The short version
Rodent control in Redmond, Washington, means dealing with roof rats and Norway rats year-round, plus house mice and deer mice. Washington wildlife officials say a rat can enter through a 1/4-inch hole and chew it larger, so sealing with metal is the core of the fix. Trap what is inside, and clean droppings wet, since deer mice carry hantavirus across the state.
- Roof rats and Norway rats stay active all year in Redmond's mild, wet climate.
- A rat can squeeze through a 1/4-inch hole and gnaw it wider.
- Rat incisors grow about 5 inches a year, which is why they chew wiring.
- Washington sees 1 to 5 hantavirus cases a year; about 1 in 3 is fatal.
- Rats breed at 3 to 4 months and have litters of 6 to 10.
This is for Redmond homeowners hearing scratching in the attic, people finding droppings in garages or crawlspaces, renters in apartments and townhomes, and landlords managing several units. It is also for anyone worried about chewed wiring in a home with finished spaces, smart-home systems or expensive mechanical equipment.
What to look for
Washington wildlife officials note rats have litters of 6 to 10 young after about three weeks of gestation and can breed at 3 to 4 months, so a small problem grows fast. Rats also need very little space, entering through a 1/4-inch hole and chewing it larger. Washington's household rodents include the Norway rat, the roof rat, the house mouse and the deer mouse. Around Redmond, rats are the main concern. Roof rats are climbers that nest in attics, wall voids and dense vegetation, and the Puget Sound area is known for roof rats in attics. Norway rats burrow under decks, sheds, slabs and along foundations. House mice live in walls and cabinets. Deer mice, which carry hantavirus, live throughout the state and favor garages, sheds and outbuildings. Redmond's marine west coast climate keeps all of them active. Summers top out around 76F, winter lows average about 36F, humidity runs near 73 percent and roughly 37 inches of rain falls each year. With no deep freeze and plenty of moisture, vegetation stays thick and rodents breed year-round, with a peak in fall.
- 1Scratching or running in the attic or ceiling at night.
- 2Droppings in the attic, crawlspace or garage, larger and blunter than mouse droppings.
- 3Chewed wiring, insulation or ductwork in the attic or crawlspace.
- 4Footprints about 1/2 inch long in dust on shelves or the garage floor.
- 5Burrows under decks, sheds or along the foundation.
- 6Dark rub marks along beams, pipes or the roofline where rats squeeze through.
- 7Gnawed vent screens, soffit edges or holes in siding.
Why it’s worth acting soon
- Rats can breed at 3 to 4 months, so a small attic group can grow quickly in mild weather.
- Rat incisors grow about 5 inches a year, and constant gnawing damages wiring, ductwork and pipes.
- Deer mouse droppings in garages and sheds raise hantavirus exposure risk during cleanup.
- Urine and droppings contaminate insulation, which may need replacing.
- Entry holes get chewed wider over time, letting more rodents in.
Treatment options and typical costs
Attic and roofline exclusion
Quoted after inspection
Sealing roof vents, soffit gaps, roof junctions and points where pipes and wires enter, using hardware cloth, metal flashing and steel mesh. Rats can enter through a 1/4-inch hole and chew it larger, so soft materials fail. Ask the provider for a written list and photos of each opening sealed.
- Time
- One to three days
- Best for
- Roof rats in the attic
Crawlspace and foundation sealing
Quoted after inspection
Closing gaps around foundation vents, crawlspace access doors, utility penetrations and under decks where Norway rats burrow. In Redmond's damp soil, this can include hardware cloth below grade. Ask how the provider handles crawlspace vents and moisture.
- Time
- One to two days
- Best for
- Norway rats under the house or deck
Trapping program
Quoted after inspection
Snap traps or enclosed rat traps placed in the attic, crawlspace and garage, checked on a schedule. Traps remove rodents already inside without the risk of rats dying in walls after bait. Ask how often traps are checked and how carcasses are removed.
- Time
- Two to four weeks
- Best for
- Active rats or mice inside
Attic sanitation and insulation replacement
Quoted after inspection
Removing droppings, nests and soiled insulation, disinfecting surfaces and installing new insulation. Long-running rat activity can contaminate an attic enough to need this. Ask whether the crew wets material before removing it and what protective gear they wear.
- Time
- One to three days
- Best for
- Attics with months of rat activity
Prices are typical published ranges. Ask what’s included before you compare quotes.
Crawl spaces are where rats and mice get comfortable. Vent screens, the sill plate and any gap around pipes are worth a careful look.Roof rats in Redmond attics: a year-round tenant.
Trap rats already inside, and check sealed spots for new gnawing over the following weeks. Then seal every opening with hardware cloth, metal flashing or steel mesh. Cut limbs and tall shrubs back from the roof and siding. The fix pairs trimming with sealing. About 37 inches of rain a year and humidity near 73 percent keep trees and shrubs growing close to houses, giving rats a path to the roof. Thick vegetation helps them. Washington wildlife officials say a rat needs only a 1/4-inch hole and will chew it larger. Common entry points include soffit gaps, roof vents, the corners where two rooflines meet, gaps around plumbing vents and the spots where cable and power lines reach the house. They get in high. Once a group gets into an attic, it can stay and breed year-round. Around Redmond, where winter lows average around 36F, they never face the kind of hard freeze that slows rodents in colder places. Roof rats are climbers, and in the Puget Sound area they are known for settling into attics.
Why rats gnaw: incisors that grow 5 inches a year.
If you find gnawed wiring, call an electrician as well as a rodent provider. Hardware cloth, metal flashing, steel mesh and steel wool packed tight and sealed hold up. Foam, plastic and wood patches get chewed through. It also explains why soft sealing materials fail. Chewed wiring is a fire risk, and damaged ductwork can spread contamination through the house. Rats chew electrical wiring, low-voltage cables, HVAC ductwork, water lines and insulation. That matters in a Redmond home, where the median value is around $1,150,000 and attics and crawlspaces often hold expensive systems. So they chew on almost anything, including wood, plastic, soft metals, wiring and insulation. Without constant gnawing, their teeth would grow too long to eat. Washington wildlife officials say rat incisors grow about 5 inches a year. Rats chew because they have to. Check attics and crawlspaces at least once a year for new gnaw marks. After rodents are removed and entry points sealed, have damaged wiring repaired or replaced.
A metal vent cover with a working flap keeps mice out all winter. Plastic flaps crack in the cold and get chewed open.Deer mice and hantavirus in Washington.
The safe method is to ventilate the space for 30 minutes, put on gloves, soak droppings and nests with bleach solution at 1.5 cups per gallon of water, wait 5 minutes, then wipe up with paper towels and bag everything. When droppings and nests are swept or vacuumed, particles get into the air. The main risk is cleanup. You can recognize them by their white bellies and feet and a tail that is dark on top and pale below. Around Redmond, deer mice are more likely in garages, sheds, crawlspaces and outbuildings than in kitchens. The CDC's provisional 2025 count listed one Washington case. Deer mice live throughout Washington, and infected deer mice carry the virus that causes hantavirus pulmonary syndrome. Low case numbers are a reason for care, not panic. For heavy contamination in a crawlspace or shed, consider hiring a provider with respiratory protection.
What to ask before signing a rodent contract in Redmond.
Around Redmond, where rodents stay active year-round, thorough exclusion is the better investment. A quote that relies on bait boxes alone, without sealing, can leave rats dying in walls and keep you on a monthly bill. What happens if rats get back in? How will you handle any chewed wiring you find? What protective gear does your crew use for cleanup? Will you remove dead rodents and contaminated insulation, or is that separate? How many return visits does the price cover, and what does each extra trip cost? Do you work on the roof and in the crawlspace? Look for hardware cloth, metal flashing and steel mesh, since rats chew through soft materials. What materials will you use? Ask for photos. Questions worth asking: Which entry points did you find in the attic, roofline and crawlspace, and which are included? Compare what each provider will seal, how thoroughly they will clean up and how they will protect your home's systems. In a high-value home, the cheapest quote is rarely the best value.
Washington rules and how rats breed here.
That means a few rats in the attic in late summer can become a much larger group by winter. In Redmond's mild climate, breeding continues through much of the year, with a fall peak. Washington wildlife officials report rat litters of 6 to 10 young after about three weeks of gestation, and young rats can breed at 3 to 4 months. The reason to act quickly is the breeding pace. Deer mice, for example, are native. Native rodents are a different matter and fall under other rules, so make sure you know what you are trapping. Redmond homeowners can trap them on their own property. The state Department of Fish and Wildlife says Old World rats, which include the Norway rat and the roof rat, are not regulated, and killing them is unrestricted. Washington keeps the rules simple for invasive rats. Seal first or at the same time, trap what is inside, and keep the yard clear of food and cover. Trapping alone rarely keeps up if entry points stay open, since new rats move into the space.
What affects the price
- Roof height, pitch and the number of vents and soffit gaps to seal.
- Crawlspace access and the number of foundation vents.
- The amount of contaminated insulation in the attic or crawlspace.
- Chewed wiring or ductwork that needs repair by other trades.
- Whether both roof rats and Norway rats are present.
- The number of follow-up visits in the quote.
📊
What's your biggest concern about rodents?
When to call for help
Call a provider when you hear activity in the attic or walls, since roof rats enter high and sealing usually means roof work. Get help when you find chewed wiring, when droppings appear in the crawlspace or attic, or when trapping has not stopped activity in two weeks. In a Redmond home with expensive systems and finished spaces, early action costs less than repairs. When you call, ask what materials they use for sealing, whether they work on the roof and in the crawlspace, how many follow-up visits are included and how they handle attic cleanup.
What you can do yourself
Some rodent work is a good fit for homeowners. Trim branches and shrubs back from the roof and siding, store pet food and birdseed in metal containers, keep garbage cans closed and set a few snap traps in the garage. Seal small gaps around pipes under sinks with steel wool and caulk. Those steps help with mice and reduce pressure on the house. Where DIY gets hard is the roofline and crawlspace. Rats get in through holes as small as 1/4 inch, often at soffits, roof vents and junctions that need ladders and roof access. Crawlspaces are cramped, damp and often contaminated. Rats also avoid new traps and need careful placement. For a Redmond home, where repairs to wiring and finishes are costly, hiring out the sealing, attic trapping and cleanup often makes sense. Keep doing the yard and food-storage work yourself, since no provider can do that for you.
Rodents in Redmond
With no deep freeze and plenty of moisture, rodents stay active year-round, with a fall peak. Washington's household rodents include the Norway rat, roof rat, house mouse and deer mouse. Roof rats in Puget Sound attics are a well-known pattern. Deer mice live throughout the state and carry hantavirus, which the state health department says causes 1 to 5 cases a year, about a third of them fatal. Redmond was founded in 1912 and is now an urban city of about 77,000, known as Microsoft's home and a tech hub. With a median home value around $1,150,000, rodent damage to wiring, insulation, ductwork and finished spaces can be expensive, which makes early sealing worthwhile. The marine west coast climate brings summers near 76F, winter lows around 36F, humidity near 73 percent and about 37 inches of rain a year at an elevation of roughly 43 feet.
Local research
Rodents in Redmond, 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 Redmond, 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 Redmond
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
- Trim tree limbs and tall shrubs back from the roof and siding.
- Screen roof, soffit and foundation vents with metal mesh.
- Seal gaps around pipes and wires with steel wool and caulk or metal plates.
- Store birdseed, pet food and grass seed in metal containers.
- Keep garbage and compost in closed bins with solid bottoms.
- Clear clutter and woodpiles away from the foundation and decks.
- Check the attic and crawlspace for droppings each fall.
- Store garage and shed items in sealed plastic bins.
A good rodent quote lists the inspection, the number of trapping visits, each opening to be sealed and the material for it, and any cleanup.Did you know?
A rat footprint is only about 1/2 inch long, small enough to miss unless you check dusty surfaces.
Rat pregnancies last only about three weeks, according to Washington wildlife officials.
Washington was one of eight western states with a hantavirus case in the CDC's provisional 2025 count.
Questions people ask
Do roof rats live in Redmond attics?
Around Redmond, mild winters around 36F let them stay active year-round. Listen for scratching at night, check the attic for droppings and look for gnawed vents and soffit edges. Yes. Roof rats are one of Washington's household rodents, and the Puget Sound area is known for roof rats in attics.
Is hantavirus a risk in Washington?
Infected deer mice live throughout the state. Around Redmond, the risk comes from cleaning garages, sheds and crawlspaces with deer mouse droppings, so clean wet and never sweep. It is rare but serious. The Washington State Department of Health reports 1 to 5 cases a year, and about 1 in 3 people diagnosed have died.
How small a hole can a rat get through?
Foam and plastic do not hold. Check soffits, roof vents, foundation vents and pipe entries. About 1/4 inch, according to Washington wildlife officials, and rats chew small holes larger. That is why sealing has to use metal materials like hardware cloth, flashing and steel mesh.
Why do rats chew wires?
Wiring, ductwork and pipes are common targets. In a Redmond home with expensive electrical systems, that gnawing can mean costly repairs and fire risk. Their front teeth never stop growing. Washington wildlife officials say rat incisors grow about 5 inches a year, so rats gnaw constantly to wear them down.
How fast do rats breed?
In a mild climate like Redmond's, breeding continues through much of the year. Acting when you first hear scratching saves a lot of work. Quickly. Washington wildlife officials report litters of 6 to 10 young after about three weeks of gestation, and young rats can breed at 3 to 4 months.
Can I kill rats on my own property in Washington?
You can trap them on your property. Keep traps away from children and pets, and use enclosed traps where needed. Native rodents fall under different rules. Yes. Washington wildlife officials say Old World rats, which include Norway rats and roof rats, are not regulated, and killing them is unrestricted.
Are rodents worse in fall in Redmond?
Redmond's winter lows average about 36F, so rodents never face a hard freeze, but cooler, wetter weather still pushes them toward attics and crawlspaces. Sealing in late summer and checking the attic in fall catches problems early. Activity runs all year, with a peak in fall.
Nearby cities
Related guides
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