Signs of Rodent Infestation in Ottawa Homes
How to identify mice and rat activity in your home, understand the health risks, and know when to call a professional.
By PrecisionPro Pest Solutions · Updated April 2026 · 7 min read
Rodent infestations are one of the most common pest problems in Ottawa, particularly during the colder months when mice and rats seek warmth indoors. Early detection is critical — a single pair of mice can produce up to 60 offspring per year, turning a small problem into a full-blown infestation quickly.
8 Warning Signs to Watch For
Droppings
Mouse droppings are small (3-6mm), dark, and pellet-shaped. Rat droppings are larger (12-18mm) and blunt-ended. Fresh droppings are dark and moist; old ones are dry and gray. Check near food sources, along baseboards, and in cupboards.
Gnaw Marks
Rodents gnaw constantly to keep their teeth trimmed. Look for marks on food packaging, wood, electrical wires, plastic containers, and even drywall. Fresh gnaw marks are light-colored; older ones darken over time.
Scratching & Scurrying Sounds
Rodents are most active at night. Listen for scratching in walls, ceilings, or under floors. Mice make higher-pitched, lighter sounds; rats make heavier, more deliberate noises.
Nesting Materials
Rodents build nests from shredded paper, fabric, insulation, dried plant material, and other soft materials. Nests are usually found in hidden, undisturbed areas like wall voids, attics, and behind appliances.
Grease & Rub Marks
Rodents follow the same paths repeatedly, leaving greasy, dark marks along baseboards, walls, and around entry points. These rub marks are caused by oil and dirt in their fur.
Tracks & Footprints
In dusty areas, you may see small footprints or tail drag marks. You can test by sprinkling a thin layer of flour or talcum powder along suspected pathways and checking for prints the next morning.
Unusual Pet Behavior
Dogs and cats may become fixated on certain areas — pawing at walls, staring at cabinets, or showing unusual alertness. Pets can hear and smell rodents long before you notice other signs.
Urine Odor
A strong, musky ammonia-like smell can indicate a significant rodent presence. This is especially noticeable in enclosed spaces like cabinets, attics, and crawl spaces.
Health Risks of Rodent Infestations
Rodents are not just a nuisance — they pose serious health risks to your family:
Hantavirus
Spread through contact with rodent droppings, urine, or nesting materials. Can cause Hantavirus Pulmonary Syndrome (HPS), a severe respiratory disease.
Salmonella
Contamination of food and surfaces through rodent feces. Causes food poisoning with symptoms including diarrhea, fever, and abdominal cramps.
Leptospirosis
Bacterial infection spread through rodent urine, often contaminating water sources. Can cause liver and kidney damage in severe cases.
Allergies & Asthma
Rodent dander, droppings, and urine can trigger allergic reactions and worsen asthma symptoms, particularly in children.
What to Do If You Find Signs
1. Don't panic. Rodent infestations are common and treatable.
2. Document what you find. Take photos of droppings, gnaw marks, or other evidence. Note locations and approximate quantities.
3. Avoid disturbing nesting areas. Hantavirus can become airborne when nesting materials are disturbed. Do not sweep or vacuum droppings without proper protection.
4. Contact a professional. A certified pest control technician can assess the severity and implement the most effective treatment plan. Learn about our rodent control services.
5. Don't rely solely on DIY methods. Store-bought traps and poison can be partially effective but rarely address the root cause or prevent re-entry.
Suspect a Rodent Problem?
Don't wait for it to get worse. Contact us for a free inspection and same-day emergency service.