The short version
Rodent control in Spokane, Washington, is mostly about fall. As winter lows head toward an average of 23F, house mice, deer mice and Norway rats move into walls, garages and crawlspaces, then stay all winter. Seal every gap a quarter inch or larger before October, trap what gets in, and clean any droppings with the wet method because Washington deer mice carry hantavirus.
- Fall is entry season; once Spokane nights drop toward 23F, rodents want your walls.
- WDFW says a rat can use a quarter-inch hole and chew it larger.
- Washington sees 1 to 5 hantavirus cases a year, and about 1 in 3 patients have died.
- Rats can have 6 to 10 young per litter and breed at 3 to 4 months.
- Washington does not regulate killing Norway or roof rats, so trapping needs no permit.
This is for Spokane homeowners hearing mice in walls or ceilings once the heat comes on, renters near Gonzaga or elsewhere in the city finding droppings in kitchens and closets, and anyone with a garage, shed or crawlspace that seems to collect mice every winter. It also helps people about to clean out storage that sat closed since fall.
What to look for
Four rodents live in the Spokane area: Norway rats, roof rats, house mice and deer mice. House mice settle into walls, cabinets and garages. Deer mice are native and normally live outdoors, but they move into garages, sheds, crawlspaces and wall voids when it gets cold, and the Washington State Department of Health says infected deer mice live throughout the state. Norway rats burrow along foundations and come in at ground level, and roof rats are mostly tied to Puget Sound attics on the west side of the state. The seasonal pattern is sharp. Summer highs around 84F keep rodents outside, feeding in yards and gardens. As fall arrives and lows head toward an average of 23F, they push indoors, using gaps around pipes, vents, garage doors and the sill. The Washington Department of Fish and Wildlife notes a rat can get through a quarter-inch hole and chew it larger. Once inside, rodents breed through winter.
- 1Scratching or rustling in walls and ceilings shortly after the furnace starts running.
- 2Small droppings on garage shelves, workbenches or along the sill plate.
- 3Tracks in dust or snow about half an inch long near the foundation, a rat sign.
- 4Gnaw marks on wood, plastic or wiring, often with rough edges.
- 5Nests of shredded paper, insulation or fabric in stored boxes or behind appliances.
- 6A musty smell in a closed shed, crawlspace or camper.
Why it’s worth acting soon
- Rats can have 6 to 10 young per litter and breed again within months, according to WDFW.
- Rodents that move in during fall breed all winter inside warm walls.
- Deer mouse droppings build up in garages and crawlspaces, raising hantavirus risk during cleanup.
- Chewed wiring in walls, attics and vehicles is a fire risk and costly to fix.
- Contaminated insulation becomes harder and more expensive to replace the longer it sits.
Treatment options and typical costs
Fall exclusion
Quoted after inspection
Every gap a quarter inch or larger around pipes, vents, garage doors, the sill and crawlspace openings is sealed with steel wool, hardware cloth, sheet metal or mortar. WDFW notes rats chew small holes larger, so materials need to resist gnawing. Doing this in September or early October heads off much of the winter trouble.
- Time
- Usually one day
- Best for
- Every home with past fall or winter activity
Snap trapping
Quoted after inspection
Traps along walls, in garages, attics and crawlspaces remove rodents already inside. WDFW notes Norway and roof rats are not regulated in Washington, so trapping them requires no permit. Follow-up visits reset traps until catches stop.
- Time
- Two to four weeks
- Best for
- Mice or rats inside living space
Wet cleanup for deer mouse areas
Quoted after inspection
Garages, sheds and crawlspaces with droppings are cleaned using the CDC method: ventilate 30 minutes, soak with a bleach solution of 1.5 cups per gallon, wait 5 minutes, then wipe and bag. Since infected deer mice live throughout Washington, this matters even in the city.
- Time
- A few hours to a day
- Best for
- Storage areas and crawlspaces with heavy droppings
Exterior bait stations
Quoted after inspection
Locked stations along the foundation can lower outdoor numbers on properties next to open land or the river corridor. They should be tamper resistant and kept away from pets. Bait supports sealing but does not replace it.
- Time
- Ongoing service
- Best for
- Properties with steady outdoor pressure
Prices are typical published ranges. Ask what’s included before you compare quotes.
Under the sink is the first place to check: the hole where the pipe passes through the cabinet back is often cut much bigger than the pipe.Winter in the walls: how Spokane's cold shapes rodent control.
In summer, with highs near 84F, mice and rats live outdoors in yards, gardens and fields. As fall nights cool, they look for warmth. Gaps around pipes, vents, dryer exhausts, garage doors and the sill plate are their way in. Once inside, they nest in wall voids, attics, crawlspaces and garage storage, and they stay until spring. That makes timing everything. Sealing in September, before the cold arrives, keeps most rodents out. Waiting until December means trapping rodents that already have nests in your walls. Winter also changes how you find them. Scratching in walls after the furnace starts running is a classic sign. Fresh snow near the foundation can show tracks leading to entry points. A Spokane provider can use those clues to find openings and seal them, even mid-winter. Spokane winters average lows around 23F, and that cold is the single biggest driver of rodent problems here.
Reading the evidence: tracks, teeth and droppings.
The Washington Department of Fish and Wildlife gives a few details that make identification easier. Rat footprints are about half an inch long. Mouse tracks are much smaller. In Spokane winters, fresh snow along the foundation or in the garage doorway can show tracks clearly. Rats also leave bigger, rougher gnaw marks. Their incisors grow about 5 inches a year, so they chew constantly, and WDFW notes they can enlarge a quarter-inch hole to fit through. Gnawed wood, plastic or wiring with large, rough edges points to rats. Droppings help too. Mouse droppings are small and pointed. Rat droppings are larger and capsule-shaped. Deer mice are a special case. They have white bellies and two-toned tails, and they nest in garages, sheds and crawlspaces. If you are not sure whether droppings came from deer mice, clean them with the wet method anyway. Before you pick a fix, it helps to know what you have.
Dense shrubs against the house and a dripping hose bib give rodents cover and water. Trimming back and fixing drips makes the yard less inviting.Deer mice and hantavirus across Washington.
Washington sees 1 to 5 hantavirus cases a year, and about 1 in 3 people diagnosed have died. Washington reported 1 case in 2025 in provisional CDC data. Nationally, 94 percent of cases since 1993 have been west of the Mississippi. Dust from dried droppings, urine or nests gets into the air when disturbed, and breathing it in is how people get infected. Garages, sheds, crawlspaces, cabins and campers that sat closed for months are the usual places people get exposed. The CDC cleanup method lowers that risk. Ventilate for 30 minutes first. Wear gloves. Spray droppings and nests with a bleach solution of 1.5 cups per gallon of water and let it soak 5 minutes. Wipe up with paper towels and bag everything. Never sweep or vacuum. For heavy contamination, especially in enclosed spaces, hiring help with protective gear is a sensible choice. The Washington State Department of Health says infected deer mice live throughout the state, and that includes the Spokane area.
What Washington's rat rules mean for you.
Killing them is unrestricted. For a Spokane homeowner, that means you can trap rats on your own property without a permit. You do not need to call the state before setting snap traps in the garage or crawlspace. That freedom comes with responsibility. Place traps where pets and children cannot reach them, inside boxes or behind barriers if needed. If you use bait, keep it in locked, tamper-resistant stations. It also helps to know what you are catching. Deer mice are native and carry hantavirus, so treat any mouse you catch in a garage or shed with care. Wear gloves, wet the trap and mouse with bleach solution, and bag them before disposal. If a provider is involved, ask how they handle trapping, carcass removal and cleanup, especially in areas with deer mice. The Washington Department of Fish and Wildlife classifies Norway rats and roof rats as Old World rats, and it notes they are not regulated.
What a fall sealing visit should cover.
The provider should start outside. Expect a walk around the foundation looking at the sill plate, pipe and utility penetrations, dryer and bathroom vents, crawlspace vents and garage doors. WDFW notes a rat can get through a quarter-inch hole, so the provider should point out every gap that size or larger. Inside, expect a look at the garage, kitchen, under sinks, the attic and the crawlspace. The goal is to find existing activity and confirm the openings from the inside. You should leave with a written list of openings, the materials to be used, a trapping plan if rodents are already inside, and any cleanup recommendations. Ask for photos of entry points. If you had mice last winter, late August or early September is the best time to call. If you book one rodent visit a year in Spokane, make it a fall sealing visit in September or early October.
What affects the price
- The number of gaps around pipes, vents, sill plates and garage doors.
- Crawlspace access and whether vents need new screening.
- How much droppings cleanup and insulation removal is needed.
- Whether sheds, detached garages or campers are included.
- The number of follow-up trap visits.
- Timing, since sealing before the cold is usually a smaller job than trapping out an established winter nest.
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What's your biggest concern about rodents?
When to call for help
Call a professional if you hear rodents in walls or ceilings for more than a few nights, find droppings in several rooms, or see signs of rats rather than mice. Across Spokane, call early in fall if you had activity last winter, since sealing before the cold is much easier than removing rodents later. Also call before cleaning a garage, shed or crawlspace with heavy droppings, because the Washington State Department of Health says infected deer mice live throughout the state.
What you can do yourself
Many Spokane homeowners can handle a mouse or two. Snap traps baited with peanut butter, set along walls in the garage and kitchen, work well. Seal gaps under sinks and around pipes with steel wool and caulk, and replace worn garage door seals. Do this in September, before the cold arrives. A provider becomes worth it when activity keeps coming back, when you hear rodents in walls you cannot reach, or when droppings are heavy in a garage, shed or crawlspace. Finding every gap along a sill plate or crawlspace takes time and experience. Cleanup in deer mouse areas also needs care, and a provider can bring protective gear for heavy contamination.
Rodents in Spokane
Spokane is a city of about 231,000 people, founded in 1871 and known for Gonzaga, Riverfront Park and Hoopfest. Several local details matter for rodents. The warm summer continental climate brings winter lows around 23F, which drives a strong fall move indoors and keeps mice in walls and garages all winter. Summer highs near 84F and only about 17 inches of precipitation a year keep rodents outdoors in yards and gardens during the warm months. At about 1,843 feet, the city sits in eastern Washington, and the state health department says infected deer mice live statewide. Riverfront Park and other green spaces bring cover close to neighborhoods. If you rent near Gonzaga, check closets and cabinets for droppings on move-in day. With a median home value around $370,000, sealing a home before fall protects wiring, insulation and stored belongings.
Local research
Rodents in Spokane, WA: what the public record shows
Before you compare quotes, it helps to know which rodents actually live in Washington, when they are busiest around Spokane, and what the state figures look like. Everything below links to the agency or university page it came from.
Rat litter size
Old World rats are not regulated; killing is unrestricted.
WDFWRat entry hole
Footprint about 1/2 inch long; incisors grow 5 inches a year.
WDFWRodent species recorded in Washington
- House mouse (Mus musculus) — Enters at 1/4 inch; 5-10 litters per year; eats about 200 small meals a night.
- Norway rat (Rattus norvegicus) — Burrowing rat of basements, sewers and ground floors; tail shorter than head plus body.
- Roof rat (Rattus rattus) — Climber of attics and trees in warm and coastal regions; tail longer than head plus body.
- Deer mouse (Peromyscus maniculatus) — Primary U.S. hantavirus carrier; lives throughout Washington and the interior West.
When rodents are busiest around Spokane
Year-round; roof rats in Puget Sound attics.
Rules that apply in Washington
For context, nationally
- 1/4 inch (the width of a pencil) — Smallest gap a mouse can enter. CDC
- 890; 35% fatal; 94% west of the Mississippi — Hantavirus cases reported since 1993 (through 2023). CDC
Sources: Hantavirus; WDFW; CDC; Pest Notes: House Mouse; Pest Notes: Rats. Figures are quoted as the source prints them. How we check our sources
Simple ways to keep rodents away
- Seal gaps around pipes, vents and the sill plate in September.
- Replace worn garage door seals and add sweeps to exterior doors.
- Screen crawlspace and attic vents with quarter-inch hardware cloth.
- Store birdseed, grass seed and pet food in metal containers.
- Use sealed plastic bins in the garage instead of cardboard boxes.
- Move firewood away from the house and off the ground.
- Air out sheds and campers for 30 minutes before spring cleanup.
- Check for tracks in fresh snow near the foundation to spot rat activity.
Before you call, sketch where you have seen droppings or heard noise and measure any gaps you found. It makes the first visit faster and the quotes comparable.Did you know?
Rat incisors grow about 5 inches a year, which is why rats gnaw constantly.
Young rats can start breeding at just 3 to 4 months old.
About 35 percent of the 890 U.S. hantavirus cases reported from 1993 through 2023 were fatal.
Questions people ask
When do mice come inside in Spokane?
Mostly in fall, as nights cool and Spokane winter lows head toward an average of 23F. Mice and rats that spent the summer outdoors look for gaps around pipes, vents and garage doors. Sealing in September heads off a lot of winter trouble.
How common is hantavirus in Washington?
Washington sees 1 to 5 hantavirus cases a year, and about 1 in 3 people diagnosed have died, according to the state Department of Health. Infected deer mice live throughout Washington, including the Spokane area. Clean droppings with bleach solution and never sweep or vacuum.
Do I need a permit to trap rats in Washington?
No. The Washington Department of Fish and Wildlife says Old World rats, the Norway rat and roof rat, are not regulated, and killing them is unrestricted. You can trap them on your property without a permit. Use snap traps and place them away from pets and children.
How can I tell if I have rats or mice?
Size of droppings and tracks helps. WDFW says rat footprints are about half an inch long, much larger than a mouse's. Rats also gnaw larger, rougher holes. Across Spokane, fresh snow near the foundation can show tracks clearly.
How fast do rats breed?
Fast. WDFW says rats have litters of 6 to 10 young after about 3 weeks of gestation, and young can breed at 3 to 4 months. Rodents that move in during fall can grow into a much larger problem by spring.
Why do rats chew so much?
Their incisors never stop growing. WDFW notes rat incisors grow about 5 inches a year, so rats gnaw constantly to wear them down. That is why they chew through wood, plastic and wiring, and why sealing needs metal or mortar.
What is the safest way to clean a shed with mouse droppings?
Open the shed and leave for 30 minutes. Wear gloves, spray droppings and nests with a solution of 1.5 cups of bleach per gallon of water, and wait 5 minutes. Wipe up with paper towels and bag everything. Never sweep or vacuum, since that puts particles in the air.
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Sources (6)
The facts in this article come from the public sources listed above. Every home is different, so ask the company you talk to about pricing and what’s included. Published by Rodent Exterminator · Updated October 11, 2026 · How we write these guides