HOME PEST PREVENTION
Woodlice and slaters in Sydney after a wet week: why they head indoors
After several days of spring showers across Sydney, small grey crustaceans start appearing in bathrooms, laundries and along door thresholds. They are harmless, but they are a useful signal that moisture has built up close to the house.
Woodlice (often called slaters in Australia) are small, grey-brown crustaceans with segmented oval bodies that roll into a ball when disturbed. They are not insects and they do not bite, sting or damage the house. They live in damp soil, under stones, pots, timber and mulch, and after a stretch of wet weather they can appear in surprising numbers around the outside walls and inside the home. With showers forecast through Saturday and temperatures climbing from 23 to 25 degrees early next week, this is the time of year Sydney households see them most.
First, identify them calmly
A slater looks a little like a tiny armadillo: grey to brown, around 1 cm long, with seven pairs of legs and a rounded back. When disturbed it curls into a tight ball. Woodlice are often confused with millipedes and centipedes, which are longer and more mobile. They can also be mistaken for small beetles. If you are not sure what you are seeing, take a clear photo before you move anything - a photo, date and location give a technician far more to work with than a description.
Grey-brown, oval, around 1 cm, curling into a ball when touched.
Found in damp places: under pots, stones, timber, mulch and along subfloor edges.
Often active at night or early morning after rain.
Harmless to people, pets and the structure of the home.
Why a wet week pushes them indoors
Woodlice breathe through gill-like structures and need constant moisture, which is why wet weather suits them. When the soil around a house stays saturated, the ground under slabs, garden beds and subfloor access points becomes their ideal habitat. When conditions flood or dry out, they move. A long showery week like this one leaves garden beds sodden and then slowly warms, so slaters search out drier shelter in wall cavities, under door thresholds and inside garages, bathrooms and laundries. You are most likely to notice them near the ground floor, around external doors and where paving meets the house.
Slaters are not a sign of a dirty house and they are not a health risk. Treat them as a moisture signal: the useful work is finding where water is pooling or staying damp, not spraying the creatures themselves.
Where to look after the rain
Along door thresholds, especially external doors at ground level and garage doors.
Bathrooms, laundries and any room with a water source or damp floor.
Under pots, stones, timber stacks, mulch and compost bins against the house.
Subfloor access points, weep holes and gaps where paving or garden beds meet the wall.
Check these places in the early morning or after dark, when the activity is highest. Simply lifting pot saucers and sweeping debris away from the wall line will often show you where they are coming from.
Reduce the damp and the hiding places
The most effective steps are about water, not chemicals. Fix leaking taps and downpipes, clear blocked gutters and drains, and rake back mulch or garden beds so the soil does not sit against the wall. Lift pot saucers that hold water, move timber and compost away from the house, and improve airflow in subfloor and laundry areas. Indoors, wipe up condensation and use exhaust fans in bathrooms and laundries.
Rake mulch and soil back so they do not touch the wall line.
Clear gutters, downpipes and drains so water moves away from the house.
Remove or raise timber, compost and pot saucers near the building.
Ventilate subfloor, laundry and bathroom areas on drier days.
If you choose a commercially labelled product, use it only for its intended setting and follow the current label exactly. The APVMA explains correct chemical use. For moisture pests, drainage and shelter work should come first - products are rarely a substitute for fixing where the water sits.
When to get help
In most cases slaters settle down once the ground dries and the shelter work is done. Call a licensed technician if you are seeing very large numbers inside the home for weeks, if the activity is concentrated in a wall cavity or subfloor you cannot address, or if you want a technician to check whether the moisture is coming from a building defect such as a leak, poor drainage or rising damp. A technician who knows Sydney homes will treat the source and the entry points together, rather than just the insects you can see.
WOODLICE OR SLATERS AROUND THIS WEEK?
Text your suburb, property type and where you are seeing them.
Tell us whether they are near doors, in the laundry or under the house, and we can confirm what is worth doing.