When should I call an exterminator for mice?

Call an exterminator when the problem is bigger than a few mice in one spot, when it involves rats, or when mice have reached wiring or the roofline. A mouse or two in the kitchen is usually a job for a line of snap traps and an afternoon of sealing gaps. The signs below tell you when it has gone past that.

When you can usually handle it yourself

For a small problem, trapping is the preferred method in homes, garages and other buildings where only a few house mice are present.^[12] Mice are curious and explore new objects, so traps often work quickly on them.^[5] Mice usually stay within 30 feet of their nests,^[9] so a cluster of droppings under one sink usually means a nest nearby, not a house full of mice.

Give it a fair test: set traps every night and seal the obvious gaps. A mouse can squeeze through any opening ¼ inch across,^[5] so check under doors, around pipes under sinks and where cables enter. How to get rid of mice in your house covers trap placement, bait and safe cleanup. If catches fall off and the droppings stop, you are done.

Stop and call a pro if

Traps keep catching mice. If the catch does not taper off, the population is larger than it looked. A large infestation may take a combination of methods, including traps or rodenticides,^[9] and rats and mice have very short generation times and can populate a building in a short amount of time.^[5]

You see mice in daylight. Rats and mice usually search for food at night. Seeing one during the day can mean food is scarce or the population is high.^[5]

The droppings or holes are rat-size. A house mouse weighs about half an ounce and leaves rod-shaped, pointed droppings; a Norway rat weighs 3 to 21 ounces and leaves capsule-shaped droppings.^[5] Rats are hard to control because they avoid new objects, including traps and baits, and they may travel hundreds of feet a day for food or water.^[10] Norway rats generally nest at or below ground level, and roof rats prefer elevated places,^[5] so burrows along the foundation or noise high in the walls both deserve a professional look.

Wiring is chewed. Mice chewing on wire insulation can cause electrical shorts and fires.^[5] Call a professional if electrical equipment has rodents in it or looks damaged.^[11] Have an electrician check chewed wiring once the rodents are dealt with.

The way in is high up. Rats and mice also enter through the eaves, the roof and attic vents, not only the first three feet above the ground.^[5] Sealing at the roofline means ladder and roof work, which is not a homeowner job.

You are thinking about poison. Consumer rodent poisons are sold only as ready-to-use bait stations with block or paste bait, and second-generation anticoagulants are registered only for commercial and structural pest control.^[8] Poison has a cost inside a house: rodents baited indoors often die in hidden, hard-to-reach places, leaving a decaying, smelly body that attracts flies.^[5] A company can decide where baiting makes sense and where trapping is better.

You have tried and it keeps coming back. National Pesticide Information Center specialists put it plainly: "Consider hiring a professional. There’s an art to managing mice."^[9]

What a pest control company should do

A good company starts with an inspection, not a spray. The EPA's advice is that any company should inspect your home and outline a recommended control program, including the pests to be controlled, the extent of the problem, the active ingredients, non-chemical alternatives, how to reduce your exposure, and steps to minimize the problem in the future.^[7] For rodents, expect the plan to cover where they are getting in and how those openings will be sealed, not only traps or bait.

Virginia Tech's integrated pest management plan for rats and mice has four parts: prevention, monitoring, the least toxic control methods, and record keeping.^[5] A company working that way will look for nesting areas, food, water and entry points, set traps or bait stations, and come back to check them.

If bait is used, it should be in locked stations. Under EPA rules, professional bait products are not packaged in bait stations, but their labels require tamper-resistant stations wherever children under six, pets or nontarget wildlife have access, and for all outdoor above-ground placements.^[8] Products made for professional applicators are not to be sold in consumer stores such as hardware and grocery stores.^[8]

How to hire one in Virginia

• Licence. Under Virginia law, no one may apply or recommend a pesticide commercially without a pesticide business license and a certified commercial applicator on staff.^[1] The Virginia Department of Agriculture and Consumer Services adds that a separate license is required for each business location, and every license expires on March 31 each year.^[2]
• Insurance. To be licensed, a business must show a certificate of insurance for at least $100,000 for property damage, $100,000 for personal injury to or death of one person, and $300,000 per occurrence.^[2]
• Ask. The EPA says to ask to see the company's license, and if you have concerns, call your state pesticide regulatory agency.^[6] It also suggests you get bids from two or three companies, look at value more than price, and ask neighbors and friends whether they were satisfied with the company.^[7]
• Follow-up. Ask how many visits are included and what happens if mice return, and be skeptical of a company that will not stand behind its work.^[7] Hiring a company does not end your part of the job: you still need to evaluate the results and keep asking questions until the pests are under control.^[7]

If it is not mice

Heavy thumps, daytime noise in the attic or chewed holes far larger than a mouse needs point to squirrels or raccoons, which are wildlife jobs rather than pest control. Licensed trappers can capture certain game and furbearer species during open seasons but cannot move live animals off your property, while Commercial Nuisance Animal Permit holders can trap most wildlife species at any time of year and take them offsite for humane dispatch.^[4] The Virginia Department of Wildlife Resources' Trapper Finder Tool lists both near a location you enter, with the species each will trap, and it is up to you to check their references.^[4] Start with what animal is living in your attic.

If you rent

Virginia tenants must keep their unit free from insects and pests and promptly tell the landlord about them, and a tenant can be charged the added cost of treatment caused by an unreasonable delay in reporting.^[3] Report mice in writing before you hire anyone.

Getting help on Loclis

Read what it costs to get rid of mice in Virginia and whether pest control companies need a licence in Virginia. Browse rodent control services, find pest control around Blacksburg or see more pest control answers. When you are ready, describe the job on Loclis so local pest control businesses can quote it or offer an inspection visit first.