Everyone thinks about the gutter. Almost nobody thinks about the pipe it drains into.
Which is a shame, because a blocked downpipe causes more damage than a blocked gutter, is harder to spot, and takes about ten minutes to fix if you catch it.
The test that takes thirty seconds
Wait for proper rain — not drizzle, actual rain. Then go and stand at the bottom of each downpipe.
Water should be coming out. A steady flow at the bottom, running away into the gully.
If the gutter above is clearly full and the downpipe is bone dry, the blockage is in the pipe, not the gutter. That’s the whole test.
There’s a second version for dry days: knock the pipe with your knuckles, from the bottom upwards. An empty pipe sounds hollow. When the note goes dull and solid, you’ve found the top of the blockage.
Why the pipe blocks and the gutter doesn’t
A gutter is wide and open. Debris spreads out along it and water still gets past. It has to be genuinely packed before it stops draining.
A downpipe is about 68mm across and it has corners. A single clump of moss that would sit harmlessly in a gutter for years will wedge at the first bend and stay there. Then everything else stacks up behind it.
Round here the usual culprits are:
- Roof moss. Sheds constantly off concrete tiles, slides down with the rain, and packs solid. This is the number one cause on North Lanarkshire houses.
- Render grit. Pebbledash and harling shed fine stone for their entire life. It behaves like wet sand — heavy, and it sets hard in a bend.
- Nests. Usually at the top, usually spring, usually in the swan-neck bend.
- Leaves, last. Genuinely fourth on the list here, whatever the internet says.
The three places it jams
The swan neck. That double bend at the top where the pipe steps in towards the wall. Gravity stops helping and anything solid parks there.
Behind a bracket. Where the pipe is clipped tight to the wall it can bow very slightly inwards. Not enough to see, enough to catch moss.
The shoe at the bottom. The curved bit that kicks water out into the gully. It fills from the bottom up with silt and leaf mulch, and it’s the easiest one to check because you can see straight into it.
Start at the bottom. It’s the most common and the quickest.
What it actually costs you
A gutter that overflows is annoying. A downpipe that’s blocked is expensive, because the water has nowhere to go and it goes down the wall instead — continuously, in the same place, for months.
That gives you, roughly in order:
- A green or black stripe down the render. Cosmetic at first.
- Saturated wall. Render and brick that never dry out.
- Damp inside. Usually a patch on an upstairs wall in late winter, from a blockage that formed in autumn.
- Frost damage. Water in the render freezes, expands, and blows the surface off in flakes.
By the time you can see the third one from inside, you’ve been paying for the second for months.
Can you clear it yourself?
Sometimes, and safely, if it’s the shoe at the bottom — hand in, glove on, pull out the sludge. That’s a perfectly reasonable Saturday job.
For anything higher up: please don’t get a ladder out. Downpipe blockages are almost always at the swan neck, which is at gutter height, which is the exact height that puts people in hospital. A ladder against a wet gutter on soft ground in Scotland is a genuinely bad plan.
I clear from the ground with a vacuum system and a camera, so nothing leans on your gutter and I can show you what came out.
How I do it
Gutter first, so I’m not pushing debris down into the pipe. Then the downpipe from the top, then a flush from the top with the shoe watched at the bottom — because a pipe that’s been rodded isn’t proven clear until water has run through it end to end.
Camera footage before and after if you want it. Most people ask for it once, then never bother again, which is fine — the point is that it’s there if you want to see it.
What it costs
- £20–30 per side of the house, downpipes flushed and checked as part of it
- Typical two-sided semi: £40–60
- Larger detached with four runs: £80–120
Downpipe checking isn’t an extra. It’s part of clearing a gutter properly — a gutter that drains into a blocked pipe hasn’t been cleared, it’s just been tidied.
If your gutter is overflowing and you’ve already had it cleaned this year, it’s the pipe. Send me a photo and your postcode. 07440347383