber a call and ask them if relining is right for you.