How to Keep Cockroaches Out of Your Home

Something just scuttled past your feet in the dark. What was that? You turn the light on, and then you see it: a cockroach.

Before you panic, remember that it’s an easily rectifiable problem. Whether you’ve already spotted a cockroach or want to stop them from ever infiltrating your home, our guide will walk you through practical prevention strategies on how to keep cockroaches out of your home.

Afraid it might be too late? We also cover the situations where professional pest control intervention becomes necessary. Keep reading to find out more!

Know Your Enemy: Common Cockroaches in Your Area

Not all cockroaches are created equal. Here are the three you’re most likely to encounter around your home.

Gisborne Cockroach

Ranging in size from 20-45mm, the Gisborne cockroach is dark and shiny with pale edges around its body, and has no wings. As New Zealand’s most common cockroach species, this primarily outdoor-dwelling insect can typically be found in gardens where they feed on decaying wood and organic matter.

While Gisborne cockroaches can wander into your home, they don’t establish indoor populations. If you spot one inside, it’s most likely lost and looking for a way back out.

That said, regular sightings indoors could indicate an outdoor population too close to your home, and that’s when you should contact a specialist cockroach exterminator to assess the situation and create a barrier treatment plan.

Native Wood Cockroach

Similar to their Gisborne cousins in behaviour and habitat, these beneficial black, brown, or yellow-coloured insects create tunnels in soil, feed on decomposing wood, pollen, and leaves, and generally keep to themselves outdoors.

They’re part of a healthy garden ecosystem, but can become problematic if their populations grow too large near your home. Understanding how to prevent cockroaches from entering your home starts with managing these outdoor populations.

German Cockroach

Small, prolific, and exclusively indoor-dwelling, these are the cockroaches that create real infestations and should be a cause for concern. These light to mid-brown insects grow up to 15mm (about half the size of outdoor species) and are drawn to warm, moist environments with access to food—making your kitchen their ideal habitat.

What makes them particularly alarming is their reproduction rate: one female can lay up to 240 eggs in her 200-day lifetime, carrying the egg case with her until just before hatching.

This species is responsible for disease transmission, triggering asthma allergies, food contamination, and unsanitary conditions. And here’s the kicker—their ability to hide in the tiniest crevices, rapid reproduction, and growing resistance to over-the-counter treatments make them extremely difficult for homeowners to eliminate on their own.

Cockroach Prevention Tips

Eliminate Food Sources

Your kitchen is ground zero for cockroach activity. Control the food, and you’re already winning half the battle.

• Store all food, including dry goods like flour, sugar, cereals, and pasta, in sealed containers
• Empty your rubbish bin before bed every night
• Clean benchtops immediately after meals and never leave dirty dishes in the sink overnight
• Wipe down the outside of sauce bottles, jars, and condiments regularly
• Rinse recyclable containers before storing them
• Remove pet food overnight and store in sealed plastic containers during the day
• Replace cardboard storage boxes with plastic bins
• Never store cardboard long-term in your subfloor, garage, or anywhere indoors

Remove Water Sources

While food attracts cockroaches, water is actually more critical to their survival.

Cockroaches can survive for weeks without food but only a few days without water, making moisture control your secret weapon.

• Fix leaky taps immediately
• Check under sinks for any new leaks
• Wipe down all sinks and benchtops to remove water droplets
• Keep toilet lids closed
• Cover drinking glasses overnight or switch to sealed water bottles
• Empty pet water bowls before bed every night

Seal Entry Points

One of the most important steps in how to prevent cockroaches from entering your home is sealing potential entry points. While German cockroaches primarily spread through infested items like boxes, appliances, and second-hand furniture, outdoor cockroach species will take advantage of any gaps or cracks to wander inside.

• Install door seals and snakes on all external doors
• Inspect all window frames and repair any cracks or deterioration
• Check fly screens regularly for tears and ensure they fit tightly in their frames
• Use appropriate filler or sealant to close cracks in walls, gaps in skirting boards, and spaces around window frames
• Cover sub-floor vents, roof vents and bathroom or kitchen exhaust vents with fine mesh
• Seal gaps around pipes and cables where they enter the house
• Use sink plugs when drains aren’t in use and consider placing thick mats over drain holes overnight

Eliminate Hiding Places

Cockroaches are thigmotactic, which means they have a strong preference for tight, confined spaces where surfaces touch their bodies.

Indoors:

• Make a complete transition from cardboard to plastic storage bins throughout your home
• Inspect second-hand furniture, appliances, or even groceries in cardboard boxes for signs of cockroaches before bringing them inside
• Pull out and clean behind your major appliances quarterly
• Keep cupboards organised so you can easily see and access all contents
• Check and clean inside your toaster regularly, inspect coffee machines, and wipe down the inside of your microwave

Outdoors:

• Store firewood at least five metres away from your house, preferably on a raised rack
• Keep compost bins sealed with secure lids and positioned well away from your house
• Maintain a clear space of at least 50cm around your house foundation, using gravel or paving instead of organic mulch
• Reduce leaf litter near your house, especially during autumn
• Keep outdoor storage organised using plastic bins instead of cardboard boxes

Perform Regular Inspections

Prevention requires vigilance, and regular inspections allow you to catch problems early when they’re still manageable.

Weekly checks:

• Under the kitchen sink
• Behind kitchen bins
• Corners of cupboards
• Around the base of appliances
• Behind the toilet base
• Laundry cupboard corners

Monthly deep inspections:

• Pull out major appliances and clean behind/underneath
• Empty one cupboard section at a time, wipe down all surfaces
• Check inside electrical outlet faceplates, door hinges, and drawer runners
• Look behind pictures and mirrors
• Inspect sub-floor and roof void areas seasonally (if accessible)

When to Call the Professionals

Immediate professional intervention is essential if you’re:

• Seeing cockroaches during daytime
• Experiencing multiple sightings despite prevention efforts
• Finding egg cases regularly
• Noticing signs in food preparation areas
• Observing increasing rather than decreasing activity

Spotted any of these? It’s time to contact Combat Pest Control for a professional assessment—we’ll determine the severity of the situation and outline the necessary steps.

What appears to be a minor issue can quickly escalate into a major infestation.

If you are already dealing with an active problem rather than trying to prevent one, our guide on how to get rid of cockroaches in your home covers why they are so hard to shift and which DIY methods actually work.

Ready to Take a No-Roach Approach?

Learning how to keep cockroaches out of your home comes down to consistency and vigilance. A few minutes each evening spent sorting your kitchen, combined with regular inspections and smart storage, is your recipe for a cockroach-free home.

That said, persistent German cockroaches are a different beast altogether. They breed at terrifying rates and hide in spaces you can’t reach, sticking around even through the most intense prevention and DIY treatments.

If you’re seeing cockroaches despite your prevention efforts, finding egg cases, or noticing any of the warning signs we’ve discussed, it’s time to call in the cavalry.

Book a service online with Combat Pest Control and let our team help you achieve peace of mind for your family.