Sewer Relining Program

To continue to deliver safe and reliable sewerage services, Unitywater is conducting an ongoing program to improve the condition of our sewer pipes and manholes that form part of our sewer network.

Why is this needed?
This planned renewals work helps maintain the integrity of our pipes and manholes. Damaged or degraded pipes and manholes allow groundwater (infiltration) to enter the sewer network, which causes capacity strain on our system. By reducing infiltration we can better manage sewage flows, especially during storm and heavy rain events, helping us to protect the health of the community and the environment.

Why are contractors used?
The nature of this work requires specialised equipment, skills and experience. Our rigorous tendering process ensures that we choose the most cost effective and best equipped contractors to complete these tasks.

What’s involved?
Firstly, special cameras (CCTV) are used to identify sewer mains pipes that are damaged or degraded. Targeted pipes are then repaired using innovative relining techniques to correct faults, rather than being replaced. This is a no-dig and cost-effective way of renewing the pipe.

In most cases, circular pipe-liners are formed on site by taking a continuous strip of plastic and spirally winding it inside the damaged host pipe, forming a water-tight pipe within your pipe.
Where this method is not practicable, cured in place pipe is used. This involves inserting a liner into the pipe, which is then hardened in place using steam or hot water – again, becoming a pipe within your pipe.

Any water used during the relining and flushing process is either supplied by the contractor, or accessed via a hydrant using a Unitywater metered standpipe. Water does not come from the property’s water supply.

Manholes are visually inspected for signs of deterioration and, if required, a special coating is applied to restore these to original condition.

What are the benefits?
Relining pipes and resurfacing manholes has many benefits including:
• Helps protect the environment and community health by preventing groundwater from entering and overloading the sewer system;
• It’s more cost effective to renew rather than replace infrastructure;
• Low impact works using trenchless technology ;
• Minimal disruption to sewerage service; and
• Defers the need for expensive infrastructure replacement.

What are the impacts?
By using relining technology we minimise service disruption and limit soil disturbance. In the unlikely event that excavation is required we notify customers and any disturbed areas are restored on completion of the work.

Depending on which relining procedure is required, sewerage services may be interrupted for at least two hours. There may also be minor noise impacts, but these are kept within acceptable guidelines. You will be advised of this prior to the work commencing.

To complete manhole works, sewerage services need to be interrupted for a minimum of four hours.

What do I need to do?
While we are relining pipes and restoring manholes we ask that you limit your household water usage by only using water for vital activities such as toilet flushing. Please do not use dishwashers, washing machines, baths or showers, or leave taps running during this time.

How will I be notified of work?
Affected residents will be notified of planned works in writing at least 48 hours in advance.
Our contractors always aim to speak with the resident before carrying out works on the property, and will leave a notification card in the letterbox if the resident is not at home. We’ll also leave a card to let you know when the work is completed.

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