A Wet Patch in the Lawn: Leaking Water Pipe or Poor Drainage?

Does the patch follow rain or watering?

Think back to when you first noticed the soft ground. If it appears after rain and gradually dries, surface drainage or runoff may be involved. If it remains wet without rain, a supply leak or irrigation fault becomes a stronger possibility. Neither pattern identifies a particular pipe on its own.

Check the irrigation controller’s normal schedule and whether a garden tap has been left running. Do not assume a wet patch beside a sprinkler is harmless: a connection may be leaking beneath it. Tell us whether watering was recently installed, repaired or switched back on after a break.

What a meter comparison can tell you

Sydney Water’s leak-detection advice identifies unusual green lawn patches as a possible sign of an underground leak. A meter comparison can add useful evidence where the property has an accessible individual meter.

Choose a period when nobody needs water. Account for toilets refilling, appliances and automatic irrigation, then record the meter reading and time. Compare it after a period with no expected use. Unexplained movement warrants investigation, but it does not prove the lawn patch and water loss have the same cause.

In strata or a property with shared supplies, explain the arrangement before interpreting readings. Rainwater tanks and separate irrigation feeds can also complicate the picture. Our guide to water leak detection in the Hills District explains the service to book when the source is uncertain.

Useful details to collect safely

• When the wet area first appeared and whether it is expanding.
• Recent rain, irrigation times and any visible nearby runoff.
• Changes in your water bill or normal tap performance.
• Recent landscaping, fence work or digging near the patch.

A wide photograph with a fixed reference, such as a path or fence, helps explain the location. Keep children, pets and vehicles off soft or unstable ground. If the water smells like sewage or comes with drain backup, say so when calling and avoid contact rather than treating it as clean water.

Why we establish the source before digging

Digging at the wettest point can miss a fault because water travels through soil. Testing should help narrow the likely source and distinguish supply plumbing from drainage. Access, pipe material and the location of existing fittings influence which investigation is practical.

If excavation is needed, the plan must account for buried services. SafeWork NSW’s excavation guidance requires underground service information to be obtained before excavation work. A garden spade is not a substitute for checking what lies below.

Ask the quote to separate investigation, repair and reinstatement of lawn or paving. That makes it easier to understand what is confirmed, what remains uncertain and what happens if the pipe follows a different route from the available plans.

Use the weather pattern to direct the booking

Record whether the patch dries between rain events, whether irrigation operates nearby and whether metered use continues when expected uses are off. These clues can distinguish the starting point for a supply investigation from a drainage assessment. Neither lush grass nor a puddle alone identifies a broken pipe, so keep excavation decisions until the route and source are better established.