Quick answer
Why do gutters overflow after being cleaned?
Because the water still has nowhere to go. The four usual causes are a blocked downpipe, a blocked underground drainage gully at the base of the downpipe, a sagging gutter run with the wrong fall, or a failed joint or bracket letting water out before it reaches the outlet.
Work through it in this order
- 1
Gutter clear?
Confirm with camera footage, not from the ground.
- 2
Downpipe flowing?
Pour water in the top, if it backs up, the pipe is blocked.
- 3
Gully clear at the base?
Underground gullies silt up and back the whole system up.
- 4
Correct fall along the run?
Water should move towards the outlet, not pool mid-run.
- 5
Joints and brackets sound?
A dropped bracket creates a low spot that always spills.
Only the first two are cleaning jobs. The last two are repairs.
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