Signs roots are the problem
- The main drain blocks again and again, months apart.
- Several fixtures slow down together, and the gully outside fills.
- A large tree, hedge or palm grows near the line of the sewer pipe.
- The house is older and its drains are clay.
- A plumber has pulled roots out on the cutter before.
Why roots get in
Old clay sewer pipes were laid in short lengths with joints between them. Over the years those joints shift and crack, and the moisture inside draws fine roots through the gaps.
Once in, roots thicken and spread into a mat. Paper and waste snag on it until the drain stops. Plastic pipes with sealed joints are harder for roots to enter, though a crack or a poor joint can still let them through.
What a plumber will do
Confirm it's roots
Run a camera to see where they enter and how far the damage goes.
Cut them out
Clear the pipe with a root-cutting head on a drain machine or a jetter.
Look again
Film the cleared pipe, because roots often hide cracks and joints that have pulled apart.
Seal the entry points
Recommend a lasting fix: relining the damaged run, or replacing the worst sections.
Cutting versus fixing
Cutting roots is maintenance, not a cure. The gaps they came through are still there, so they grow back, and each round of regrowth can open the joint a bit further.
A liner seals the inside of the pipe along its length, which takes away the joints roots use. Where the pipe has collapsed, digging up and replacing that section is the other route.
Taking the tree out isn't a fix on its own: the roots already in the pipe still need clearing, and the cracks still need sealing.
Whose roots, whose bill?
Roots in your part of the pipe are yours to deal with, and some water companies spell out where their part starts. Sydney Water says the owner is responsible for clearing tree roots that enter the junction at the point of connection.
Root clearing can also rule out a refund. On South East Water's list of cases where the owner pays: "Tree roots were cleared". Other companies differ: see who owns the sewer pipe.
What changes the job
- How many joints are letting roots in, and how far along the pipe.
- Whether the pipe is cracked as well as invaded.
- How easy it is to reach the line from an inspection opening.
- Whether the tree is staying, so the roots will keep trying.
What you can do, and what to leave
You can
- Note where trees, hedges and palms sit in relation to the drain line.
- Plant new trees well away from the sewer line, and ask the nursery how far the roots spread.
- Book a camera inspection after the second root blockage, rather than waiting for a third.
- Ask before pouring any root treatment down the drain, and tell the plumber if you already have.
Leave to a licensed plumber
- Cutting roots, by drain machine or jetter.
- The camera inspection and finding the entry points.
- Relining or replacing damaged pipe.
- In WA, root cutting isn't on the homeowner list, where the only blockage job is plunging a blocked fixture or waste pipe.
Licences and paperwork
Cutting roots out of a sewer is drain work. In WA, any sanitary or drainage plumbing not on the homeowner list "must be carried out by a licensed plumber or permit-holder".
If the fix becomes a liner or new pipe, paperwork follows. In NSW, the Certificate of Compliance for drainage work comes with a Sewer Service Diagram, and the plumber has to give you a copy. Licence checks for every state are on the main blocked drains page.
Questions to ask about roots
- Where are the roots getting in, and how many entry points are there?
- Is the pipe cracked, or is it just the joints?
- Would relining stop them, and which sections would you line?
- If I only cut them this time, how soon should I expect them back?
- Is any of the damage on the water company's side?
What we would do
If roots have blocked the drain twice, stop paying only to have them cut. Get the camera footage, find out how many joints are letting them in, and weigh a lasting fix against more call-outs. A drain specialist who does both cutting and relining will show you each option on the footage.