It's late, the house is quiet, and you hear it: a faint scratching inside the wall behind the bed. Most people's first thought is "Do I have mice?" Once you've noticed the common signs of mice in walls, that question is usually settled. The question that matters for your wallet is different: is this one mouse, or a breeding population with a way in?
One mouse is a $5 snap trap and a tube of caulk. A population that keeps getting in through gaps you can't find is a job for a pro. This checklist walks through each sign, what it tells you, and where the line sits between setting a trap and booking an inspection. It also covers what exterminators charge and what a fair first visit looks like.
When is it safe to handle mice yourself?
Short answer: when the signs are limited to one spot, they don't come back after a careful cleanup, and you can find and plug the gap. DIY makes sense when all three of these are true:
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You've found a few droppings in one area, such as under the kitchen sink or in one corner of the pantry.
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After you clean the area the way the CDC recommends (see the cleanup box below), no new droppings show up.
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You can see an obvious gap, like an opening around a pipe, and plug it.
Supplies are cheap. This Old House, citing prices from Lowe's and Home Depot, puts snap traps at $3 to $6, glue traps at $5 to $15, bait stations at $8 to $20, live traps at $10 to $30 and electronic traps at $20 to $50. A couple of snap traps along the wall where you found droppings is a reasonable first move.
If any of those three conditions doesn't hold, keep reading.
Checklist item 1: What do mouse droppings look like, and what do they tell you?
According to the CDC, "Rodent droppings are pointed at one end and often contain hair." NC State Extension describes mouse droppings as about 1/4 to 1/2 inch long with tapered ends.
Here's what most people get wrong: a big pile of droppings doesn't necessarily mean a big pile of mice. NC State Extension notes that "Mice can produce between 50 and 75 individual droppings per day." One mouse can make a shelf look like a crime scene within a week.
What matters more than how many droppings you find is whether they keep showing up. The CDC's test is simple: "One way to be sure is to safely clean the area. If droppings are present after cleaning, this indicates an active rodent presence." Clean it well, check again in a few days, and let the result guide your next step.
Checklist item 2: What does scratching in the walls mean?
NC State Extension lists "scratching and clawing noises within wall voids" as a sign of mice. The National Pest Management Association (NPMA), the pest control industry's trade group, advises homeowners to listen for "strange noises, especially in quiet areas like attics and basements."
Where you hear the noise matters more than how loud it is. UC IPM (University of California Agriculture and Natural Resources) says house mice seldom travel more than about 30 feet from their nest and food. So:
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Scratching in one wall, one room: could be a single mouse. Trap and watch.
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Scratching in walls on opposite ends of the house, or on more than one floor: usually more than one mouse, and likely more than one nest.
Checklist item 3: Gnaw marks, nests and odor
Gnaw marks. The CDC says rodents' "teeth leave distinct marks and are a good sign that rodents were active in the area." The key word is were. Old gnaw marks on a basement beam could date back years. UC IPM says to look for "droppings, fresh gnaw marks, and tracks, which indicate areas where mice are active." Fresh, light-colored chewing is the kind that counts.
Chewed wiring. NC State Extension lists chewed packaging, foam and wires among the signs. Packaging is a nuisance. Wiring is a reason to call someone, both a pest pro and possibly an electrician to check the damage.
Nests. UC IPM says mouse nests are made of "finely shredded paper or other fibrous material." NC State also notes nests built from collected material. Finding a nest in a drawer or a stored box is common. Finding one packed into attic or wall insulation means mice have settled in.
Odor. NC State Extension describes "a musty smell associated with mouse urine." UC IPM says the musky odor is most noticeable in large or long-term infestations. If you can smell it, you're probably past the one-mouse stage.
Checklist item 4: How small a hole can a mouse fit through?
About 1/4 inch, roughly the width of a pencil. The CDC says, "Mice can fit through a hole the width of a pencil (1/4 inch or 6 millimeters in diameter)." NC State Extension and UC IPM agree. UC IPM adds that house mice "can squeeze under gaps ¼ inch tall, and through openings 3/8 inch wide."
The CDC suggests checking these spots:
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Inside: under and behind kitchen cabinets, around pipes under sinks and appliances, windows and doors, closets, the basement, the attic and floor drains.
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Outside: roof edges and eaves, windows and doors (especially ones without weather stripping), where the foundation meets the ground, vents, and openings where utility lines come in.
For small holes, the CDC says, "Fill small holes with steel wool," then cover it with caulk or spray foam to hold it in place. For larger holes, it lists lath screen or metal, cement, hardware cloth or metal sheeting. NC State Extension recommends lath metal, copper mesh or steel wool covered with caulk, and warns against relying on expanding foam because mice may chew through it. UC IPM says steel wool is a good temporary plug but may rust, and that plastic screening, rubber, vinyl, foam and wood don't work for plugging holes. NC State also recommends rodent-proof door sweeps and metal kick plates, with no more than 1/4 inch of clearance under exterior doors.
The DIY limit: if you can't find the gaps, or they're at the roofline, in the eaves or around utility penetrations you can't safely reach, that's the point to bring in a pro.
Why a small mouse problem gets bigger
The numbers explain why waiting rarely works. UC IPM says a female house mouse may have 5 to 10 litters a year of about 5 or 6 pups each, and that under stable conditions mice "can reproduce year-round." A warm house with food is exactly that kind of stable condition.
Trapping removes the mice that are already inside. Sealing keeps new ones out. UC IPM puts it plainly: "Exclusion is the most successful and permanent form of house mouse control." That sealing work, more than the traps, is what you're paying a pro for.
Poison bait is another dividing line. NC State Extension says, "Rodenticides are best handled by pest management professionals."
Timing matters too. It's November, and the NPMA estimates that "Each winter, rodents invade an estimated 21 million homes." Keep in mind that the NPMA is the industry's trade group. Its advice: "If you suspect a rodent infestation, it is best to contact a pest control professional."
Signs it's time to call a pro
Call for an inspection if any of these apply:
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Droppings come back after you've cleaned the area properly.
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You see signs in several rooms or on more than one floor.
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You hear scratching in more than one wall.
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You find chewed wiring.
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You find nests in insulation.
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You notice a persistent musty odor.
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You can't find the entry points, or they're too high or awkward to reach.
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You're thinking about using poison bait.
How much does a mouse exterminator cost?
Most homeowners pay $150 to $550, with an average of about $350, according to This Old House (updated April 2026). Fixr (updated January 2025) puts the national average a bit higher at $525. Its range for a package that includes inspection, sealant, traps and a follow-up visit is $450 to $600, with a low end of $250 and a high end of $2,000.
Typical price breakdown
| Item | Typical cost | Source |
|---|---|---|
| Standalone inspection | $75 to $100 | Fixr |
| Initial visit including inspection | $350 to $550 | Fixr |
| Per-visit charge (some exterminators) | $75 to $125 | This Old House |
| Emergency or after-hours add-on | $100 to $200 | This Old House |
| Separate exclusion service | $50 to $300 | Fixr |
| Handyman for sealing (up to 3 hours) | $100 to $300 | Fixr |
| Dead mouse removal (if not covered by contract) | $100 to $200 | Fixr |
| House deep clean | About $325 average | Fixr |
| Whole-home fumigation | $2,000 and up (Fixr: $2,000 to $6,000) | This Old House, Fixr |
Cost by method
For a 2,000-square-foot home, Fixr lists traps at $250 to $650, bait stations at $450 to $650 and rodenticides at $750 to $1,000.
Service contracts
Fixr's contract ranges: yearly $200 to $450, quarterly $450 to $900, and monthly $800 to $1,200. Find out whether a contract is optional before you sign anything.
A real local price: Phoenix
Most companies don't publish prices, but one Phoenix company does. Busy Bee Pest Solutions lists mouse control at $245 for the first visit and $95 per follow-up, after a free inspection. The first visit includes a "Free 61-point inspection, snap traps indoors, locked stations outside." Full exclusion of every entry point is a separate package, priced after the inspection. That split is common, so read every quote carefully to see whether sealing is included.
Location matters. This Old House notes that rural homes may cost more because of the technician's travel time, and urban homes may cost more because of demand and cost of living.
What should a fair first visit include?
Using guidance from the National Pesticide Information Center (NPIC, Oregon State University), here's what to expect:
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An inspection before any treatment. Anyone who sets bait before looking for entry points is selling a product, not a fix.
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A written estimate. NPIC suggests asking, "Can the company offer an estimate for services in writing?"
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A properly licensed technician. NPIC: "Do technicians have current licenses? Is the license the correct classification for the job?" You can confirm a license with your state pesticide regulatory office.
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A follow-up schedule. Fixr notes that extermination needs at least one follow-up visit "within 90 days." The quote should say how many follow-ups are included.
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Guarantee terms. NPIC: "Is the company able to provide a guarantee for their work? What are the terms?"
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Long-term costs. If a contract is required, NPIC says to ask, "what are the long-term costs?"
Red flags and how to compare two quotes
NPIC recommends getting estimates from more than one company. When you put two bids side by side, check these points:
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Exclusion or traps only? A cheaper bid that skips sealing will probably cost more over time, because new mice will keep getting in.
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How many follow-ups? One visit and done doesn't match the 90-day follow-up norm.
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Contract term. Is a monthly or quarterly plan required, and what does it cost over a full year?
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Bait without an inspection. That's a red flag.
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Nothing in writing. That's a red flag too. Don't let work start until you have a written quote.
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License questions dodged. If they can't tell you their license number and classification, keep looking.
Cleanup safety: the CDC method
Whether you hire someone or not, you'll probably clean up droppings yourself. The CDC's cleanup steps:
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Open all doors and windows and let the area air out for 30 minutes before you start.
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Put on rubber or plastic gloves.
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"Don't vacuum or sweep rodent urine, droppings, or nesting materials."
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Mix "1.5 cups of household bleach in 1 gallon of water (or 1 part bleach to 9 parts water)."
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Spray it on and let it soak for 5 minutes, or as long as the product label says, before wiping it up.
This is also the first half of the CDC's active-infestation test. Clean it this way, then check back.
The bottom line: trap or call?
If the signs are limited to one spot, set a couple of snap traps, clean the area the CDC way and check again in a few days. If no new droppings appear and you've sealed the gap with steel wool or copper mesh and caulk, you're likely done.
If droppings come back, you're hearing scratching in more than one place, or you can't find the way in, book an inspection. Ask for a written quote that includes exclusion, spells out the follow-up visits and lists any contract costs, and get at least two bids. A national average of roughly $350 to $525 is a reasonable range to keep in mind when the numbers come in.
Related reading
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What Separates a Budget Garage Door Opener From a Premium One
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How to Keep Stink Bugs Out This Fall by Sealing the Gaps First
Sources
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NC State Extension: Surveillance and Management of Common Structure-Invading Mice (Dec. 12, 2024)
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NPMA: Fall Is in Full Force and So Are Rodents (Oct. 21, 2024)
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This Old House: Mice Exterminator Cost (updated Apr. 3, 2026)
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NPIC (Oregon State University): Choosing a Pest Control Company
Note: This article contains AI-assisted content and has been reviewed by our editorial team.
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