Why do I have cockroaches in my unit or townhouse?
TL;DR — Quick Answer
Cockroaches are common in units and townhouses because they can move through shared walls, plumbing gaps, roof spaces and building cavities. German cockroaches often spread between connected properties, while larger cockroaches may enter through drains, subfloors and external gaps. Professional treatment may be needed for ongoing infestations.
Why are cockroaches harder to control in units and townhouses?
High‑density living means shared walls, roof voids, subfloors, and plumbing. Pests move easily between spaces, so treating only your unit rarely fixes the root problem.
According to the Australian Environmental Pest Managers Association (AEPMA), over 65% of multi‑unit cockroach infestations return within 3 months if treated in isolation.
Pest Control Challenges in Sydney High-Rise Apartments | Solutions
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What’s the difference between large cockroaches and German cockroaches?
Two main groups cause most problems in Sydney apartments. Knowing which you have decides how to treat them.
Large cockroach species
Includes Australian, American, and Oriental varieties. They favour roof voids, subfloors, and wall cavities rather than inside cupboards.
They travel long distances through shared spaces. A single building can have thousands, so one unit spray won’t clear them.
German cockroaches
Smaller, light brown, and found mostly in kitchens, bathrooms, and laundries near water sources. They rarely live in roof spaces.
A female German cockroach can produce up to 400 nymphs in her lifetime. Fun fact: they can survive 10 days without a head, but only about one week without water.
| Feature | 
Large Cockroaches |
German Cockroaches |
|---|---|---|
| Size | 30–45mm | 10–15mm |
| Where they live | Roofs, subfloors, walls | Kitchens, bathrooms, laundries |
| Water needs | Moderate | High—needs constant access |
| Spread risk | Building‑wide | Fast within one unit |
| Best approach | Building/strata coordination | Targeted indoor baiting |
How do I get rid of German cockroaches in my unit fast?
Act as soon as you see them—delays can turn a small issue into a full infestation in 4–6 weeks.
- Fix dripping taps and dry sinks every night—remove their water source.
- Store all food in sealed containers and wipe up crumbs immediately.
- Use professional gel bait + non‑repellent insecticide, not just surface sprays.
Non‑repellent products let cockroaches carry the treatment back to hidden nests, rather than just scattering them into other rooms.
Independent NSW pest surveys show 82% of German cockroach jobs succeed first time when gel bait is used instead of powder only.
For reliable, proven treatment, call us now on 1800 819 189.
What treatments work best for large cockroaches in townhouses?
Large species need products that reach roof voids, subfloors, and wall cavities where sprays can’t reach.
- We use low‑toxicity dusts and odourless liquids that flush cockroaches safely.
- Treatments target breeding sites rather than just visible insects.
- Complies with NSW Health and Australian Pesticides and Veterinary Medicines Authority (APVMA) safety standards.
Many Sydney strata properties now require these methods to meet building hygiene policies.
Why do I see more cockroaches right after treatment?
It is very common to see higher activity for 1–3 days after service. This is actually a good sign.
The products flush cockroaches out of deep hiding spots before they die. You should see numbers drop sharply after day 3.
If activity stays high after 7 days, let your technician know—extra targeted work may be needed.
When should I ask my strata or property manager for help?
If you have large cockroaches coming from shared roof spaces or walls, your unit alone cannot solve the problem.
Ask strata to arrange a coordinated service across all affected units. A 2024 AEPMA study found building‑wide jobs last 3 times longer than isolated treatments.
Read more about multi‑unit pest management rules from NSW Health.
How do I pick a good pest controller for my unit?
Not all services suit apartments—look for these clear signs:
- Uses gel bait + non‑repellent for German cockroaches, not just powder or spray.
- Offers at least 6‑12 month warranties, not only 3 months.
- Understands strata rules and can coordinate with your building manager.
Our local Sydney team often sees clients who paid twice elsewhere for basic sprays that did not work.
Frequently Asked Questions
Can I treat cockroaches in my unit without telling strata?
For German cockroaches you can start on your own. For large cockroaches coming from shared roofs or walls, tell strata—otherwise the infestation will return quickly.
How long until cockroaches disappear completely?
German cockroaches usually vanish in 7–14 days. Large species take 2–4 weeks as the product spreads through hidden areas.
Are the treatments safe for kids and pets?
We use low‑mammalian‑toxicity products approved by the APVMA. Keep children and pets away while drying—after 2–4 hours it is safe to return.
Will cleaning alone get rid of cockroaches?
Good cleaning helps stop new ones arriving, but it will not remove an established infestation. You need professional treatment plus good hygiene.
Do I need my neighbours to get treated too?
For large cockroaches, yes—coordinated treatment across the building is the only reliable fix. For German cockroaches, your unit can be done first.
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Cockroaches in Sydney units and townhouses are often caused by the challenges of high-density living. Shared walls, plumbing systems, roof spaces and neighbouring properties can allow cockroaches to spread between residences. Effective control requires identifying the cockroach species, treating harbourage areas and addressing possible entry points throughout the building.
Need Help With Cockroaches In Your Unit?
Cockroach problems are common in Sydney’s high-density suburbs where apartment buildings and townhouse developments create shared environments. Areas such as Parramatta, Zetland, Mascot, Chatswood and Sydney CBD often experience increased cockroach pressure due to connected plumbing, neighbouring units and shared building spaces.
We service all Sydney suburbs including the Eastern Suburbs, North Shore, Western Sydney, and Inner West.