Why Rats Keep Coming Back: Understanding Access to Your Home

Rodents reproduce quickly and rarely exist in isolation. Removing one rat — or even several — from an area does not address the population in the surrounding environment. New rodents move in to fill the territory, and the cycle resumes.

This is fundamentally different from possum control, where a single possum can be excluded and the entry point sealed. With rodents, the issue is often the ongoing pressure from the surrounding environment — rats approaching the building from outside, finding access and establishing themselves indoors.

When assessing how rodents are accessing a building, the principle is different from possums. Rodents — and mice in particular — can use very small structural openings. Unlike possums, where access is assessed within an approximately three metre climbing range, rodents can exploit gaps that are far smaller and closer to ground level.

The approximately 300mm access principle reflects this: when assessing vegetation, structures and surrounding access routes, features within approximately 300mm of a potential gap can provide the access a rodent needs. Rodents can squeeze through surprisingly small openings.

Because rodents approach buildings from the surrounding environment, perimeter bait stations are generally preferred for long-term control. Perimeter stations address rodents before they enter the building, intercepting them at the boundary where they are most active.

Roof baiting may be appropriate in specific situations — where roof-space activity is confirmed and access from the roof is a factor — but it should not automatically replace perimeter management. The treatment design depends on what the inspection finds.

• Perimeter bait stations are generally positioned approximately 6 to 8 metres apart where practical.
• Where roof baiting is appropriate, bait may be positioned approximately every 2 metres along the relevant roof line.
• These are operational guidelines, not guarantees — actual placement depends on the property and the inspection findings.

One of the most common misconceptions about rodent control is that bait stations should start working immediately. In practice, new bait stations may take approximately 10 days to one month before rodents begin feeding from them.

Rats in particular are cautious of new objects in their environment — a behaviour known as neophobia. A new bait station placed in their territory may be approached, investigated and ignored for days or weeks before it is trusted enough to feed from. This is normal rodent behaviour, not a sign that the treatment has failed.

Installing bait stations is only the beginning. Long-term protection requires ongoing monitoring and replenishment — a managed program, not a one-off treatment.

After the initial installation and the first follow-up (generally around two weeks), there is no universal fixed maintenance interval. Maintenance frequency depends on actual bait consumption and rodent activity:

• If bait is being consumed, stations are replenished and the interval may be adjusted based on consumption rate.
• If no bait is consumed, monitoring continues — the stations are present and intercepting any rodents that begin feeding.
• The program adapts to what is actually happening at the property, rather than following a fixed schedule regardless of activity.

Rodent proofing can improve control, but it is not a universal solution — and this is an important difference from possum exclusion. Because rodents can use numerous very small openings, complete rodent exclusion may be impractical.

Proofing is recommended where a specific, practical access opportunity can materially improve the treatment outcome — for example, sealing a gap that rodents are clearly using to enter a particular area. In those cases, proofing and perimeter control work together: the bait stations manage the population, and the proofing removes a specific access route.

Professional bait stations are designed to minimise risk to children, pets and wildlife. The Possum Man considers these factors when designing rodent treatment — using the minimum amount of poison reasonably necessary for effective control.

No absolute safety claim can be made about bait, pets, children or wildlife. The stations are designed to reduce risk, but responsible placement and the managed nature of the program are what make the approach safer — not a guarantee of zero risk.

A long-term rodent control program is not a single service call. It is:

• Diagnosis — confirming rodents are the cause and assessing access opportunities.
• Treatment design — selecting the right station type and placement for the property.
• Installation — placing perimeter and, where appropriate, roof bait stations.
• Monitoring — checking consumption and activity at follow-up intervals.
• Replenishment — replacing consumed bait and adjusting the program as needed.
• Ongoing maintenance — adapting to the actual activity at the property over time.

This is why rats that 'come back' after a one-off treatment aren't evidence of failure — they're evidence that a one-off treatment isn't a control program. A managed system is what provides long-term protection.