Brisbane's intense summer downpours dump a lot of water in a short time, and your stormwater system has to move all of it. When a yard floods repeatedly, the water is either not entering the system, or not getting through it.
Common causes on the collection side:
- Surface grates and channel drains silted up with soil, leaves and lawn debris
- Downpipes disconnected from the stormwater line, discharging at the base of the wall
- Not enough collection points for the catchment area — water simply has nowhere to go in
- Ground levels or paving falling towards the house instead of away
Common causes in the pipes themselves:
- Stormwater lines packed with silt, sand and leaf litter (they carry debris-laden water by design and block gradually)
- Tree root intrusion — stormwater pipes are just as vulnerable as sewer lines
- Crushed or collapsed sections, especially under driveways
- Undersized or ad-hoc "handyman" drainage that was never designed for storm flows
Diagnosis follows the water: check what the surface drains and downpipes do in rain, then jet and camera the underground lines to see their condition. Fixes range from simple cleaning and jetting, up to new collection pits or replacing crushed pipe.
Persistent flooding against the house is worth fixing promptly — repeated saturation undermines footings, damages slabs and invites termites.