What causes leaks and breaks?

• How does Sydney Water manage leaks?
• How can I check for leaks?

Changes in rainfall, temperature, soil type, water pressure and ground movement can all cause leaks or lead to a water main break.

To find leaks and help prevent breaks, Sydney Water will inspect up to 12,000km of pipes in 2011/12. Sydney Water's Leak Reduction Program saves about 30 billion litres a year. That's enough to supply 150,000 households. We do this by:

• actively searching for and repairing leaks
• quickly responding to leaks reported by customers
• replacing pipes
• linking rainfall and soil moisture levels to leak repair plans
• reducing pressure in the pipes

Finding and repairing leaks

Sydney Water uses world's best practice to find and repair hidden leaks and reduce the amount of water lost through underground leaks. To look for hidden leaks, in most cases we use acoustic devices that pick up the noise water makes as it leaks from a pipe.

Replacing pipes

About 90 per cent of leaks and breaks in our system are in cast iron pipes.  This is because the structure of cast iron changes over time. It becomes brittle through chemical reactions with soil and water. The joint type is also a factor.

Cast iron pipes stopped being used in the 1980s. We are now replacing old cast iron pipes with more flexible, long lasting material like ductile iron, steel and polyvinyl chloride (PVC).

Linking rainfall and soil moisture to leak repair plans

Different types of soil expand and contract depending on the level of moisture in the soil.

For example, clay soil dries very quickly in high temperatures. It may cause the ground to move which can lead to cracks in the pipe.

Sydney Water uses information about soil moisture and rainfall to plan the way we replace pipes.

Reducing pressure

Excessive water pressure can cause pipes to break and can also lead to leaks in Sydney Water's and the customer's system. Through managing water pressure, we reduce the number of water main breaks and leaks, improve the reliability of the water supply system and save water. Learn more