French Drain Case Study on Runoff Management in Shellharbour

Resolving Water Ingress Challenges in Shellharbour

In Shellharbour, a homeowner confronted a critical and worsening issue with water ingress. Water from two adjacent properties, positioned at a higher elevation, began to flow into their garden and infiltrate beneath the foundation of the house. This water intrusion caused substantial damage to the flooring, promoted rising damp, and led to mould growth within the property, jeopardising recent renovations.

How Can You Identify Signs of Water Intrusion?

The issue arose from both surface runoff and subsurface water flowing downhill from the back and side yards of nearby properties. Without an effective drainage solution to intercept this water, it inevitably made its way beneath the house.

Constructing a Reliable Drainage System

CS Plumbing designed and installed a gravity-fed French drain system aimed at capturing and redirecting water before it could reach the home’s foundation.

This initiative involved several key components:

A French drain system specifically designed to gather surface and subsurface water from neighbouring properties, effectively channeling it via gravity to a concrete pit.
A 100mm PVC pipe extending from the pit to the curb, featuring strategically drilled holes in the curb to ensure optimal water discharge.
Three new, larger-diameter Colorbond metal downpipes that replaced the original smaller versions, connected to new 100mm PVC piping leading to the curb.
A retaining wall system built along the boundary, employing concrete sleepers and galvanised steel posts, with auger holes drilled using an excavator to form a robust barrier against the adjacent yard.
Efficient soil removal conducted on-site with a dumper to ensure smooth management of the worksite.

What Effective Measures Can You Implement for Water Management?

The newly implemented system now effectively captures both surface and subsurface water at the property boundary, ensuring it is diverted away from the home. The homeowner has achieved a durable, low-maintenance solution that safeguards the foundation, flooring, and their investment in renovations.