House mouse: spotting it and cutting off its routes
A gap of a few millimetres is all it needs to move from room to room.
Guide 02
Mus musculus
Key points
The house mouse (Mus musculus) is 7 to 10 cm long without its tail and fits through a gap of about 6 mm. It settles indoors close to food, soils what it touches and multiplies quickly. Effective control combines closely spaced stations on its routes with sealing the gaps around pipes and ducts.
Mice are true building dwellers: behind kitchen units, inside wall linings, under skirting boards, in cable ducts. They drink very little, as their food supplies most of the water they need.
Curious by nature, a mouse readily explores anything new, but it lives within a few metres of its nest. Stations therefore need to be numerous, close together and placed exactly on its runs.
Spotting signs of house mice
- 1Small black droppings, 3–6 mm, like grains of rice, in cupboards and behind appliances.
- 2A sharp smell of urine in poorly ventilated rooms.
- 3Pierced packaging, shredded paper or insulation used for a nest.
- 4Faint scratching at night in partitions or the ceiling.
Nuisance level
An indicative guide from our technicians, from 1 (moderate) to 5 (high).
- Health
- 3/5
- Damage
- 4/5
- Breeding
- 4/5
Why act
- Food, worktops and dishes soiled by urine and droppings.
- Urine carries allergens that can aggravate asthma.
- Cables and insulation gnawed in ducts and wall linings.
- Rapid breeding: around three weeks' gestation and many litters a year.
Our treatment, in four stages
- 01
Locate
Locate: search for droppings and urine traces, with a UV torch if needed, and for gaps around pipes, ducts and skirting boards.
- 02
Treat
Treat: rodent control with tamper-resistant bait stations spaced closely along the runs, or mechanical traps in food areas.
- 03
Check
Check: follow-up visit built into the protocol, stations inspected, set-up moved to wherever activity continues.
- 04
Prevent
Prevent: gaps around pipes and ducts sealed, door sweeps, vent grilles, photo report and advice on active vigilance.
Good everyday habits
What you can do to lower the risk of a new infestation.
- Keep cereals, flour and pet food in sealed containers.
- Empty the pet bowl in the evening.
- Check the pipe gaps under the sink and behind appliances.
- Fit door sweeps on cellar and outside doors.
Your questions
I've only seen one mouse: should I act?
Yes, because a mouse seen in daylight usually means others are nearby. Acting early makes the treatment shorter and simpler.
Do ultrasonic devices work?
Any effect they have does not last: mice get used to them. Cutting off food and sealing gaps works far better.
Why do mice turn up mainly in autumn?
As it gets colder, they look for warm shelter with food. Homes and shops with unsealed gaps are the first places they try.
House mice in your home or your business?
Flat, house, restaurant, shop or office: price including VAT shown before you book, 2-hour window, same-day photo report and advice to lower the risk of a return.