Most people are taken aback at the first sighting of woodlice in their home. Even though these little pests may be completely harmless, they are hardly desirable.
Woodlice are usually harmless, but repeated sightings indoors nearly always point to a moisture issue (condensation, damp or a small leak) that's worth fixing. In our experience, the homes most prone to it are older, damper properties – they tend to hold more moisture and have more of the tiny gaps woodlice slip through. And the common thread in almost every case is the same: people focus on the woodlice they can see while overlooking the damp that's actually drawing them in. Fix the damp, and the woodlice problem usually goes with it.
This article discusses the most common causes of woodlice indoors and answers the common question: why do I get woodlice in my house?
📋 Quick answer: why you get woodlice indoors
- It's almost always moisture – condensation, a small leak, or general damp – combined with an easy way in (gaps, air bricks, thresholds).
- Older, damper houses are the most prone, as they hold more moisture and have more tiny gaps to exploit.
- The usual mistake: treating the woodlice you can see while ignoring the damp that's pulling them in.
- Do this first: dry the area (ventilate and fix leaks), clear damp organic material outside, then seal entry gaps.
Common Causes of a Woodlice Infestation
There are various reasons why you may stumble across woodlice in your home. Here are the most common ones we come across, along with our suggested solutions.
1. Damp Areas in the Home
Woodlice thrive in moist, humid environments. In the home, that typically means basements, bathrooms, kitchens and garages, where the available moisture is often ideal for woodlice to establish a presence and multiply. It's also why sightings tend to climb through the wetter, colder months, when it's damper both indoors and out.
We recommend using dehumidifiers in areas known to be damp. Fix any leaks promptly, and regularly check that extractor fans – including those in bathrooms and kitchens – are running effectively.
Common hidden cause: blocked gutters and downpipes, and damp walls, can keep a room cooler and wetter, which makes it much easier for woodlice to survive indoors. Check your guttering and any damp patches on the external wall near the problem room.
2. Rotting Material
Woodlice are also attracted to decomposing organic matter in and around your home – wood, leaves and other materials they feed on. Outside, you'll often find them under soil, rocks, logs, plant litter and compost heaps. Some will even be drawn to damp paper products, vegetable peelings and plant material kept indoors.
We recommend regular maintenance to limit decaying material: cut the grass, prune plants and trees so growth doesn't get out of control, and remove any decaying vegetation and organic debris.
3. Entry Points
Woodlice enter through cracks and crevices around windows, doors and pipes, which may only be a few millimetres in size. Common routes include air bricks and vents, gaps under external doors (thresholds), and small openings around pipework and cable entries. Older properties can be more prone simply because there are more tiny gaps to exploit – which is a big part of why older, damper homes see the most woodlice.
Poor sealing of these gaps in foundations and walls gives them easy access into your living space.
We recommend regular inspections for possible entry points, looking especially for cracks and small gaps around windows, doors, floors and pipes. Seal these areas thoroughly to prevent woodlice from entering – though it's worth drying the area out first, as sealing alone won't remove the damp that's attracting them.
4. Indoor Plant Material
Indoor plant material, such as potted plants, can be a magnet for woodlice, especially if the soil is moist. Overwatered pots in particular are attractive, as they're a source of both moisture and organic matter for woodlice to feed on.
To reduce the risk, be mindful of your watering habits and avoid overwatering. Check plants regularly for signs of pests, remove any fallen leaves or plant debris promptly, and where possible place potted plants in well-ventilated areas to reduce moisture build-up.
5. Poor Ventilation
Stagnant air and poorly ventilated spaces create the perfect humid conditions for woodlice to thrive. Basements, attics and storage rooms are common culprits, as they typically lack the airflow that lets moisture escape.
To combat this, make sure each room has proper ventilation. Install or maintain extractor fans in key areas like bathrooms, kitchens and basements. Where natural ventilation is limited, consider air circulators or dehumidifiers to keep air moving and reduce moisture levels. Inspect these areas regularly for trapped humidity and improve air circulation where needed.
Final Word
We've shared the most common reasons for getting woodlice in your home, along with solutions. Early identification and prompt action are key – but the single most useful thing you can do is treat the root cause, which is nearly always damp, rather than the woodlice themselves. Regular cleaning, maintenance, damp reduction, ventilation and sealing off entry points will all reduce the risk.
You may also want to use sticky traps to monitor activity levels, and a food-grade natural powder such as diatomaceous earth as a gentle, low-toxicity option in dry cracks and along edges – bear in mind it only works while completely dry, so it's of limited use in the damp spots woodlice prefer. If woodlice keep appearing despite drying and proofing, that usually points to an ongoing damp source worth having looked at; a damp specialist, or a professional you can find via the BPCA directory, can help.
We go to great lengths to ensure that all our DIY woodlice control products are effective, fast and easy to use. You may also find our expert guide to getting rid of woodlice useful if you want to learn more about clearing them from your home or workplace.
