French Drains and Subsurface Drainage Wollongong

French Drains for Groundwater and Landscaping Drainage

If water sits on your lawn after rain, your subfloor smells damp, or a retaining wall is weeping, a French drain is usually the fix. It’s a gravel-filled trench with a perforated pipe that collects groundwater and carries it away to a legal discharge point, a stormwater connection, a soak pit, or a lower part of the block.

We’ve been installing subsurface drainage across Wollongong and the Illawarra for over 30 years. The difference between a French drain that works for decades and one that clogs in two winters is in the parts of the job you can’t see: the fall on the pipe, the grade of aggregate, and where the water is actually sent. That’s the part we get right.

What a French drain does (and when it’s the right call)

A French drain manages groundwater and surface water, the slow, spreading kind of wet, not a blocked sewer. It’s the right solution when you’re dealing with:

• Lawn or garden beds that stay soggy for days after rain
• Water pooling against the house, a shed, or a retaining wall
• Rising damp or a musty, damp subfloor
• A saturated slope or a garden that drains onto a neighbour’s block
• Paving or a driveway that sheets water toward the building

If the problem is a blocked or slow drain inside the property instead, that’s a different job, see our blocked drains and stormwater drainage pages, or just call and describe what you’re seeing.

How we install a French drain

Every site drains differently, so we start by working out where the water comes from and where it can legally go, then build to suit.

1. Site assessment & drainage design.: We check levels, soil, and the existing stormwater layout, and plan the run so water moves away from the building, not around it.
2. Excavation.: We dig the trench to the depth and fall the site needs, too shallow and it won’t collect, too flat and it won’t flow.
3. Pipe, aggregate & geotextile.: Perforated pipe wrapped in a filter sock, bedded in clean drainage aggregate and wrapped in geotextile fabric so soil and silt don’t choke it.
4. Legal discharge.: We connect to stormwater or an approved dispersal point so the water leaves the property the way it’s meant to.
5. Reinstatement.: Backfill, tidy the surface, and leave the site clean.

Residential and strata sites both, from a single soggy backyard to drainage across a townhouse complex.

When a French drain isn’t enough on its own

Sometimes the surface fix sits on top of a deeper problem. We’ll tell you if that’s the case rather than bury it. Signs the ground needs more than a trench:

• An existing drain has collapsed or been crushed by ground movement
• Tree roots have got into and lifted the pipe run
• The original system is badly undersized for the volume of water
• Excavation is needed to reset falls that were never right

Where that’s the case we quote the excavation and repair work separately and explain why, no surprises.

Why Wollongong locals call CS Plumbing for drainage

Get your French drain sorted

Tell us what you’re seeing, where the water sits, how long it stays, and what it’s threatening, and we’ll arrange a site inspection and a clear quote. Servicing Wollongong, the northern suburbs, and the wider Illawarra.

Get in touch with CS Plumbing & Drainage Services