How to Get Rid of Rats and Mice: A Complete Guide

Rats and mice are one of the few pests where most people know they have a problem before they ever see the animal. You hear scratching in the ceiling at night, find droppings behind the fridge, or notice a bag of rice with a neat hole chewed in the corner. The good news is that rodents are very predictable. Once you understand where they travel and what they want, getting rid of them is mostly a matter of doing a few things properly, in the right order.

Rat or Mouse? Why It Matters

The treatment is similar, but the details change depending on what you're dealing with.

Feature	Mouse	Rat
Adult body length (without tail)	About 7–10cm	About 16–25cm
Droppings	Rice-grain sized, pointed ends	Larger, capsule-shaped, up to around 2cm
Behaviour	Curious, explores new objects	Cautious, avoids new objects for days
Where they nest	Inside walls, cabinets, stored boxes	Ceilings, drains, burrows, under floors
Entry gap	A hole the width of a pencil	A hole about the size of a coin

That last difference in behaviour is the one that trips people up. Mice will often walk into a new trap the first night. Rats are "neophobic": they avoid anything unfamiliar in their path, so a trap placed yesterday may sit untouched for a week, and people wrongly conclude that trapping doesn't work.

The Signs You Have Rodents

• Droppings along walls, inside cabinets, behind appliances, and in the ceiling space
• Gnaw marks on food packaging, wooden edges, plastic pipes, and electrical cables
• Scratching or scurrying sounds at night, especially in the ceiling or behind walls
• Grease marks — dark smudges along skirting boards and around holes, left by their fur on routes they use every day
• A stale, musky smell in enclosed spaces with heavy activity
• Shredded paper, fabric, or insulation gathered into a nest

Fresh droppings are soft and dark; old ones are dry and crumble easily. Checking which ones you're finding tells you whether the activity is current.

Why Poison Baits Often Backfire Indoors

Rodenticide is the first thing most people reach for, and it's often the wrong choice inside a home:

1. The rodent dies where you can't reach it. A poisoned rat usually retreats into a wall void, ceiling, or under the floor. The smell of a decaying rat in a ceiling can last one to two weeks and is very hard to remove.
2. Risk to children and pets. Loose bait pellets get dragged around and scattered by rodents. Dogs and cats can also be harmed by eating a poisoned rodent.
3. Bait avoidance. Rats that get sick from a small first taste learn to avoid that bait, leaving a population that no longer takes it.

Baits have their place, mainly in locked, tamper-resistant stations placed outdoors or around a building's perimeter. For inside living spaces, trapping is usually cleaner and more controllable.

The Approach That Actually Works

1. Find the Routes First

Rodents run along edges. They keep contact with walls and use the same paths every night. Look for droppings and grease marks to find where they travel, and place traps on those routes, not in the middle of the room.

2. Trap Properly

• Use snap traps, set perpendicular to the wall with the trigger facing the wall, so a rodent running along the edge crosses it.
• Use more traps than you think you need. For mice, several traps a short distance apart in each active area. For rats, a handful along each main route.
• Pre-bait for rats. Put out unset traps with a small amount of bait for three to five days so rats get used to them, then set them. This single step is what turns a "trapping doesn't work" situation into one that does.
• Good baits include a small smear of peanut butter, a piece of dried fish, or nuts, pressed firmly onto the trigger so it can't be lifted off cleanly.

Glue boards catch rodents but are widely considered inhumane, and a trapped rat can drag a board around. Snap traps are the better tool.

3. Remove What Keeps Them There

Trapping reduces the population; removing food and shelter stops it from rebuilding.

• Store rice, flour, pet food, and snacks in sealed hard containers, not bags
• Don't leave food waste or pet bowls out overnight
• Use bins with tight lids, and empty them daily
• Clear clutter in storerooms, especially stacked cardboard

4. Seal the Entry Points (the Step Most People Skip)

If you trap every rodent inside but leave the entry holes open, new ones will move in within weeks. Check:

• Gaps around pipes and cables where they pass through walls
• The gap under doors, especially back and kitchen doors
• Air conditioner piping holes
• Roof eaves, vents, and gaps in ceiling boards
• Floor drains without covers

Seal small holes with steel wool packed in firmly and covered with sealant, or with wire mesh and cement for larger gaps. Rodents chew through foam, plastic, and silicone alone.

5. Clean Up Safely

Rodent urine and droppings can carry disease, including leptospirosis. Don't sweep or vacuum droppings dry, as this can put particles into the air. Wear gloves, spray the area with a disinfectant and let it soak for several minutes, then wipe up with paper towels and bag everything before throwing it out.

When to Call a Professional

DIY works well for a mouse or two in a kitchen. It becomes much harder when:

• You're seeing rats rather than mice, especially in the ceiling or drains
• Activity continues after two to three weeks of properly set traps
• You can't find or reach the entry points, such as roof or ceiling gaps
• The premises handle food, where a rodent sighting can mean a failed inspection or a shutdown

A professional can inspect the ceiling and roof space, map the routes, set up locked bait stations outside, and handle proofing work that needs ladders and access most homeowners don't have.

Key Takeaways

• Droppings, gnaw marks, grease smudges, and night-time scratching are the main signs, and fresh droppings tell you the activity is current
• Rats avoid new objects, so pre-baiting traps for a few days before setting them is essential
• Indoor poison baits often create a worse problem: a dead rat decaying somewhere you can't reach
• Trapping reduces numbers, but sealing entry points is what stops rodents coming back
• Persistent rat activity, ceiling infestations, and anything in a food premises are the clearest cases for professional help

This guide covers general rodent control and is not a substitute for an on-site inspection. If you are feeling unwell after contact with rodent droppings or urine, seek medical advice.