Why do tree roots keep blocking my Toorak sewer line?
Because roots are not attacking the pipe — they are following moisture. Old earthenware clay sewer lines, which are common under Toorak’s older homes, have joints every metre or so. As those joints age they weep slightly, and nearby tree roots grow towards the moisture and work in through the gap. Once inside the pipe they find constant water and nutrients and keep growing. Clearing the roots restores flow, but unless the entry point is repaired or relined, they will return — usually within one to two years.