Sewerage pipes are at greatest risk from the roots of plants because, unlike water pipes, they are unpressurised. Because of this, the roots of plants can quickly grow into the pipes if a crack or other fault occurs.
When planting, the aim should be to keep any medium to large trees well away from the pipelines. As a tree grows, its roots expand and thicken and this causes stresses within the soil. If a sewer pipe is in the vicinity, the stresses can cause compression or movement of the pipe, leading to cracks or broken joints. Once the integrity of the pipeline is broken, any plants, even grasses, can cause blockages.
All trees and many large shrubs are a potential risk to sewerage pipes so they should be planted at least 4 metres away from the pipe's alignment. The trees and other plants listed below are common examples of species with particularly vigorous root systems and they should be at least 10 metres from underground pipes. Note, however, that the list is not comprehensive - for further information refer to the Fact Sheet published by Western Water, Victoria.
Know what's underground before planting!!
|Botanical Name||Common Name||Botanical Name||Common Name|
|Acer negundo *||Box elder *||Allocasuarina and
|She oaks, river oak, forest oak|
|Angophora species||Large species||Araucaria species||Hoop, bunya and Norfolk pines|
|Black bean||Corymbia species||Large gum trees|
|Eucalyptus species||Large gum trees||Ficus species||Figs|
|Grevillea robusta||Silky oak||Jacaranda mimosaefolia *||Jacaranda *|
|Liquidamber *||Lophostemon confertus||Brush box|
|Broad-leaved paperbark||Melaleuca styphelioides||Prickly paperbark|
|Platanus acerifolia *||Plane tree *||Populus species *||Poplars *|
|Quercus species *||Oaks *||Salix species *||Willows *|
|Schinus molle *||Pepper tree *||Schefflera actinophylla||Umbrella tree|
* indicates an exotic species