Trees & Infrastructure

Tree growth is typically influenced by below-ground conditions. Tree roots are opportunistic and will proliferate wherever moisture, aeration, nutrition, and soil structure support growth.

Trees can contribute to infrastructure damage directly, by exerting pressure on a structure, and indirectly, through altering the soil moisture in the area adjacent to a structure. Often there are multiple factors contributing to infrastructure damage and are seldom associated with tree root growth alone. For this reason, claims of indirect tree root damage must be accurately investigated.

Tree roots can sometimes inadvertently impact sewer and stormwater pipes. It is important to establish the cause of the problem and who is responsible for rectifying it. Leaking pipes (due to poor construction, old earthenware, cracked and faulty joints and degradation) can create a moisture gradient that encourages tree root growth in the direction of the pipe.

All concerns that a Council managed tree is contributing to infrastructure damage will be investigated by Hobsons Bay City Council. Please notify Council of your concerns by completing a Tree Service Request or by contacting our Customer Service Team on 1300 179 944. Depending on the situation, you may be required to submit a structural engineer’s report that verifies the concern.

When reviewing a claim that a tree is contributing to infrastructure damage, Council will explore all viable options to retain the tree before considering removal. 

Trees and infrastructure FAQ 

Who is responsible for the services of a private property?

A property owner is responsible for the services to their property. This includes sewer and stormwater pipes and services that run through or adjoin private and public land until they reach infrastructure drainage points, such as, sewer mains, street gutters or stormwater pits. 


What causes my pipes to leak?

The most common cause of pipe leakage occurs in old terracotta pipes. Movements in the surrounding soil cause joint failure or cracking causing moisture and nutrients to leak into the soil. Failure of joints between PVC and terracotta pipes is also common. PVC pipe systems have fewer joins and tend to be more reliable.

It’s important to consider repairing or replacing old infrastructure. Many properties in established areas have undergone several bathroom and kitchen renovations, but the original sewer and stormwater system may remain. Upgrading and maintaining essential infrastructure is an important part of owning a property. 


How can trees and their roots impact my services?

Tree roots grow wherever conditions are favourable. When tree roots encounter water or nutrients they will grow with increasing concentration. Tree roots will usually enter pipes that have a fault, which allows the tree to access the available water, nutrients and oxygen.

Tree roots can enter services via leaking joints and blocked pipes, through deteriorated seals, where the joint has failed or been dislodged or through previous damage. It is rare for a tree root to crack into a properly installed and well-maintained pipe. Once a pipe has deteriorated or is damaged, roots from all different types of trees, plants and even grasses can grow in the pipe. 

How can I prevent tree root damage to my services?

The best way to protect your property against potential issues with tree roots is to ensure the proper maintenance of pipes. The most efficient way to prevent root damage to your services is to replace any old terracotta pipes with new PVC or UPVC ones and use pressure seals. Other methods include the type and compaction of the backfill around these services, which help prevent root growth in these areas. 

I think damage to my pipes is caused by a tree on council land, what do I do?

Where possible you should carry out the repairs and ask us to investigate. If Council-owned trees have caused the initial damage to the pipe, you may be able to claim for the cost of the repairs.

In any event, it is best if you:

  1. Obtain several written quotations for the necessary repairs.
  2. If the works require an excavation on a council road or footpath, you will need to obtain a road-opening permit from Council.
  3. Carry out any necessary repair work to avoid any further damage and/or reduce the hazard.
    This does not mean Council has accepted any liability for damages. It is the property owner’s decision to carry out repairs.
  4. Most importantly, notify Council of the scheduled works so that Council can arrange for an appropriate officer to inspect the exposed pipe during the works. This will enable all parties to confirm if council tree roots have caused the problem or if the pipe has been damaged for some other reason.
  5. While on site, the Council officer will take photos to keep on record. You should also keep your own records of the damage and repairs. If the above investigations reveal the damage has been caused by council owned trees, you can fill out an Incident Notification Form to see if you  cost of repairs.

Include all the above information in your claim and address it to the Insurance Officer at Hobsons Bay City Council. Council will assess liability and decide if we can assist you with the cost of the repairs. 


Why does Council take this approach?

This approach is required for insurance and governance purposes because the works relate to a private asset and may involve spending public funds on the repair. It is important to have clear evidence for any insurance claim, particularly if there is a chance the initial damage may have been the result of other causes.