You spot some dark marks on the wall near your window sill. They weren’t there last week, and they don’t look like dust or mould. Maybe you clean them up, but they come back. Could it be mould? Fly spots? Or something else? One of the most overlooked signs of spider activity in your home is actually their droppings — something most people don’t even realise spiders leave behind.
If you’ve been finding small black smudges or strange droppings in quiet corners or on the walls, there’s a good chance you’re looking at spider waste. In this guide, we’ll go through exactly what spider droppings look like, where to find them, why they matter, and how you can deal with them properly. Because once you know what you’re dealing with, it’s much easier to stay on top of it.
What Exactly Are Spider Droppings?
Spider droppings aren’t something most people think about — not until they see something odd and start wondering. But yes, spiders do leave waste behind, and it can show up more often than you’d expect, especially if you’ve got a few of them living in quiet corners of your home.
Do Spiders Really Poop?
Yes, they do. Just like other animals, spiders have to get rid of waste from their bodies. Their droppings are made up of substances like uric acid, guanine (which comes from breaking down proteins), and any leftover bits of the insects they’ve eaten. The waste is semi-liquid, which means it often comes out as a dark splatter or smear rather than a solid pellet.
So even though spiders are silent, tidy hunters, they’re not exactly spotless guests. They eat, they rest, and they leave waste behind — especially if they stay in the same spot for a while.
Why Spider Droppings Look Different to Other Pests
Spider droppings don’t look like what people usually expect from “poo.” You’re not going to see tiny pellets or visible lumps. Instead, you’ll notice dark, inky marks — usually black or very dark brown, sometimes with a slightly runny or dried edge. They can look a lot like ink splatters or flyspecks.
Because of this, people often mistake spider droppings for mildew, mould spots, or even soot. But they tend to appear in specific places — near webs, around ceiling edges, under windows, or on skirting boards — where spiders rest. If you clean the area and the spots keep coming back, chances are you’ve got spiders nearby.
Where You’re Most Likely to Spot Them
You’re most likely to find spider droppings in quiet, undisturbed parts of the home — places spiders choose to spin webs or stay still. Think about the top corners of rooms, behind curtains, under window sills, on ceilings, or around light fittings. Some spiders prefer basements or attics, while others stick close to warmth or light.
If you’ve got white walls or light-coloured surfaces, the droppings stand out more clearly. In darker areas, you might not notice them until they’ve built up. You might also see them on skirting boards, bookshelves, cupboards, or anywhere a spider likes to perch.
What Do Spider Droppings Look Like in Your Home?
Now that you know spiders do leave droppings, and they can show up just about anywhere a spider rests, it helps to get specific about what to look for. That way, you can spot the signs earlier and decide what steps to take next.
How to Visually Identify Spider Poop
Spider droppings usually show up as dark, irregular spots — not neat or shaped. They might look like small paint splashes or watercolour drips, and they can dry in a way that creates slightly raised, crusty edges. On a flat wall, it can look like someone flicked ink or dark paint.
The colour is usually black, dark grey, or deep brown. Sometimes, depending on the surface or the spider’s diet, the spots might have a reddish tinge or look oily. If you touch them (though it’s better not to), they’ll feel dry and flaky if they’re old, or sticky if fresh.
When to Suspect Spiders vs Other Insects
Other insects can leave behind spots too, but the shape and placement help you tell them apart. Flyspecks, for example, tend to be more scattered and rounded. Cockroach droppings are solid and shaped like small, dark pellets. Rodent droppings are even larger and more oval.
Spider droppings tend to be clustered around webbing or rest spots — not near food or waste bins. They look more like drips or stains than droppings. If you see webs nearby or know you’ve got spiders in that part of the house, it’s a safe bet the marks came from them.
Does the Type of Spider Affect the Mess?
Yes, it does. Larger spiders like wolf spiders or big house spiders produce more noticeable droppings simply because of their size. They also tend to stay in one place longer, which means more waste builds up in the same spot.
Smaller spiders, like cellar spiders or web-spinners, leave smaller marks, but they might build up faster in webs or along ceilings. The more active the spider, or the longer it stays in one place, the more visible the mess becomes.
Is Spider Poop Dangerous or Harmful?
Once you know what those dark spots are, the next thing most people ask is whether it’s something to worry about. While spider droppings aren’t known to be toxic, they’re not completely harmless either — especially if they’re left to build up.
Can It Pose Health Risks Indoors?
For most people, the health risk from spider droppings is very low. However, like any form of animal waste, they can carry bacteria or allergens — especially if they’re spread across surfaces where food is handled or children play.
People with respiratory issues or compromised immune systems might react to long-term exposure, especially if the droppings are left on air vents or near bedding. It’s always better to clean them up than ignore them, just to stay safe.
Is It a Sign of a Bigger Infestation?
Not necessarily — but it does mean there’s at least one spider making itself at home. And often, if you’ve noticed droppings, it means the spider has been there for a while. If the droppings show up in multiple areas or come back quickly after cleaning, it could point to several spiders or a regular food source attracting them.
Remember, spiders follow prey. If you’ve got a fly or moth problem, spiders won’t be far behind. Their droppings are a useful early warning sign that the food chain in your home might need attention.
Why You Shouldn’t Just Ignore It
Leaving spider droppings on surfaces for too long can cause stains — especially on painted walls, wood, or soft furnishings. Over time, they can leave behind permanent marks, and on porous materials, the dark residue can soak in.
Cleaning them up as soon as you spot them not only keeps your home looking cleaner but helps reduce the chances of attracting more insects or worsening any potential health impact.
How Can You Clean Up Spider Droppings Safely?
Once you’ve identified the droppings, the next step is dealing with them properly. It doesn’t take much, but doing it right helps prevent stains and keeps the space safe and fresh.
Best Cleaning Methods for Hard Surfaces
If the droppings are on hard surfaces like tiles, skirting boards, window sills, or walls, start with a damp cloth and a bit of mild soap. For fresher spots, that’s usually enough. For older, dried ones, you might need a mix of vinegar and warm water, or a light bleach solution if the surface allows it.
Spray the area, let it sit for a minute, then wipe gently with a clean cloth. Don’t scrub too hard, especially on painted walls — that might cause damage to the paint underneath.
How to Deal with Stains on Fabric or Paint
If you’ve got spider droppings on curtains, sofas, or bedding, blot the area gently first. Use cold water and a mild cleaner — you want to lift the mark without setting it deeper into the fibres.
Avoid rubbing. If the stain is stubborn, a mix of baking soda and water or a little upholstery cleaner might help. On painted surfaces, always test a small area first before using anything too strong. In some cases, repainting might be the only option if the stain won’t come off.
What Protective Gear (If Any) You Should Use
For light cleaning, gloves are usually enough. If you’re dealing with a larger amount — say, in an attic or basement — it’s smart to wear a dust mask, especially if there’s a lot of dust or other insect debris. Make sure the area is well ventilated, and wash your hands afterwards.
It’s better to be cautious than to assume everything’s clean just because it looks it.
How Do You Stop Spiders From Coming Back?
Cleaning up is only part of the solution. If you don’t want the same thing happening again, you’ll need to make your home a less attractive place for spiders to settle.
Seal and Remove Their Hiding Places
Start by sealing up cracks and gaps in walls, baseboards, and windows. Spiders love narrow, dark crevices. Remove old boxes, piles of clothes, or unused corners that give them shelter. The fewer places they can hide, the less likely they’ll hang around.
Keep Their Food Source Under Control
Spiders come where the food is — mostly other insects. If you’ve got flies, ants, moths, or other bugs getting in, spiders will follow. Keep your home tidy, cover bins, and deal with crumbs or spills quickly. Installing fly screens or sealing door gaps can help reduce insect traffic.
Use Deterrents Without Harming the Environment
You don’t need harsh chemicals to keep spiders away. Natural deterrents like peppermint oil, citrus, or eucalyptus sprayed near windows and corners can do the job well. Diatomaceous earth can be used in dry areas where insects travel. These solutions are safe for homes with kids or pets and don’t harm the environment.
When Should You Call a Professional?
Sometimes, spider droppings keep coming back no matter what you try. That’s when it’s time to bring in someone who can look deeper.
If You’re Seeing Droppings Frequently or in Volume
If cleaning the same area every week becomes routine, or if the number of droppings seems to be increasing, you might have more than a stray spider. A pest control technician can confirm whether it’s just spiders — or something else drawing them in.
If You Can’t Locate the Source or Nest
Spiders are great at hiding, and they don’t always leave webs where you can see them. Professionals know where to look and can find the entry points or hiding spots that you might have missed.
If Cleaning Isn’t Enough to Solve the Problem
If you’ve cleaned, sprayed, sealed, and the problem continues — it’s time to go beyond DIY. Pest control can provide a targeted, safe treatment that removes both spiders and the insects attracting them.
Our Final Say
Spider droppings might not be the most talked-about topic, but they’re one of the clearest signs that spiders are sharing your space. Once you know what to look for, they’re easy to spot — and even easier to manage if you take action early.
From recognising the marks to cleaning them safely and stopping the cycle, it’s all about staying informed and being proactive. And if it ever gets too much to handle on your own, help is always just a call away. Because a clean, spider-free home isn’t just nicer to live in — it’s peace of mind, too.
