The clearest signs gutters are blocked are water spilling over the edge in rain, stains on the wall below, plants growing from the channel, and a downpipe that stays dry in a downpour. If you spot any of these, clear the gutters soon, before overflow soaks the walls and fascias.
Signs you can spot from the ground
You do not need to climb a ladder to find out whether your gutters need attention. A short walk around the house, ideally in light rain, tells you a lot. Standing back with a coat on gives you the best view, because a blockage shows up while water is flowing.
Water overflowing during rain
This is the classic sign. In a normal shower, water should run along the gutter and out of the downpipe. If it pours over the front lip, drips from a joint or cascades from a corner, something is stopping it getting away. Our guide to why gutters overflow goes through the possible causes.
Dry downpipe while it is raining
If the rest of the system is busy but one downpipe stays dry, that run is probably blocked above it, or the outlet is clogged. Conversely, a downpipe that gushes at the bottom and splashes everywhere may be blocked or broken near the base.
Stains and green streaks on walls
Dark or green streaks beneath the gutter mark where water has been running down the wall instead of through the pipe. Peeling paint, damp patches, and algae at the same spot every year are strong indicators.
Plants and debris visible at the edge
Grass, weeds, moss or small saplings growing out of the gutter tell you there is plenty of soil-like sludge inside. You may also see leaves hanging over the front or twigs poking out of the outlet.
Sagging, tilted or pulled-away sections
The weight of wet debris pulls on brackets. If a section dips or sits at an odd angle, it may be holding water, which in turn causes overflow and leaks. See our article on sagging gutters for causes and fixes.
Signs inside and around the house
Sometimes the signs gutters are blocked show up indoors or at ground level before you notice anything on the roofline.
- Damp or mouldy patches on internal walls or ceilings near external walls.
- Peeling paint or dark stains on fascia boards and soffits.
- A musty smell near the eaves, or birds and insects clustering at the gutter.
- Pooling water or soggy ground along the base of the wall after rain.
- Splash marks and soil on the lower brickwork or window sills.
These can have other causes, but they are worth connecting to the gutters first. The relationship between overflow and damp is covered in can blocked gutters cause damp.
What each sign usually means
Not every symptom has the same cause, and a few can be confused with other problems such as a failed joint or a cracked section. This table helps you match what you see with the most likely explanation.
| Sign | Likely cause | What to do |
|---|---|---|
| Water over the front lip | Debris in channel or outlet | Arrange a clean |
| Dripping at a joint | Failed seal or blockage at the joint | Clean, then check the joint |
| Dry downpipe in rain | Blocked outlet or downpipe | Clear from above and below |
| Plants growing in gutter | Long-term sludge buildup | Full clean, then inspect for damage |
| Sagging run | Weight of debris or loose brackets | Clean, then refix or repair |
| Damp stains inside | Prolonged overflow or leak | Clean promptly and have the building checked |
What to do if you think they are blocked
Knowing the signs gutters are blocked is only half of it; the next step matters just as much, and acting quickly keeps it a small job.
- Look from the ground. Use binoculars or your phone camera on zoom to see the debris and joints.
- Take photos. They help you track the problem and make quoting simple.
- Do not climb up in wet or windy weather. Ladders are a leading cause of household injuries. Work above a single storey is best left to professionals.
- Arrange a professional clean. It is faster and safer than a DIY attempt, and the camera on our pole shows exactly what is inside.
- Ask for a check afterwards. Once the channel is clear, any cracked joints, loose brackets or poor falls are easy to spot.
If you are wondering how often to schedule this, read how often gutters should be cleaned.
What if the downpipe is still blocked after cleaning?
We clear downpipes from ground level up. If water still backs up at the bottom, the blockage may be in the below-ground drain, which needs a drainage specialist. We can usually tell you quickly which side of the problem you have. See downpipe blocked underground for more detail.
How SuperClean Gutters can help
Our gutter clearing service uses a commercial gutter vacuum on high-reach poles that go up to 12 metres (about 40ft), with a camera to show you before and after. Hand-clearing from a ladder is used only where deep debris or outlets need it. We clear gutters across Sunbury-on-Thames, Ashford and Hersham, plus everywhere on our areas we cover page.
Once the gutters are clear, if a joint is cracked or a bracket has failed, we also offer gutter repairs using new parts. Our team is fully insured and our work is backed by a service guarantee.
Call or WhatsApp 07368 590868 or send photos on WhatsApp for a free quote.
Frequently asked questions
How do I know if my gutters are blocked?
Watch them during rain. Water pouring over the front, dripping from joints, or a downpipe that stays dry are all strong signs. Other clues include green streaks on the wall, plants growing in the channel and sagging runs. Photos from the ground are usually enough for a professional to confirm.
Can gutters be blocked without overflowing?
Yes. A partly blocked gutter may cope with light rain and only overflow in heavy downpours. Debris can also build up slowly over months. Staining, sagging or plants in the channel can show a problem before overflow becomes obvious, so it is worth checking after each season.
What happens if I ignore blocked gutters?
Water overflows onto walls, fascias and the ground, which can cause damp, rot, stained brickwork and weakened fixings. Frost can crack wet gutters, and standing debris attracts pests. Dealing with blockages promptly is much cheaper than repairing the damage that builds up over several seasons.
Can I unblock gutters myself?
You can from a safe, stable position at ground floor level, but ladders are risky, and gutters above a single storey are best left to professionals. Never lean out from a ladder or work in wet or windy weather. A pole-based vacuum from the ground avoids most of the dangers.
